Research ArticleThe Rainfall Intensity Effects on 1ndash13 GHz UWB-Based 5GSystem for Outdoor Applications

Joko Suryana

School of Electrical Engineering and Informatics Institut Teknologi Bandung Bandung Indonesia

Correspondence should be addressed to Joko Suryana jokosuryanasteiitbacid

Received 6 March 2017 Revised 29 May 2017 Accepted 1 August 2017 Published 20 September 2017

Academic Editor Ernestina Cianca

Copyright copy 2017 Joko SuryanaThis is an open access article distributed under the Creative Commons Attribution License whichpermits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This paper reports a research contribution on tropical outdoor channel characterization in 1ndash13GHz band for 5G systems This1ndash13GHz ultra-wideband (UWB) channel characterization is formulated with rain intensity as the most important variable from20mmh to 200mmh Tropical rain will cause pulse broadening and distorts the transmitted symbols so the probability of symbolerrors will increase In this research the bit error rate (BER) performance evaluation is done using both matched filtering orcorrelator-based receivers At no rain conditions BER 10minus6 will be attained at signal to noise ratio (SNR) 5 dB but at rainfallintensity 200mmh the BER will fall to 10minus2 for matched filter and 5 times 10minus2 for correlator-based receivers For improving the BERperformance an adaptive nonlinear phase equalizer is proposed which adopts multiple allpass biquad infinite impulse response(IIR) filters combined with low-order finite impulse response (FIR) filter to mitigate the nonlinearity phase and differentialattenuation of magnitude responses due to antenna and tropical outdoor UWB channel effects Our simulation results show thatthe proposed equalizer has worked successfully with BER 10minus6 on the rain rate that is exceeded for 001 of the time (119877001) rainintensity or 9999 availability In addition at rainfall rate 120mmh the proposed nonlinear phase equalizer can give 9 dB signalimprovement

1 Introduction

Like other mobile communication systems the applicationsof UWB-based 5Gmobile systems at a specific environmentrequires thorough knowledge of the propagation charac-teristics in that environment Until now study of UWBpropagation for 5G applications at outdoor environment isstill limited Many researchers are doing research on outdoorUWB channel characterizations at multipath effects and itspath loss only [1ndash4] In addition there is a lack of adequateresearch [3 5ndash7] on the effects of atmospheric layers at1ndash13GHz especially in the tropical areasTherefore the studyof tropical outdoor UWB channel characterization is veryrelevant to do for preparing UWB-based 5G applications inthe near future

The 1ndash13GHz band itself is comprised of two 5G candi-date spectrum category 1ndash6GHz as ldquobelow 6GHz spectrumrdquoand 6ndash13 as ldquoabove 6GHz spectrumrdquo As 5G systems developover time the 1ndash6GHz mobile spectrum bands will bevaluable to allow the smooth migration from 4G LTE usage

to 5G while 6ndash13GHz spectrum band is attractive in whichthe existing technology and architecture might be adaptedto work in this range which is closest to existing cellularfrequencies Therefore this 1ndash13GHz spectrum band is ofspecific interest as it might be able to employ existing cellulartechnologies with little additional development requiredMoreover the 1ndash13GHz spectrum band is also covering the31ndash106GHz UWB channel which has been adopted forUWB outdoor communication applications at tropical areas

Unfortunately the influence of the tropical outdoor chan-nel on the UWB-based 5G communication system perfor-mance has not quantitatively assessed in a comprehensivemanner yet In this case the impulse response of end-to-endtropical outdoor channel will distort the pulse sent by UWBsystems Therefore it is necessary to formulate the distortioneffects of UWB signals by the atmosphere of tropical areas interms of BER performance of UWB receiver systems

To maintain the BER performance of UWB systems fromoutdoor channel distortions and the effects of UWB antennaimperfections a mitigation technique is required to track

HindawiWireless Communications and Mobile ComputingVolume 2017 Article ID 6495145 13 pageshttpsdoiorg10115520176495145

2 Wireless Communications and Mobile Computing

HＮＩＮ()

GtGr

VＣＨ() VＩＯＮ()

Figure 1 Tropical outdoor UWB channel model

the tropical outdoor channel adaptively Therefore there ishigh demand to develop an adaptive equalization algorithmfor compensating the pulse distortion as a result of thephase response nonlinearity as well as the lack uniformity ofmagnitude response

The purposes of this research are (1) performing thecharacterization of tropical outdoor channel 1ndash13GHz fre-quency band with a numerical simulation of UWB signaltransmitting through the layer of atmosphere with a varietyof rain (the results of numerical simulations are validatedwith field measurements at the ITB campus environment)(2) calculating the quantification of pulse distortion byatmospheric layer propagation in the tropical areas for theformulation of UWB-based 5G communication systems interms of BER (the BER performance is formulated withrainfall intensity as the most important parameter on twotypes of UWB receivers that is matched filter-based and thecorrelator-based receivers) and (3) developing an adaptivenonlinear phase equalization algorithm with low complexitybut effectively to overcome the pulse distortion Accordingto usual performance requirements of 5G systems we fixed atarget BER equal to 10minus6 and 9999 reliability for 500MBpsUWB-based 5G at tropical outdoor applications

2 Basic Theory

21 Tropical Outdoor UWB Channel Tropical outdoor UWBchannel is defined as a transmission channel for outdoorUWB applications where between transmitter (TX) andreceiver (RX) there is an atmospheric medium This atmo-sphere medium contains the O2 H2O CO2 and other gasesas well as hydrometeors such as rain clouds and fog Figure 1illustrates the UWB communication system in a tropicaloutdoorUWB channel TX transmits anUWB signal towardsthe RX through atmospheric layer in line of sight manner

An UWB signal transmission in a tropical atmospherelayerwill experience attenuation phase shift and the additionof delay time Transfer function of tropical outdoor UWBchannel as Figure 1 can bemodeled by the equation frequencyregion as follows

119867tot (120596) = 119881out (120596)119881in (120596) = 119866119905 (120596) 119866119891 (120596) 119866119886 (120596) 119866119903 (120596) (1)

with

(i) 119866119905 119866119903 are transfer function of Tx or Rx antennas withspecific return loss 11987821(120596) and for identical antennas119866119905 or 119866119903 is formulated [8]

119866119905 (120596) = 119866119903 (120596) = radic 2120587119903119888119895120596 11987821 (120596) 1198901198951205961199031015840119888 (1a)(ii) 119866119891 is transfer function of free space propagation as

Friis formula in frequency domain [9]

119866119891 (120596 119889) = 1198882120596119889119890minus119895120596119889119888 (1b)(iii) 119866119886 is transfer function of atmospheric layer

119866119886 (120596) = 119864 (119889)119864119900 = exp [minus 120572 (120596) + 119895120573 (120596) 119889] (1c)with 120572 and 120573 defined as [10]

120572 (120596) + 119895120573 (120596) = 12058222120587 intinfin0

1198780 [119899119888 119886120582] sdot 119873 (119886) sdot 119889119886 (1d)The atmosphere medium consists of gases such as O2

H2O CO2 and other gases as well as hydrometeors such asrain clouds and fog In this study the rain-filled medium ismodeled by raindrops Mie scattering which are statisticallydistributed in size as Marshall Palmer distribution [11] withcomplex permittivity based on Liebe and Hufford measure-ments [12] After the impulse response of atmospheric layeris numerically obtained the next step is to calculate a pulseshape distortion in terms of amplitude pulse width anddelay time as a function of rainfall intensity 0 20 50 100150 and 200mmh Numerical simulation results are thenvalidated by field measurements using a rain simulator andvector network analyzer 0ndash135 GHz at campus environment

22 Quantification of the Tropical Atmosphere Effect on UWBPerformance UWB system BER formulation is limited toUWB system with antipodal modulation and using matchedfilter and correlator-based receivers as [13] There are twoscenarios formulated BER performance (1) assuming theantenna system is ideal and (2) assuming the antenna systemis realistic

221 Performance of Matched Filter-Based Receiver with IdealUWB Antenna The energy alteration per bit due to pulsedistortions is to be accommodated in the BER equationas well as the effect of the gainloss due to the use of thematched filter receiver Pulse distortion impacts on reducingthe energy per bit of signal Figure 2 illustrates the model ofmatched filter-based UWB receiver

119867119898 (120596) = radic2BW(12120587) intinfin

minusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596 sdot 119881lowastout (120596) (2)

119881119898 (120596) = 119867119898 (120596) sdot 119881out (120596) (3)

BER119898 = 119876 [radic 2 sdot 119862119898 sdot 119866119898BW sdot 119878119861119903119873 ] (4)

Wireless Communications and Mobile Computing 3

Tx antenna Rx antenna

VＣＨ(t)

VＩＯＮ (t) + n(t)

Ha(f) Matchedlter

Vm(t)

VＩＯＮ(t)

Atmosphericchannel

Figure 2 Model of matched filter-based UWB receiver

VＣＨ(t)

VＣＨ(t)

VＩＯＮ (t) + n(t)Ha(f)

Atmosphericchannel

Correlator Vc(t)

Tx antenna Rx antenna

Figure 3 Model of correlator-based UWB receiver

For antipodal modulation the BER performance ofmatched filter-based UWB receiver is as (4) In this case119861119903 is the data rate BW is the bandwidth and 119862119898 and 119866119898respectively are the correlation coefficients and the gain ofmatched filter

119862119898 = max 10038161003816100381610038161003816intinfinminusinfin 119881119898 (120596) 11989011989512059611990511988912059610038161003816100381610038161003816radicintinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596 sdot intinfinminusinfin

1003816100381610038161003816119867119898 (120596)10038161003816100381610038162 119889120596119866119898 = intinfin

minusinfin

1003816100381610038161003816119881119898 (120596)10038161003816100381610038162 119889120596intinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596(5)

222 Performance of Correlator-Based Receiver with IdealUWB Antenna As the matched filter-based receiver thechange of energy per bit due to pulse shape distortion alsooccurs in correlator-based receiver Figure 3 illustrates themodel of correlator-based UWB receiver

119867119888 (120596) = radic2BWintinfinminusinfin

1003816100381610038161003816119881in (120596)10038161003816100381610038162 119889120596 sdot 119881lowastin (120596) (6)

119881119888 (120596) = 119867119888 (120596) sdot 119881out (120596) (7)

BER119888 = 119876 [radic 2 sdot 119862119888 sdot 119866119888 sdot BW sdot 119878119861119903119873 ] (8)

For antipodal modulation the BER performance ofcorrelator-based UWB receiver is as (8) with 119861119903 being thedata rate BW the bandwidth and 119862119888 and 119866119888 respectively

the correlation coefficients and the gain of correlator-basedreceiver

119862119888 = max 10038161003816100381610038161003816intinfinminusinfin 119881119888 (120596) 11989011989512059611990511988912059610038161003816100381610038161003816radicintinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596 sdot intinfinminusinfin

1003816100381610038161003816119867119888 (120596)10038161003816100381610038162 119889120596119866119888 = intinfin

minusinfin

1003816100381610038161003816119881119888 (120596)10038161003816100381610038162 119889120596intinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596(9)

223 Performance of UWB Receivers with Realistic UWBAntenna In the previous sections we have discussed theperformance evaluation of UWB communications systemsin dispersive outdoor tropical UWB channels with idealantenna This section presents a derivation of BER equationfor tropical outdoor channel with realistic antennas Theinfluence of distortion by the antenna system is very depen-dent on the parameters 11987811 and 11987821 and the gain of the antennasystemThe effects of 11987811 and 11987821 parameters and antenna gaincan be represented by a fidelity value which is defined in [14]

119865 (119903 (119905) 119901 (119905))= max120591

1003816100381610038161003816100381610038161003816100381610038161003816100381610038161003816intinfinminusinfin

119903 (119905) sdot 119901 (119905 minus 120591)radicintinfinminusinfin

|119903 (119905)|2 119889119905 intinfinminusinfin

1003816100381610038161003816119901 (119905)10038161003816100381610038162 1198891199051198891199051003816100381610038161003816100381610038161003816100381610038161003816100381610038161003816 (10)

where fidelity profile 119865(119903(119905) 119901(119905)) is a measure of similaritybetween 119903(119905) and 119901(119905) In this case 119903(119905) is a received signalafter passing through the antennas (both transmit and receivesides) and 119901(119905) is a template signal at receiverWhen anUWBsystem uses realistic antenna with specific return loss 11987811 thegain the transfer function 11987821 and the BER equation for bothreceiving systems become

BER119898 = 119876 (radic 2119865119862119898119866119898BW sdot 119878119861119903 sdot 119873 )

BER119888 = 119876 (radic 2119865119862119888119866119888BW sdot 119878119861119903 sdot 119873 ) (11)

It is assumed that we use same tropical outdoor channelmodel as in previous section but in this case we used TX andRX realistic antennas with specific fidelity profile 11986523 Adaptive Nonlinear Phase Equalizer In this study it isproposed an adaptive nonlinear phase equalizer for compen-sating the pulse distortion by combining allpass biquad IIR[15] and FIR filters with a channel estimator block as Figure 4

Allpass biquad IIR filter is used to compensate nonlinearphase response that comes from the tropical outdoor channeland the antenna Meanwhile to compensate the magnituderesponse we use low-order FIR filter cascaded with theallpass biquad IIR filter For measuring the instantaneouschannel condition channel estimatorwith its training patternsignal is used to calculate the channel transfer functionperiodically

In this case the end-to-end transmission channel isrepresented by convolving the tropical outdoorUWBchannel

4 Wireless Communications and Mobile Computing

Pulse in

Pulse out

Allpass IIR FIR

Channel estimator

Outdoor tropical

angHH

(H)＝ＢＨＨＦ + ＨＮＨＨ

Figure 4 Block diagram of proposed adaptive nonlinear phaseequalizer

0mmh120 mmh

200 400 600 800 1000 1200 1400 1600 1800 20000

minus1

minus05

0

05

1

Am

plitu

de (V

olt)

UWB pulse waveforms at outdoor tropical channel

Nth sample

Figure 5 Pulse shapes in a tropical outdoor UWB channel

with a dispersive UWB antenna system The rainfall rateused in this simulation is 119877001 of Bandung [16] the antennaselected is Log Periodic antenna which has bandwidth at2ndash8GHz [17] It is assumed that the distance between TXand RX is 10-meter long A Gaussian 01333 ns pulse shapesafter passing through the tropical outdoor UWB channel at0mmh and 120mmh and can be seen in Figure 5

Antenna used in this simulation is a Log Periodic antennawith wide bandwidth but has a dispersive impulse responseAs in [17] Log Periodic is one of antenna classes which havewide bandwidth and dispersive impulse response Frequencyand time domain characteristics of the 2ndash8GHz Log Periodicantenna can be seen in Figure 6

3 Results and Discussion

31 Characterization of Tropical Outdoor UWB Channel Thenumerical simulation results of the attenuation coefficient perkm and phase coefficient per km [18] can be seen in Figure 7When the distance between TX and RX is known then by

using the curve in Figure 7 we can obtain the magnituderesponse and the phase response of the tropical outdoorUWB channel

A transfer function of a tropical outdoor UWB channelcan then be calculated by combining the magnitude andphase responses as a function of frequency and rainfallintensity at 0 20 50 100 150 and 200mmh And by usingthe inverse Fourier transform we can determine the channelimpulse response

In this research author used short range of tropicaloutdoor communication model for both 4-meter and 10-meter distanceThe reason behind choosing these short rangecomes from the fact that our rain simulator facility asdescribed on Section 32 has maximum length of about 10meter Due to its rain attenuation proportionality propertiesto range our short range simulation andmeasurement resultswill lead us to estimate the rain effects for longer range as 5Grealistic applications

311 Numerical Simulation Results of Impulse Response ofTropical Outdoor UWB Channel at 119889 = 4 Meter Figure 8 isnumerical simulation results of the channel impulse responseof tropical outdoor at 1ndash13GHz band as a function of onfrequency on a variety of rainfall intensity for TX and RXdistance 119889 = 4 meters

From Figure 8 it can be seen that as the rainfall intensitybecomes greater then the impulse response will be morebroadened and delayed and its amplitude will be reducedHowever at distance between TX and RX antenna 119889 = 4meters the influence of rainfall intensity is small enough

312 Numerical Simulation Results of Impulse Response ofTropical Outdoor UWB Channel at 119889 = 10 Meters In oursecond calculation of impulse response of tropical outdoorUWB channel we assumed that the distance between theTX and RX antenna is 10 meters By comparing the resultsof calculations on two different distances d it is expected tosee the effect of distance on the impulse response profilesFigure 9 shows that at distance 119889 = 10 meters the pulsedistortion is higher than at 119889 = 4 meters

At very high rainfall intensity (200mmh) the impulseresponse has amplitude shrinking more broadening anddelay

From the numerical results at a distance of 119889 = 4m and119889 = 10m as shown in Figures 8 and 9 we may conclude thatthe intensity of tropical rainfall affects the changing shapeof the channel impulse response distortion which occurredwith an increasing delay amplitude reduction and pulseduration broadening In this case the distance also giveseffect proportional to the pulse distortion

32 Tropical Outdoor UWB Channel Measurements Fig-ure 10 shows the configuration of UWB pulse propagationmeasurements in an outdoor environment

This measurement setup consists of an array of watersprayers vector network analyzer rain gauge and TX and RXantennas The maximum range of our outdoor measurementwhich can be achieved is 10 meters with a variation of rainfall

Wireless Communications and Mobile Computing 5

times109

s21Frequency response s21Impulse response

2 4 6 80 141210

Frequency (Hz)

minus90

minus80

minus70

minus60

minus50

minus40

minus30

minus20

Am

plitu

de (d

B)

minus6

minus4

minus2

0

2

4

6

Am

plitu

de (s

minus1)

50 15 20 2510 30

Time (ns)

times10minus3

Figure 6 Log periodic antenna characteristics

intensity from 0 to 200mmh The device used in outdoorUWB channel measurement consists of the following

(1) Vector Network Analyzer (VNA) 0ndash13GHz(2) Array of water sprayers as a tropical rain simulator

that has intensity control to simulate different rainfallintensities 0 20 50 100 150 and 200mmh

(3) Rain gauge a device for measuring rainfall intensity(4) A pair of 1ndash13GHz UWB antennas as the photograph

in Figure 11 and their frequency and time domaincharacteristics as in Figure 12

321 Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 4 Meters Tropical outdoor channel measurementswere performed using the frequency domain approach as 11987821parameter To display the tropical outdoor channel impulseresponse in time domain the measured 11987821 parameter isthen processed by inverse Fourier transform using MATLABsoftware Figure 13 is the result of the channel impulseresponsemeasurements of tropical outdoor band 1ndash13GHz atdifferent rainfall intensity for TX and RX distances at 119889 = 4meters before and after deconvolution and noise filtering

Deconvolution process conducted on raw impulse re-sponse data is intended to eliminate the distortion effectsof TX and RX antennas To eliminate the noise from theraw data we used simple filtering with a moving averagefilter From Figure 13 we can see that as the rainfall intensitybecomes greater then the impulse responsewill be broadenedand more delayed and its amplitude will reduce In this caseat 119889 = 4 meters the influence of rainfall intensity is not toolarge so the impulse response of the tropical outdoor channelalmost coincides

322Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 10 Meters In our second measurement of tropical

outdoor UWB channel we set the distance between theantenna TX and RX antenna at 10 meters By comparingthe measurement results of two different distances 119889 it isexpected to see the effect of distance to the channel impulseresponse

Figure 14 shows that influence of rain intensity on thedistance 119889 = 10 meters is higher than the measurementresult at 119889 = 4 meters The impulse response of tropicaloutdoor UWB channel at very high rainfall (200mmh) hasamplitude shrinking so the impulse response width and ashift towards the main axis become larger than when thereis no rain (0mmh)

When we compare the results of numerical simulationand measurement results of the channel impulse responsesas Figures 8 9 13 and 14 we see that there is a strong corre-spondence between themeasurement results with simulationresults both for the pulse broadening the time shifted andthe amplitude reduction of impulse responses

The curves in Figures 15 16 and 17 consecutively quanti-tatively showed us pulse broadening the time shifted and theamplitude reduction of impulse responses at distance 119889 = 4and 119889 = 10 meters as a function of rainfall intensity

The three curves confirmed that the range and variationof rainfall intensity impact on pulse broadening the timeshifted and the amplitude reduction of impulse respons-es

33 Quantification of the Tropical Atmosphere Effect on UWB-Based 5G Performance In this scenario UWB-based 5Gsystems is assumed to have 500MBps with antipodal modu-lation for outdoor applications at tropical areas The UWB-based 5G system operates at 31ndash106GHz for achieving75 GHz with very low output power density

331 BER Performance of Matched Filter-Based Receiver withIdeal Antenna Figure 18 presents the BER performance of

6 Wireless Communications and Mobile Computing

minus50

minus40

minus30

minus20

minus10

0

(Deg

ree

km)

0 4 6 82 12 14 16 18 2010

Frequency (GHz)

4 6 82 12 14 16 18 2010

Frequency (GHz)

0mmh20mmh50mmh

0mmh20mmh50mmh

100mmh150mmh200 mmh

100mmh150mmh200 mmh

0

2

4

(dB

km)

6

8

10

12

14

outdoor UWB channelPhase shiedkm of 1ndash13 GHz tropical

Attenuationkm of 1ndash13 GHz tropical outdoor UWB channel

Figure 7 Magnitude and phase response of tropical outdoor UWBchannel at 1ndash13GHz band

UWB-based 5G system using matched filter-based receiverwith ideal antenna at 10 meter distance and bitrate 500Mbpsfor several of rainfall intensities From this figure we can seethat the BER performance curve decreases with increasingrainfall intensity which occurs along the path between the TXand RX

At 10minus6 BER performance the SNR requirements mustbe worth 5 8 12 16 175 and 18 dB for rainfall intensityconditions respectively 0 20 50 100 150 and 200mmh Inother words for keeping 10minus6 BER performance continuously

4

3

2

1

0

minus1

minus23 302 304 306 308 31

times10minus4

times10minus9

Volta

ge (v

olt)

Time (seconds)

Simulated impulse response of outdoord = 4 mtropical UWB channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

Figure 8 Simulated impulse response of tropical outdoor UWBchannel on 119889 = 4m

4

3

2

1

0

minus1

minus23

times10minus4

Volta

ge (v

olt)

302 304 306 308 31

times10minus9Time (seconds)

Simulated impulse response of outdoor

0mmh20mmh50mmh

100mmh150mmh200 mmh

d = 10 mtropical UWB channel

Figure 9 Channel impulse response of tropical outdoor UWB on119889 = 10m

in various conditions of rain the required fading margin isminimum 13 dB

Meanwhile if the benchmark performance using 119877001rainfall intensity is 120mmh for Bandung the requiredfading margin is 11 dB The BER curves in Figure 18 alsoshow that at fixed SNR conditions such as 5 dB then theBER performances are respectively 10minus6 10minus4 10minus3 and

Wireless Communications and Mobile Computing 7

Water

Antenna 1

Antenna 2

Rain intensitycontrollerVNA 0ndash13 GHz

sprayer

Rain gauge

Figure 10 Tropical outdoor channel measurement setup

Figure 11 Photograph of antenna used for UWB channel measure-ments

10minus2 for rainfall intensity at 0mmh 20mmh 50mmh and100mmh

332 BER Performance of Correlator-Based Receiver withIdeal Antenna Here as in Figure 19 the BER performanceof UWB system is using correlator-based receiver with idealantenna at 10meters distance and bitrate 500Mbps for severalof rainfall intensities From this figure we see that BER curvesdecrease with increasing rainfall intensity which occurs alongthe path between the TX and RX At 10minus6 BER performanceSNR requirements should be worth 7 10 14 18 20 and22 dB for rainfall intensity conditions respectively 0 2050 100 150 and 200mmh In other words to obtain theBERperformance 10minus6 continuously the necessary due fadingmargin is minimum 15 dB

BER curves at Figure 19 also show that at fixed SNR con-ditions such as 7 dB the BER then respectively is 10minus6 10minus510minus3 and 5times10minus1 for rainfall 0mmh 20mmh 50mmh and100mmh Comparing the BER performance curve betweenmatched filter and correlator-based receiver we can be seethat matched filter is 3ndash5 dB better than correlator-basedreceiver

333 BER Performance by Tropical Outdoor Channel andRealistic UWB Antenna The simulation results of BER per-formance evaluation of tropical outdoor channel with realis-tic antenna can be seen in Figures 20 and 21 with matchedfilter and correlator-based receiver respectively From thecurves in Figure 20 we can see that the UWB systemperformance is strongly influenced by the transient responsesof antenna and tropical outdoor channel In the matchedfilter-based receiver the use of realistic UWB antenna causesa decrease of 8-9 dB SNR while the correlator-based receiverdecreases SNR falls by 9-10 dB

34 UWB-Based 5G Bit Rate Reduction due to Tropical Out-door UWB Channel and Dispersive Antenna The effects ofrainfall intensity and the dispersive antenna to a reduction inbitrate of UWB communication system is summarized as inFigure 22 The specifications of UWB system are BER at 10minus6maintained bandwidth of 75 GHz and bitrate in additivewhite Gaussian noise (AWGN) condition at 500Mbps and 10meters distance

From Figure 22 we also can see that the intensity ofrainfall has a direct impact on the reduction in bitrate ofUWBcommunication systems The higher the rainfall the greaterthe reduction in data rate for all scenarios In an ideal scenariowith ideal antenna at rainfall intensity 200mmh the bitratewent down from 500Mbps (without rain) to 25Mbps for thematched filter and 15Mbps for the correlator-based receiverMeanwhile in realistic antenna scenarios at rainfall intensity200mmh the bitrate declined from 50Mbps (without rain)to 2Mbps for matched filter and 1Mbps for the correlator-based receiver

35 Adaptive Nonlinear Phase Equalizer Theproposed adap-tive nonlinear phase equalizer is used for mitigating thedistortions due to tropical outdoor channel and comes fromdispersive antennaThe target performance criteria of UWB-based 5G system for outdoor applications are using antipo-dal modulation operating frequency from 31 to 106GHzrequired SNR set to 10 dB for 119877 = 500Mbps power marginprovided as 5 dBminimumBER 10minus6 with availability 9999

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

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Active and Passive Electronic Components

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RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

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Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

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Navigation and Observation

International Journal of

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DistributedSensor Networks

International Journal of

Wireless Communications and Mobile Computing 3

Tx antenna Rx antenna

VＣＨ(t)

VＩＯＮ (t) + n(t)

Ha(f) Matchedlter

Vm(t)

VＩＯＮ(t)

Atmosphericchannel

Figure 2 Model of matched filter-based UWB receiver

VＣＨ(t)

VＣＨ(t)

VＩＯＮ (t) + n(t)Ha(f)

Atmosphericchannel

Correlator Vc(t)

Tx antenna Rx antenna

Figure 3 Model of correlator-based UWB receiver

For antipodal modulation the BER performance ofmatched filter-based UWB receiver is as (4) In this case119861119903 is the data rate BW is the bandwidth and 119862119898 and 119866119898respectively are the correlation coefficients and the gain ofmatched filter

119862119898 = max 10038161003816100381610038161003816intinfinminusinfin 119881119898 (120596) 11989011989512059611990511988912059610038161003816100381610038161003816radicintinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596 sdot intinfinminusinfin

1003816100381610038161003816119867119898 (120596)10038161003816100381610038162 119889120596119866119898 = intinfin

minusinfin

1003816100381610038161003816119881119898 (120596)10038161003816100381610038162 119889120596intinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596(5)

222 Performance of Correlator-Based Receiver with IdealUWB Antenna As the matched filter-based receiver thechange of energy per bit due to pulse shape distortion alsooccurs in correlator-based receiver Figure 3 illustrates themodel of correlator-based UWB receiver

119867119888 (120596) = radic2BWintinfinminusinfin

1003816100381610038161003816119881in (120596)10038161003816100381610038162 119889120596 sdot 119881lowastin (120596) (6)

119881119888 (120596) = 119867119888 (120596) sdot 119881out (120596) (7)

BER119888 = 119876 [radic 2 sdot 119862119888 sdot 119866119888 sdot BW sdot 119878119861119903119873 ] (8)

For antipodal modulation the BER performance ofcorrelator-based UWB receiver is as (8) with 119861119903 being thedata rate BW the bandwidth and 119862119888 and 119866119888 respectively

the correlation coefficients and the gain of correlator-basedreceiver

119862119888 = max 10038161003816100381610038161003816intinfinminusinfin 119881119888 (120596) 11989011989512059611990511988912059610038161003816100381610038161003816radicintinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596 sdot intinfinminusinfin

1003816100381610038161003816119867119888 (120596)10038161003816100381610038162 119889120596119866119888 = intinfin

minusinfin

1003816100381610038161003816119881119888 (120596)10038161003816100381610038162 119889120596intinfinminusinfin

1003816100381610038161003816119881out (120596)10038161003816100381610038162 119889120596(9)

223 Performance of UWB Receivers with Realistic UWBAntenna In the previous sections we have discussed theperformance evaluation of UWB communications systemsin dispersive outdoor tropical UWB channels with idealantenna This section presents a derivation of BER equationfor tropical outdoor channel with realistic antennas Theinfluence of distortion by the antenna system is very depen-dent on the parameters 11987811 and 11987821 and the gain of the antennasystemThe effects of 11987811 and 11987821 parameters and antenna gaincan be represented by a fidelity value which is defined in [14]

119865 (119903 (119905) 119901 (119905))= max120591

1003816100381610038161003816100381610038161003816100381610038161003816100381610038161003816intinfinminusinfin

119903 (119905) sdot 119901 (119905 minus 120591)radicintinfinminusinfin

|119903 (119905)|2 119889119905 intinfinminusinfin

1003816100381610038161003816119901 (119905)10038161003816100381610038162 1198891199051198891199051003816100381610038161003816100381610038161003816100381610038161003816100381610038161003816 (10)

where fidelity profile 119865(119903(119905) 119901(119905)) is a measure of similaritybetween 119903(119905) and 119901(119905) In this case 119903(119905) is a received signalafter passing through the antennas (both transmit and receivesides) and 119901(119905) is a template signal at receiverWhen anUWBsystem uses realistic antenna with specific return loss 11987811 thegain the transfer function 11987821 and the BER equation for bothreceiving systems become

BER119898 = 119876 (radic 2119865119862119898119866119898BW sdot 119878119861119903 sdot 119873 )

BER119888 = 119876 (radic 2119865119862119888119866119888BW sdot 119878119861119903 sdot 119873 ) (11)

It is assumed that we use same tropical outdoor channelmodel as in previous section but in this case we used TX andRX realistic antennas with specific fidelity profile 11986523 Adaptive Nonlinear Phase Equalizer In this study it isproposed an adaptive nonlinear phase equalizer for compen-sating the pulse distortion by combining allpass biquad IIR[15] and FIR filters with a channel estimator block as Figure 4

Allpass biquad IIR filter is used to compensate nonlinearphase response that comes from the tropical outdoor channeland the antenna Meanwhile to compensate the magnituderesponse we use low-order FIR filter cascaded with theallpass biquad IIR filter For measuring the instantaneouschannel condition channel estimatorwith its training patternsignal is used to calculate the channel transfer functionperiodically

In this case the end-to-end transmission channel isrepresented by convolving the tropical outdoorUWBchannel

4 Wireless Communications and Mobile Computing

Pulse in

Pulse out

Allpass IIR FIR

Channel estimator

Outdoor tropical

angHH

(H)＝ＢＨＨＦ + ＨＮＨＨ

Figure 4 Block diagram of proposed adaptive nonlinear phaseequalizer

0mmh120 mmh

200 400 600 800 1000 1200 1400 1600 1800 20000

minus1

minus05

0

05

1

Am

plitu

de (V

olt)

UWB pulse waveforms at outdoor tropical channel

Nth sample

Figure 5 Pulse shapes in a tropical outdoor UWB channel

with a dispersive UWB antenna system The rainfall rateused in this simulation is 119877001 of Bandung [16] the antennaselected is Log Periodic antenna which has bandwidth at2ndash8GHz [17] It is assumed that the distance between TXand RX is 10-meter long A Gaussian 01333 ns pulse shapesafter passing through the tropical outdoor UWB channel at0mmh and 120mmh and can be seen in Figure 5

Antenna used in this simulation is a Log Periodic antennawith wide bandwidth but has a dispersive impulse responseAs in [17] Log Periodic is one of antenna classes which havewide bandwidth and dispersive impulse response Frequencyand time domain characteristics of the 2ndash8GHz Log Periodicantenna can be seen in Figure 6

3 Results and Discussion

31 Characterization of Tropical Outdoor UWB Channel Thenumerical simulation results of the attenuation coefficient perkm and phase coefficient per km [18] can be seen in Figure 7When the distance between TX and RX is known then by

using the curve in Figure 7 we can obtain the magnituderesponse and the phase response of the tropical outdoorUWB channel

A transfer function of a tropical outdoor UWB channelcan then be calculated by combining the magnitude andphase responses as a function of frequency and rainfallintensity at 0 20 50 100 150 and 200mmh And by usingthe inverse Fourier transform we can determine the channelimpulse response

In this research author used short range of tropicaloutdoor communication model for both 4-meter and 10-meter distanceThe reason behind choosing these short rangecomes from the fact that our rain simulator facility asdescribed on Section 32 has maximum length of about 10meter Due to its rain attenuation proportionality propertiesto range our short range simulation andmeasurement resultswill lead us to estimate the rain effects for longer range as 5Grealistic applications

311 Numerical Simulation Results of Impulse Response ofTropical Outdoor UWB Channel at 119889 = 4 Meter Figure 8 isnumerical simulation results of the channel impulse responseof tropical outdoor at 1ndash13GHz band as a function of onfrequency on a variety of rainfall intensity for TX and RXdistance 119889 = 4 meters

From Figure 8 it can be seen that as the rainfall intensitybecomes greater then the impulse response will be morebroadened and delayed and its amplitude will be reducedHowever at distance between TX and RX antenna 119889 = 4meters the influence of rainfall intensity is small enough

312 Numerical Simulation Results of Impulse Response ofTropical Outdoor UWB Channel at 119889 = 10 Meters In oursecond calculation of impulse response of tropical outdoorUWB channel we assumed that the distance between theTX and RX antenna is 10 meters By comparing the resultsof calculations on two different distances d it is expected tosee the effect of distance on the impulse response profilesFigure 9 shows that at distance 119889 = 10 meters the pulsedistortion is higher than at 119889 = 4 meters

At very high rainfall intensity (200mmh) the impulseresponse has amplitude shrinking more broadening anddelay

From the numerical results at a distance of 119889 = 4m and119889 = 10m as shown in Figures 8 and 9 we may conclude thatthe intensity of tropical rainfall affects the changing shapeof the channel impulse response distortion which occurredwith an increasing delay amplitude reduction and pulseduration broadening In this case the distance also giveseffect proportional to the pulse distortion

32 Tropical Outdoor UWB Channel Measurements Fig-ure 10 shows the configuration of UWB pulse propagationmeasurements in an outdoor environment

This measurement setup consists of an array of watersprayers vector network analyzer rain gauge and TX and RXantennas The maximum range of our outdoor measurementwhich can be achieved is 10 meters with a variation of rainfall

Wireless Communications and Mobile Computing 5

times109

s21Frequency response s21Impulse response

2 4 6 80 141210

Frequency (Hz)

minus90

minus80

minus70

minus60

minus50

minus40

minus30

minus20

Am

plitu

de (d

B)

minus6

minus4

minus2

0

2

4

6

Am

plitu

de (s

minus1)

50 15 20 2510 30

Time (ns)

times10minus3

Figure 6 Log periodic antenna characteristics

intensity from 0 to 200mmh The device used in outdoorUWB channel measurement consists of the following

(1) Vector Network Analyzer (VNA) 0ndash13GHz(2) Array of water sprayers as a tropical rain simulator

that has intensity control to simulate different rainfallintensities 0 20 50 100 150 and 200mmh

(3) Rain gauge a device for measuring rainfall intensity(4) A pair of 1ndash13GHz UWB antennas as the photograph

in Figure 11 and their frequency and time domaincharacteristics as in Figure 12

321 Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 4 Meters Tropical outdoor channel measurementswere performed using the frequency domain approach as 11987821parameter To display the tropical outdoor channel impulseresponse in time domain the measured 11987821 parameter isthen processed by inverse Fourier transform using MATLABsoftware Figure 13 is the result of the channel impulseresponsemeasurements of tropical outdoor band 1ndash13GHz atdifferent rainfall intensity for TX and RX distances at 119889 = 4meters before and after deconvolution and noise filtering

Deconvolution process conducted on raw impulse re-sponse data is intended to eliminate the distortion effectsof TX and RX antennas To eliminate the noise from theraw data we used simple filtering with a moving averagefilter From Figure 13 we can see that as the rainfall intensitybecomes greater then the impulse responsewill be broadenedand more delayed and its amplitude will reduce In this caseat 119889 = 4 meters the influence of rainfall intensity is not toolarge so the impulse response of the tropical outdoor channelalmost coincides

322Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 10 Meters In our second measurement of tropical

outdoor UWB channel we set the distance between theantenna TX and RX antenna at 10 meters By comparingthe measurement results of two different distances 119889 it isexpected to see the effect of distance to the channel impulseresponse

Figure 14 shows that influence of rain intensity on thedistance 119889 = 10 meters is higher than the measurementresult at 119889 = 4 meters The impulse response of tropicaloutdoor UWB channel at very high rainfall (200mmh) hasamplitude shrinking so the impulse response width and ashift towards the main axis become larger than when thereis no rain (0mmh)

When we compare the results of numerical simulationand measurement results of the channel impulse responsesas Figures 8 9 13 and 14 we see that there is a strong corre-spondence between themeasurement results with simulationresults both for the pulse broadening the time shifted andthe amplitude reduction of impulse responses

The curves in Figures 15 16 and 17 consecutively quanti-tatively showed us pulse broadening the time shifted and theamplitude reduction of impulse responses at distance 119889 = 4and 119889 = 10 meters as a function of rainfall intensity

The three curves confirmed that the range and variationof rainfall intensity impact on pulse broadening the timeshifted and the amplitude reduction of impulse respons-es

33 Quantification of the Tropical Atmosphere Effect on UWB-Based 5G Performance In this scenario UWB-based 5Gsystems is assumed to have 500MBps with antipodal modu-lation for outdoor applications at tropical areas The UWB-based 5G system operates at 31ndash106GHz for achieving75 GHz with very low output power density

331 BER Performance of Matched Filter-Based Receiver withIdeal Antenna Figure 18 presents the BER performance of

6 Wireless Communications and Mobile Computing

minus50

minus40

minus30

minus20

minus10

0

(Deg

ree

km)

0 4 6 82 12 14 16 18 2010

Frequency (GHz)

4 6 82 12 14 16 18 2010

Frequency (GHz)

0mmh20mmh50mmh

0mmh20mmh50mmh

100mmh150mmh200 mmh

100mmh150mmh200 mmh

0

2

4

(dB

km)

6

8

10

12

14

outdoor UWB channelPhase shiedkm of 1ndash13 GHz tropical

Attenuationkm of 1ndash13 GHz tropical outdoor UWB channel

Figure 7 Magnitude and phase response of tropical outdoor UWBchannel at 1ndash13GHz band

UWB-based 5G system using matched filter-based receiverwith ideal antenna at 10 meter distance and bitrate 500Mbpsfor several of rainfall intensities From this figure we can seethat the BER performance curve decreases with increasingrainfall intensity which occurs along the path between the TXand RX

At 10minus6 BER performance the SNR requirements mustbe worth 5 8 12 16 175 and 18 dB for rainfall intensityconditions respectively 0 20 50 100 150 and 200mmh Inother words for keeping 10minus6 BER performance continuously

4

3

2

1

0

minus1

minus23 302 304 306 308 31

times10minus4

times10minus9

Volta

ge (v

olt)

Time (seconds)

Simulated impulse response of outdoord = 4 mtropical UWB channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

Figure 8 Simulated impulse response of tropical outdoor UWBchannel on 119889 = 4m

4

3

2

1

0

minus1

minus23

times10minus4

Volta

ge (v

olt)

302 304 306 308 31

times10minus9Time (seconds)

Simulated impulse response of outdoor

0mmh20mmh50mmh

100mmh150mmh200 mmh

d = 10 mtropical UWB channel

Figure 9 Channel impulse response of tropical outdoor UWB on119889 = 10m

in various conditions of rain the required fading margin isminimum 13 dB

Meanwhile if the benchmark performance using 119877001rainfall intensity is 120mmh for Bandung the requiredfading margin is 11 dB The BER curves in Figure 18 alsoshow that at fixed SNR conditions such as 5 dB then theBER performances are respectively 10minus6 10minus4 10minus3 and

Wireless Communications and Mobile Computing 7

Water

Antenna 1

Antenna 2

Rain intensitycontrollerVNA 0ndash13 GHz

sprayer

Rain gauge

Figure 10 Tropical outdoor channel measurement setup

Figure 11 Photograph of antenna used for UWB channel measure-ments

10minus2 for rainfall intensity at 0mmh 20mmh 50mmh and100mmh

332 BER Performance of Correlator-Based Receiver withIdeal Antenna Here as in Figure 19 the BER performanceof UWB system is using correlator-based receiver with idealantenna at 10meters distance and bitrate 500Mbps for severalof rainfall intensities From this figure we see that BER curvesdecrease with increasing rainfall intensity which occurs alongthe path between the TX and RX At 10minus6 BER performanceSNR requirements should be worth 7 10 14 18 20 and22 dB for rainfall intensity conditions respectively 0 2050 100 150 and 200mmh In other words to obtain theBERperformance 10minus6 continuously the necessary due fadingmargin is minimum 15 dB

BER curves at Figure 19 also show that at fixed SNR con-ditions such as 7 dB the BER then respectively is 10minus6 10minus510minus3 and 5times10minus1 for rainfall 0mmh 20mmh 50mmh and100mmh Comparing the BER performance curve betweenmatched filter and correlator-based receiver we can be seethat matched filter is 3ndash5 dB better than correlator-basedreceiver

333 BER Performance by Tropical Outdoor Channel andRealistic UWB Antenna The simulation results of BER per-formance evaluation of tropical outdoor channel with realis-tic antenna can be seen in Figures 20 and 21 with matchedfilter and correlator-based receiver respectively From thecurves in Figure 20 we can see that the UWB systemperformance is strongly influenced by the transient responsesof antenna and tropical outdoor channel In the matchedfilter-based receiver the use of realistic UWB antenna causesa decrease of 8-9 dB SNR while the correlator-based receiverdecreases SNR falls by 9-10 dB

34 UWB-Based 5G Bit Rate Reduction due to Tropical Out-door UWB Channel and Dispersive Antenna The effects ofrainfall intensity and the dispersive antenna to a reduction inbitrate of UWB communication system is summarized as inFigure 22 The specifications of UWB system are BER at 10minus6maintained bandwidth of 75 GHz and bitrate in additivewhite Gaussian noise (AWGN) condition at 500Mbps and 10meters distance

From Figure 22 we also can see that the intensity ofrainfall has a direct impact on the reduction in bitrate ofUWBcommunication systems The higher the rainfall the greaterthe reduction in data rate for all scenarios In an ideal scenariowith ideal antenna at rainfall intensity 200mmh the bitratewent down from 500Mbps (without rain) to 25Mbps for thematched filter and 15Mbps for the correlator-based receiverMeanwhile in realistic antenna scenarios at rainfall intensity200mmh the bitrate declined from 50Mbps (without rain)to 2Mbps for matched filter and 1Mbps for the correlator-based receiver

35 Adaptive Nonlinear Phase Equalizer Theproposed adap-tive nonlinear phase equalizer is used for mitigating thedistortions due to tropical outdoor channel and comes fromdispersive antennaThe target performance criteria of UWB-based 5G system for outdoor applications are using antipo-dal modulation operating frequency from 31 to 106GHzrequired SNR set to 10 dB for 119877 = 500Mbps power marginprovided as 5 dBminimumBER 10minus6 with availability 9999

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

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RotatingMachinery

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Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

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DistributedSensor Networks

International Journal of

4 Wireless Communications and Mobile Computing

Pulse in

Pulse out

Allpass IIR FIR

Channel estimator

Outdoor tropical

angHH

(H)＝ＢＨＨＦ + ＨＮＨＨ

Figure 4 Block diagram of proposed adaptive nonlinear phaseequalizer

0mmh120 mmh

200 400 600 800 1000 1200 1400 1600 1800 20000

minus1

minus05

0

05

1

Am

plitu

de (V

olt)

UWB pulse waveforms at outdoor tropical channel

Nth sample

Figure 5 Pulse shapes in a tropical outdoor UWB channel

with a dispersive UWB antenna system The rainfall rateused in this simulation is 119877001 of Bandung [16] the antennaselected is Log Periodic antenna which has bandwidth at2ndash8GHz [17] It is assumed that the distance between TXand RX is 10-meter long A Gaussian 01333 ns pulse shapesafter passing through the tropical outdoor UWB channel at0mmh and 120mmh and can be seen in Figure 5

Antenna used in this simulation is a Log Periodic antennawith wide bandwidth but has a dispersive impulse responseAs in [17] Log Periodic is one of antenna classes which havewide bandwidth and dispersive impulse response Frequencyand time domain characteristics of the 2ndash8GHz Log Periodicantenna can be seen in Figure 6

3 Results and Discussion

31 Characterization of Tropical Outdoor UWB Channel Thenumerical simulation results of the attenuation coefficient perkm and phase coefficient per km [18] can be seen in Figure 7When the distance between TX and RX is known then by

using the curve in Figure 7 we can obtain the magnituderesponse and the phase response of the tropical outdoorUWB channel

A transfer function of a tropical outdoor UWB channelcan then be calculated by combining the magnitude andphase responses as a function of frequency and rainfallintensity at 0 20 50 100 150 and 200mmh And by usingthe inverse Fourier transform we can determine the channelimpulse response

In this research author used short range of tropicaloutdoor communication model for both 4-meter and 10-meter distanceThe reason behind choosing these short rangecomes from the fact that our rain simulator facility asdescribed on Section 32 has maximum length of about 10meter Due to its rain attenuation proportionality propertiesto range our short range simulation andmeasurement resultswill lead us to estimate the rain effects for longer range as 5Grealistic applications

311 Numerical Simulation Results of Impulse Response ofTropical Outdoor UWB Channel at 119889 = 4 Meter Figure 8 isnumerical simulation results of the channel impulse responseof tropical outdoor at 1ndash13GHz band as a function of onfrequency on a variety of rainfall intensity for TX and RXdistance 119889 = 4 meters

From Figure 8 it can be seen that as the rainfall intensitybecomes greater then the impulse response will be morebroadened and delayed and its amplitude will be reducedHowever at distance between TX and RX antenna 119889 = 4meters the influence of rainfall intensity is small enough

312 Numerical Simulation Results of Impulse Response ofTropical Outdoor UWB Channel at 119889 = 10 Meters In oursecond calculation of impulse response of tropical outdoorUWB channel we assumed that the distance between theTX and RX antenna is 10 meters By comparing the resultsof calculations on two different distances d it is expected tosee the effect of distance on the impulse response profilesFigure 9 shows that at distance 119889 = 10 meters the pulsedistortion is higher than at 119889 = 4 meters

At very high rainfall intensity (200mmh) the impulseresponse has amplitude shrinking more broadening anddelay

From the numerical results at a distance of 119889 = 4m and119889 = 10m as shown in Figures 8 and 9 we may conclude thatthe intensity of tropical rainfall affects the changing shapeof the channel impulse response distortion which occurredwith an increasing delay amplitude reduction and pulseduration broadening In this case the distance also giveseffect proportional to the pulse distortion

32 Tropical Outdoor UWB Channel Measurements Fig-ure 10 shows the configuration of UWB pulse propagationmeasurements in an outdoor environment

This measurement setup consists of an array of watersprayers vector network analyzer rain gauge and TX and RXantennas The maximum range of our outdoor measurementwhich can be achieved is 10 meters with a variation of rainfall

Wireless Communications and Mobile Computing 5

times109

s21Frequency response s21Impulse response

2 4 6 80 141210

Frequency (Hz)

minus90

minus80

minus70

minus60

minus50

minus40

minus30

minus20

Am

plitu

de (d

B)

minus6

minus4

minus2

0

2

4

6

Am

plitu

de (s

minus1)

50 15 20 2510 30

Time (ns)

times10minus3

Figure 6 Log periodic antenna characteristics

intensity from 0 to 200mmh The device used in outdoorUWB channel measurement consists of the following

(1) Vector Network Analyzer (VNA) 0ndash13GHz(2) Array of water sprayers as a tropical rain simulator

that has intensity control to simulate different rainfallintensities 0 20 50 100 150 and 200mmh

(3) Rain gauge a device for measuring rainfall intensity(4) A pair of 1ndash13GHz UWB antennas as the photograph

in Figure 11 and their frequency and time domaincharacteristics as in Figure 12

321 Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 4 Meters Tropical outdoor channel measurementswere performed using the frequency domain approach as 11987821parameter To display the tropical outdoor channel impulseresponse in time domain the measured 11987821 parameter isthen processed by inverse Fourier transform using MATLABsoftware Figure 13 is the result of the channel impulseresponsemeasurements of tropical outdoor band 1ndash13GHz atdifferent rainfall intensity for TX and RX distances at 119889 = 4meters before and after deconvolution and noise filtering

Deconvolution process conducted on raw impulse re-sponse data is intended to eliminate the distortion effectsof TX and RX antennas To eliminate the noise from theraw data we used simple filtering with a moving averagefilter From Figure 13 we can see that as the rainfall intensitybecomes greater then the impulse responsewill be broadenedand more delayed and its amplitude will reduce In this caseat 119889 = 4 meters the influence of rainfall intensity is not toolarge so the impulse response of the tropical outdoor channelalmost coincides

322Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 10 Meters In our second measurement of tropical

outdoor UWB channel we set the distance between theantenna TX and RX antenna at 10 meters By comparingthe measurement results of two different distances 119889 it isexpected to see the effect of distance to the channel impulseresponse

Figure 14 shows that influence of rain intensity on thedistance 119889 = 10 meters is higher than the measurementresult at 119889 = 4 meters The impulse response of tropicaloutdoor UWB channel at very high rainfall (200mmh) hasamplitude shrinking so the impulse response width and ashift towards the main axis become larger than when thereis no rain (0mmh)

When we compare the results of numerical simulationand measurement results of the channel impulse responsesas Figures 8 9 13 and 14 we see that there is a strong corre-spondence between themeasurement results with simulationresults both for the pulse broadening the time shifted andthe amplitude reduction of impulse responses

The curves in Figures 15 16 and 17 consecutively quanti-tatively showed us pulse broadening the time shifted and theamplitude reduction of impulse responses at distance 119889 = 4and 119889 = 10 meters as a function of rainfall intensity

The three curves confirmed that the range and variationof rainfall intensity impact on pulse broadening the timeshifted and the amplitude reduction of impulse respons-es

33 Quantification of the Tropical Atmosphere Effect on UWB-Based 5G Performance In this scenario UWB-based 5Gsystems is assumed to have 500MBps with antipodal modu-lation for outdoor applications at tropical areas The UWB-based 5G system operates at 31ndash106GHz for achieving75 GHz with very low output power density

331 BER Performance of Matched Filter-Based Receiver withIdeal Antenna Figure 18 presents the BER performance of

6 Wireless Communications and Mobile Computing

minus50

minus40

minus30

minus20

minus10

0

(Deg

ree

km)

0 4 6 82 12 14 16 18 2010

Frequency (GHz)

4 6 82 12 14 16 18 2010

Frequency (GHz)

0mmh20mmh50mmh

0mmh20mmh50mmh

100mmh150mmh200 mmh

100mmh150mmh200 mmh

0

2

4

(dB

km)

6

8

10

12

14

outdoor UWB channelPhase shiedkm of 1ndash13 GHz tropical

Attenuationkm of 1ndash13 GHz tropical outdoor UWB channel

Figure 7 Magnitude and phase response of tropical outdoor UWBchannel at 1ndash13GHz band

UWB-based 5G system using matched filter-based receiverwith ideal antenna at 10 meter distance and bitrate 500Mbpsfor several of rainfall intensities From this figure we can seethat the BER performance curve decreases with increasingrainfall intensity which occurs along the path between the TXand RX

At 10minus6 BER performance the SNR requirements mustbe worth 5 8 12 16 175 and 18 dB for rainfall intensityconditions respectively 0 20 50 100 150 and 200mmh Inother words for keeping 10minus6 BER performance continuously

4

3

2

1

0

minus1

minus23 302 304 306 308 31

times10minus4

times10minus9

Volta

ge (v

olt)

Time (seconds)

Simulated impulse response of outdoord = 4 mtropical UWB channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

Figure 8 Simulated impulse response of tropical outdoor UWBchannel on 119889 = 4m

4

3

2

1

0

minus1

minus23

times10minus4

Volta

ge (v

olt)

302 304 306 308 31

times10minus9Time (seconds)

Simulated impulse response of outdoor

0mmh20mmh50mmh

100mmh150mmh200 mmh

d = 10 mtropical UWB channel

Figure 9 Channel impulse response of tropical outdoor UWB on119889 = 10m

in various conditions of rain the required fading margin isminimum 13 dB

Meanwhile if the benchmark performance using 119877001rainfall intensity is 120mmh for Bandung the requiredfading margin is 11 dB The BER curves in Figure 18 alsoshow that at fixed SNR conditions such as 5 dB then theBER performances are respectively 10minus6 10minus4 10minus3 and

Wireless Communications and Mobile Computing 7

Water

Antenna 1

Antenna 2

Rain intensitycontrollerVNA 0ndash13 GHz

sprayer

Rain gauge

Figure 10 Tropical outdoor channel measurement setup

Figure 11 Photograph of antenna used for UWB channel measure-ments

10minus2 for rainfall intensity at 0mmh 20mmh 50mmh and100mmh

332 BER Performance of Correlator-Based Receiver withIdeal Antenna Here as in Figure 19 the BER performanceof UWB system is using correlator-based receiver with idealantenna at 10meters distance and bitrate 500Mbps for severalof rainfall intensities From this figure we see that BER curvesdecrease with increasing rainfall intensity which occurs alongthe path between the TX and RX At 10minus6 BER performanceSNR requirements should be worth 7 10 14 18 20 and22 dB for rainfall intensity conditions respectively 0 2050 100 150 and 200mmh In other words to obtain theBERperformance 10minus6 continuously the necessary due fadingmargin is minimum 15 dB

BER curves at Figure 19 also show that at fixed SNR con-ditions such as 7 dB the BER then respectively is 10minus6 10minus510minus3 and 5times10minus1 for rainfall 0mmh 20mmh 50mmh and100mmh Comparing the BER performance curve betweenmatched filter and correlator-based receiver we can be seethat matched filter is 3ndash5 dB better than correlator-basedreceiver

333 BER Performance by Tropical Outdoor Channel andRealistic UWB Antenna The simulation results of BER per-formance evaluation of tropical outdoor channel with realis-tic antenna can be seen in Figures 20 and 21 with matchedfilter and correlator-based receiver respectively From thecurves in Figure 20 we can see that the UWB systemperformance is strongly influenced by the transient responsesof antenna and tropical outdoor channel In the matchedfilter-based receiver the use of realistic UWB antenna causesa decrease of 8-9 dB SNR while the correlator-based receiverdecreases SNR falls by 9-10 dB

34 UWB-Based 5G Bit Rate Reduction due to Tropical Out-door UWB Channel and Dispersive Antenna The effects ofrainfall intensity and the dispersive antenna to a reduction inbitrate of UWB communication system is summarized as inFigure 22 The specifications of UWB system are BER at 10minus6maintained bandwidth of 75 GHz and bitrate in additivewhite Gaussian noise (AWGN) condition at 500Mbps and 10meters distance

From Figure 22 we also can see that the intensity ofrainfall has a direct impact on the reduction in bitrate ofUWBcommunication systems The higher the rainfall the greaterthe reduction in data rate for all scenarios In an ideal scenariowith ideal antenna at rainfall intensity 200mmh the bitratewent down from 500Mbps (without rain) to 25Mbps for thematched filter and 15Mbps for the correlator-based receiverMeanwhile in realistic antenna scenarios at rainfall intensity200mmh the bitrate declined from 50Mbps (without rain)to 2Mbps for matched filter and 1Mbps for the correlator-based receiver

35 Adaptive Nonlinear Phase Equalizer Theproposed adap-tive nonlinear phase equalizer is used for mitigating thedistortions due to tropical outdoor channel and comes fromdispersive antennaThe target performance criteria of UWB-based 5G system for outdoor applications are using antipo-dal modulation operating frequency from 31 to 106GHzrequired SNR set to 10 dB for 119877 = 500Mbps power marginprovided as 5 dBminimumBER 10minus6 with availability 9999

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

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RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

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DistributedSensor Networks

International Journal of

Wireless Communications and Mobile Computing 5

times109

s21Frequency response s21Impulse response

2 4 6 80 141210

Frequency (Hz)

minus90

minus80

minus70

minus60

minus50

minus40

minus30

minus20

Am

plitu

de (d

B)

minus6

minus4

minus2

0

2

4

6

Am

plitu

de (s

minus1)

50 15 20 2510 30

Time (ns)

times10minus3

Figure 6 Log periodic antenna characteristics

intensity from 0 to 200mmh The device used in outdoorUWB channel measurement consists of the following

(1) Vector Network Analyzer (VNA) 0ndash13GHz(2) Array of water sprayers as a tropical rain simulator

that has intensity control to simulate different rainfallintensities 0 20 50 100 150 and 200mmh

(3) Rain gauge a device for measuring rainfall intensity(4) A pair of 1ndash13GHz UWB antennas as the photograph

in Figure 11 and their frequency and time domaincharacteristics as in Figure 12

321 Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 4 Meters Tropical outdoor channel measurementswere performed using the frequency domain approach as 11987821parameter To display the tropical outdoor channel impulseresponse in time domain the measured 11987821 parameter isthen processed by inverse Fourier transform using MATLABsoftware Figure 13 is the result of the channel impulseresponsemeasurements of tropical outdoor band 1ndash13GHz atdifferent rainfall intensity for TX and RX distances at 119889 = 4meters before and after deconvolution and noise filtering

Deconvolution process conducted on raw impulse re-sponse data is intended to eliminate the distortion effectsof TX and RX antennas To eliminate the noise from theraw data we used simple filtering with a moving averagefilter From Figure 13 we can see that as the rainfall intensitybecomes greater then the impulse responsewill be broadenedand more delayed and its amplitude will reduce In this caseat 119889 = 4 meters the influence of rainfall intensity is not toolarge so the impulse response of the tropical outdoor channelalmost coincides

322Measurement Results of Tropical Outdoor UWBChannelfor 119889 = 10 Meters In our second measurement of tropical

outdoor UWB channel we set the distance between theantenna TX and RX antenna at 10 meters By comparingthe measurement results of two different distances 119889 it isexpected to see the effect of distance to the channel impulseresponse

Figure 14 shows that influence of rain intensity on thedistance 119889 = 10 meters is higher than the measurementresult at 119889 = 4 meters The impulse response of tropicaloutdoor UWB channel at very high rainfall (200mmh) hasamplitude shrinking so the impulse response width and ashift towards the main axis become larger than when thereis no rain (0mmh)

When we compare the results of numerical simulationand measurement results of the channel impulse responsesas Figures 8 9 13 and 14 we see that there is a strong corre-spondence between themeasurement results with simulationresults both for the pulse broadening the time shifted andthe amplitude reduction of impulse responses

The curves in Figures 15 16 and 17 consecutively quanti-tatively showed us pulse broadening the time shifted and theamplitude reduction of impulse responses at distance 119889 = 4and 119889 = 10 meters as a function of rainfall intensity

The three curves confirmed that the range and variationof rainfall intensity impact on pulse broadening the timeshifted and the amplitude reduction of impulse respons-es

33 Quantification of the Tropical Atmosphere Effect on UWB-Based 5G Performance In this scenario UWB-based 5Gsystems is assumed to have 500MBps with antipodal modu-lation for outdoor applications at tropical areas The UWB-based 5G system operates at 31ndash106GHz for achieving75 GHz with very low output power density

331 BER Performance of Matched Filter-Based Receiver withIdeal Antenna Figure 18 presents the BER performance of

6 Wireless Communications and Mobile Computing

minus50

minus40

minus30

minus20

minus10

0

(Deg

ree

km)

0 4 6 82 12 14 16 18 2010

Frequency (GHz)

4 6 82 12 14 16 18 2010

Frequency (GHz)

0mmh20mmh50mmh

0mmh20mmh50mmh

100mmh150mmh200 mmh

100mmh150mmh200 mmh

0

2

4

(dB

km)

6

8

10

12

14

outdoor UWB channelPhase shiedkm of 1ndash13 GHz tropical

Attenuationkm of 1ndash13 GHz tropical outdoor UWB channel

Figure 7 Magnitude and phase response of tropical outdoor UWBchannel at 1ndash13GHz band

UWB-based 5G system using matched filter-based receiverwith ideal antenna at 10 meter distance and bitrate 500Mbpsfor several of rainfall intensities From this figure we can seethat the BER performance curve decreases with increasingrainfall intensity which occurs along the path between the TXand RX

At 10minus6 BER performance the SNR requirements mustbe worth 5 8 12 16 175 and 18 dB for rainfall intensityconditions respectively 0 20 50 100 150 and 200mmh Inother words for keeping 10minus6 BER performance continuously

4

3

2

1

0

minus1

minus23 302 304 306 308 31

times10minus4

times10minus9

Volta

ge (v

olt)

Time (seconds)

Simulated impulse response of outdoord = 4 mtropical UWB channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

Figure 8 Simulated impulse response of tropical outdoor UWBchannel on 119889 = 4m

4

3

2

1

0

minus1

minus23

times10minus4

Volta

ge (v

olt)

302 304 306 308 31

times10minus9Time (seconds)

Simulated impulse response of outdoor

0mmh20mmh50mmh

100mmh150mmh200 mmh

d = 10 mtropical UWB channel

Figure 9 Channel impulse response of tropical outdoor UWB on119889 = 10m

in various conditions of rain the required fading margin isminimum 13 dB

Meanwhile if the benchmark performance using 119877001rainfall intensity is 120mmh for Bandung the requiredfading margin is 11 dB The BER curves in Figure 18 alsoshow that at fixed SNR conditions such as 5 dB then theBER performances are respectively 10minus6 10minus4 10minus3 and

Wireless Communications and Mobile Computing 7

Water

Antenna 1

Antenna 2

Rain intensitycontrollerVNA 0ndash13 GHz

sprayer

Rain gauge

Figure 10 Tropical outdoor channel measurement setup

Figure 11 Photograph of antenna used for UWB channel measure-ments

10minus2 for rainfall intensity at 0mmh 20mmh 50mmh and100mmh

332 BER Performance of Correlator-Based Receiver withIdeal Antenna Here as in Figure 19 the BER performanceof UWB system is using correlator-based receiver with idealantenna at 10meters distance and bitrate 500Mbps for severalof rainfall intensities From this figure we see that BER curvesdecrease with increasing rainfall intensity which occurs alongthe path between the TX and RX At 10minus6 BER performanceSNR requirements should be worth 7 10 14 18 20 and22 dB for rainfall intensity conditions respectively 0 2050 100 150 and 200mmh In other words to obtain theBERperformance 10minus6 continuously the necessary due fadingmargin is minimum 15 dB

BER curves at Figure 19 also show that at fixed SNR con-ditions such as 7 dB the BER then respectively is 10minus6 10minus510minus3 and 5times10minus1 for rainfall 0mmh 20mmh 50mmh and100mmh Comparing the BER performance curve betweenmatched filter and correlator-based receiver we can be seethat matched filter is 3ndash5 dB better than correlator-basedreceiver

333 BER Performance by Tropical Outdoor Channel andRealistic UWB Antenna The simulation results of BER per-formance evaluation of tropical outdoor channel with realis-tic antenna can be seen in Figures 20 and 21 with matchedfilter and correlator-based receiver respectively From thecurves in Figure 20 we can see that the UWB systemperformance is strongly influenced by the transient responsesof antenna and tropical outdoor channel In the matchedfilter-based receiver the use of realistic UWB antenna causesa decrease of 8-9 dB SNR while the correlator-based receiverdecreases SNR falls by 9-10 dB

34 UWB-Based 5G Bit Rate Reduction due to Tropical Out-door UWB Channel and Dispersive Antenna The effects ofrainfall intensity and the dispersive antenna to a reduction inbitrate of UWB communication system is summarized as inFigure 22 The specifications of UWB system are BER at 10minus6maintained bandwidth of 75 GHz and bitrate in additivewhite Gaussian noise (AWGN) condition at 500Mbps and 10meters distance

From Figure 22 we also can see that the intensity ofrainfall has a direct impact on the reduction in bitrate ofUWBcommunication systems The higher the rainfall the greaterthe reduction in data rate for all scenarios In an ideal scenariowith ideal antenna at rainfall intensity 200mmh the bitratewent down from 500Mbps (without rain) to 25Mbps for thematched filter and 15Mbps for the correlator-based receiverMeanwhile in realistic antenna scenarios at rainfall intensity200mmh the bitrate declined from 50Mbps (without rain)to 2Mbps for matched filter and 1Mbps for the correlator-based receiver

35 Adaptive Nonlinear Phase Equalizer Theproposed adap-tive nonlinear phase equalizer is used for mitigating thedistortions due to tropical outdoor channel and comes fromdispersive antennaThe target performance criteria of UWB-based 5G system for outdoor applications are using antipo-dal modulation operating frequency from 31 to 106GHzrequired SNR set to 10 dB for 119877 = 500Mbps power marginprovided as 5 dBminimumBER 10minus6 with availability 9999

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

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RotatingMachinery

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Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

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Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

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Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

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Navigation and Observation

International Journal of

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DistributedSensor Networks

International Journal of

6 Wireless Communications and Mobile Computing

minus50

minus40

minus30

minus20

minus10

0

(Deg

ree

km)

0 4 6 82 12 14 16 18 2010

Frequency (GHz)

4 6 82 12 14 16 18 2010

Frequency (GHz)

0mmh20mmh50mmh

0mmh20mmh50mmh

100mmh150mmh200 mmh

100mmh150mmh200 mmh

0

2

4

(dB

km)

6

8

10

12

14

outdoor UWB channelPhase shiedkm of 1ndash13 GHz tropical

Attenuationkm of 1ndash13 GHz tropical outdoor UWB channel

Figure 7 Magnitude and phase response of tropical outdoor UWBchannel at 1ndash13GHz band

UWB-based 5G system using matched filter-based receiverwith ideal antenna at 10 meter distance and bitrate 500Mbpsfor several of rainfall intensities From this figure we can seethat the BER performance curve decreases with increasingrainfall intensity which occurs along the path between the TXand RX

At 10minus6 BER performance the SNR requirements mustbe worth 5 8 12 16 175 and 18 dB for rainfall intensityconditions respectively 0 20 50 100 150 and 200mmh Inother words for keeping 10minus6 BER performance continuously

4

3

2

1

0

minus1

minus23 302 304 306 308 31

times10minus4

times10minus9

Volta

ge (v

olt)

Time (seconds)

Simulated impulse response of outdoord = 4 mtropical UWB channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

Figure 8 Simulated impulse response of tropical outdoor UWBchannel on 119889 = 4m

4

3

2

1

0

minus1

minus23

times10minus4

Volta

ge (v

olt)

302 304 306 308 31

times10minus9Time (seconds)

Simulated impulse response of outdoor

0mmh20mmh50mmh

100mmh150mmh200 mmh

d = 10 mtropical UWB channel

Figure 9 Channel impulse response of tropical outdoor UWB on119889 = 10m

in various conditions of rain the required fading margin isminimum 13 dB

Meanwhile if the benchmark performance using 119877001rainfall intensity is 120mmh for Bandung the requiredfading margin is 11 dB The BER curves in Figure 18 alsoshow that at fixed SNR conditions such as 5 dB then theBER performances are respectively 10minus6 10minus4 10minus3 and

Wireless Communications and Mobile Computing 7

Water

Antenna 1

Antenna 2

Rain intensitycontrollerVNA 0ndash13 GHz

sprayer

Rain gauge

Figure 10 Tropical outdoor channel measurement setup

Figure 11 Photograph of antenna used for UWB channel measure-ments

10minus2 for rainfall intensity at 0mmh 20mmh 50mmh and100mmh

332 BER Performance of Correlator-Based Receiver withIdeal Antenna Here as in Figure 19 the BER performanceof UWB system is using correlator-based receiver with idealantenna at 10meters distance and bitrate 500Mbps for severalof rainfall intensities From this figure we see that BER curvesdecrease with increasing rainfall intensity which occurs alongthe path between the TX and RX At 10minus6 BER performanceSNR requirements should be worth 7 10 14 18 20 and22 dB for rainfall intensity conditions respectively 0 2050 100 150 and 200mmh In other words to obtain theBERperformance 10minus6 continuously the necessary due fadingmargin is minimum 15 dB

BER curves at Figure 19 also show that at fixed SNR con-ditions such as 7 dB the BER then respectively is 10minus6 10minus510minus3 and 5times10minus1 for rainfall 0mmh 20mmh 50mmh and100mmh Comparing the BER performance curve betweenmatched filter and correlator-based receiver we can be seethat matched filter is 3ndash5 dB better than correlator-basedreceiver

333 BER Performance by Tropical Outdoor Channel andRealistic UWB Antenna The simulation results of BER per-formance evaluation of tropical outdoor channel with realis-tic antenna can be seen in Figures 20 and 21 with matchedfilter and correlator-based receiver respectively From thecurves in Figure 20 we can see that the UWB systemperformance is strongly influenced by the transient responsesof antenna and tropical outdoor channel In the matchedfilter-based receiver the use of realistic UWB antenna causesa decrease of 8-9 dB SNR while the correlator-based receiverdecreases SNR falls by 9-10 dB

34 UWB-Based 5G Bit Rate Reduction due to Tropical Out-door UWB Channel and Dispersive Antenna The effects ofrainfall intensity and the dispersive antenna to a reduction inbitrate of UWB communication system is summarized as inFigure 22 The specifications of UWB system are BER at 10minus6maintained bandwidth of 75 GHz and bitrate in additivewhite Gaussian noise (AWGN) condition at 500Mbps and 10meters distance

From Figure 22 we also can see that the intensity ofrainfall has a direct impact on the reduction in bitrate ofUWBcommunication systems The higher the rainfall the greaterthe reduction in data rate for all scenarios In an ideal scenariowith ideal antenna at rainfall intensity 200mmh the bitratewent down from 500Mbps (without rain) to 25Mbps for thematched filter and 15Mbps for the correlator-based receiverMeanwhile in realistic antenna scenarios at rainfall intensity200mmh the bitrate declined from 50Mbps (without rain)to 2Mbps for matched filter and 1Mbps for the correlator-based receiver

35 Adaptive Nonlinear Phase Equalizer Theproposed adap-tive nonlinear phase equalizer is used for mitigating thedistortions due to tropical outdoor channel and comes fromdispersive antennaThe target performance criteria of UWB-based 5G system for outdoor applications are using antipo-dal modulation operating frequency from 31 to 106GHzrequired SNR set to 10 dB for 119877 = 500Mbps power marginprovided as 5 dBminimumBER 10minus6 with availability 9999

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

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DistributedSensor Networks

International Journal of

Wireless Communications and Mobile Computing 7

Water

Antenna 1

Antenna 2

Rain intensitycontrollerVNA 0ndash13 GHz

sprayer

Rain gauge

Figure 10 Tropical outdoor channel measurement setup

Figure 11 Photograph of antenna used for UWB channel measure-ments

10minus2 for rainfall intensity at 0mmh 20mmh 50mmh and100mmh

332 BER Performance of Correlator-Based Receiver withIdeal Antenna Here as in Figure 19 the BER performanceof UWB system is using correlator-based receiver with idealantenna at 10meters distance and bitrate 500Mbps for severalof rainfall intensities From this figure we see that BER curvesdecrease with increasing rainfall intensity which occurs alongthe path between the TX and RX At 10minus6 BER performanceSNR requirements should be worth 7 10 14 18 20 and22 dB for rainfall intensity conditions respectively 0 2050 100 150 and 200mmh In other words to obtain theBERperformance 10minus6 continuously the necessary due fadingmargin is minimum 15 dB

BER curves at Figure 19 also show that at fixed SNR con-ditions such as 7 dB the BER then respectively is 10minus6 10minus510minus3 and 5times10minus1 for rainfall 0mmh 20mmh 50mmh and100mmh Comparing the BER performance curve betweenmatched filter and correlator-based receiver we can be seethat matched filter is 3ndash5 dB better than correlator-basedreceiver

333 BER Performance by Tropical Outdoor Channel andRealistic UWB Antenna The simulation results of BER per-formance evaluation of tropical outdoor channel with realis-tic antenna can be seen in Figures 20 and 21 with matchedfilter and correlator-based receiver respectively From thecurves in Figure 20 we can see that the UWB systemperformance is strongly influenced by the transient responsesof antenna and tropical outdoor channel In the matchedfilter-based receiver the use of realistic UWB antenna causesa decrease of 8-9 dB SNR while the correlator-based receiverdecreases SNR falls by 9-10 dB

34 UWB-Based 5G Bit Rate Reduction due to Tropical Out-door UWB Channel and Dispersive Antenna The effects ofrainfall intensity and the dispersive antenna to a reduction inbitrate of UWB communication system is summarized as inFigure 22 The specifications of UWB system are BER at 10minus6maintained bandwidth of 75 GHz and bitrate in additivewhite Gaussian noise (AWGN) condition at 500Mbps and 10meters distance

From Figure 22 we also can see that the intensity ofrainfall has a direct impact on the reduction in bitrate ofUWBcommunication systems The higher the rainfall the greaterthe reduction in data rate for all scenarios In an ideal scenariowith ideal antenna at rainfall intensity 200mmh the bitratewent down from 500Mbps (without rain) to 25Mbps for thematched filter and 15Mbps for the correlator-based receiverMeanwhile in realistic antenna scenarios at rainfall intensity200mmh the bitrate declined from 50Mbps (without rain)to 2Mbps for matched filter and 1Mbps for the correlator-based receiver

35 Adaptive Nonlinear Phase Equalizer Theproposed adap-tive nonlinear phase equalizer is used for mitigating thedistortions due to tropical outdoor channel and comes fromdispersive antennaThe target performance criteria of UWB-based 5G system for outdoor applications are using antipo-dal modulation operating frequency from 31 to 106GHzrequired SNR set to 10 dB for 119877 = 500Mbps power marginprovided as 5 dBminimumBER 10minus6 with availability 9999

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

8 Wireless Communications and Mobile Computing

minus25

minus30

minus35

minus40

minus45

minus500 2 4 6 8 10 12 14

Frequency (GHz)

Mag

nitu

de (d

B)

20

15

10

5

0

minus5

12 14 16 18 2 22 24

time (ns)

Volta

ge (m

icro

volt)

(S21) (s21) Frequency response of the antennas Impulse response of the antennas

Figure 12 Frequency and time domain characteristic of antenna used for UWB channel measurements

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Volta

ge (V

)

Time (seconds) times10minus9

times10minus6Measured impulse response of tropical outdoor

channel (Raw Data)

0mmh20mmh50mmh

100mmh150mmh200 mmh

(a)

Time (seconds) times10minus9

times10minus4Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

0mmh20mmh50mmh

100mmh150mmh200 mmh

outdoor channel

(b)

Figure 13 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 4meter

for rainfall 119877001 = 120mmh and the receiver based on bothmatched filter or correlator

In this scenario we proposed an adaptive nonlinear phaseequalizer based on allpass biquad IIR order 6 cascaded to FIRfilter order 6 The magnitude and phase responses of allpassbiquad IIR order 6 and its poleszeros structure are shown inFigures 23 and 24

351 BER Improvement of Matched Filter before and afterNonlinear Compensation The curve as in Figure 25 showsthe BER performance of matched filter-based receiver withand without nonlinear phase compensation The red portionof the graph states that the BER performances are under ourtechnical requirements (BER gt 10minus6)

From this figure we can see that improvement hasoccurred around 10 dB SNR compared to the BER perfor-mance of matched filter-based receiver without phase com-pensation Thus an UWB system with a minimum SNR10 dB and 5 dB fading margin can still be working well atBER 10minus6

In this case phase compensation is done due to thecontribution of rainfall intensity 120mmh but also doneon the nonlinearity phase response of antenna Thereforethe application of phase equalization on matched filter-basedreceiver can ensure theUWB systemworks on the availabilityof 9999 for the 1198770 01 = 120mmh at Bandung

As for rainfall above 120mmh BER performance fallsbelow the desired performance requirements However

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

Wireless Communications and Mobile Computing 9

2

0

minus2

minus4

minus6

minus812 122 124 126 128 13

Time (seconds) times10minus9

Measured impulse response of tropical outdoorVo

ltage

(V)

channel (Raw Data)

0mmh20mmh50mmh100mmh150mmh200 mmh

times10minus6

(a)

Time (seconds) times10minus9

Measured impulse response of tropical

296 298 3 302 304 306

minus2

minus1

0

1

2

3

Volta

ge (V

)

outdoor channel

0mmh20mmh50mmh

100mmh150mmh200 mmh

times10minus4

(b)

Figure 14 Measured impulse response before (a) and after (b) deconvolution and noise filtering at 119889 = 10 meters

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of pulse broadeningchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

0

0001

0002

0003

0004

0005

0006

0007

0008

0009

001

Pulse

bro

aden

ing

(nan

osec

onds

)

Simulation 10 mMeasured 10 m

Simulation 4mMeasured 4m

Figure 15 Simulated versus measured pulse broadening of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

rainfall intensity above 120mmh has an opportunity whichoccurs lt001 a year so that is not statistically signifi-cant

352 BER Improvement of Correlator before and after Non-linear Compensation The simulation of BER performanceimprovement by nonlinear phase compensator for correlator-based receiver can be seen in Figure 26

The BER curve as in Figure 26 shows that improve-ment has occurred around 10 dB SNR compared to the

0 20 40 60 80 100 120 140 160 180 200

Simulated versus measured impulse response

d = 4 m and d = 10 m in termschannel for

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

0

1

2

3

4

5

6

7

8

Pulse

tim

e shi

ing

(nan

osec

onds

)

times10minus3Of tropical outdoor

of time shiing

Simulation 10 mMeasured 10 m

Figure 16 Simulated versusmeasured pulse time shifting of tropicaloutdoor channel at 119889 = 4 meters and 119889 = 10 meters

performance of correlator-based UWB receiver withoutphase compensation

However for UWB systems with a minimum SNR and10 dB fadingmargin of 5 dB 10minus6 BER performance cannot bemaintained because the phase compensation is not enoughto overcome the performance degradation by dispersiveantenna and rainfall intensity 120mmh Correlator-basedreceiver with phase compensation can only achieve BERperformance 10minus4 In other words the correlator-based UWBreceiver does not meet the performance specifications thathave been required

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

10 Wireless Communications and Mobile Computing

Simulated versus measured impulse response of tropical outdoord = 4 m and d = 10 m in terms of amplitude reductionchannel for

0 20 40 60 80 100 120 140 160 180 200

Rainfall intensity (mmh)

Simulation 4mMeasured 4m

1

15

2

25

3

35

4

Am

plitu

de (1

00 m

icro

Volt)

Simulation 10 mMeasured 10 m

Figure 17 Simulated versusmeasured amplitude of tropical outdoorchannel at 119889 = 4 meters and 119889 = 10 meters

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh10 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 18 BER performance curves ofmatched filter-based receiverwith ideal antenna

4 Conclusions and Future Research Direction

Several important conclusions produced in this research areas follows

(1) The dynamics of tropical outdoor channel versus timeis strongly influenced by the atmosphere especiallythe rainfall components At a very high rainfallintensity (200mmh) a tropical outdoor channel willhave a large difference attenuation of low frequencycomponents with the highest frequency componentof the UWB band that is 95 dBkm In additionthe frequency components of the UWB signal spec-trum over the tropical outdoor channel will alsoshift in nonlinear phase by rain in its path compo-nents 03 Radkm at the same rainfall The results

minus40 minus30 minus20 minus10 0 10 20

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

SNR

100 mmh150mmh200 mmh

0mmh20 mmh50mmh

BER performance of antipodal signals atd = 10 mtropical outdoor

Figure 19 BER performance curves of correlator-based receiverwith ideal antenna

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

BER performance of MF receiver (at d = 10 m

(＝ＢＨＨＦ + ＨＮＨＨ)

＝ＢＨＨＦ + ＨＮＨＨ)

Figure 20 BER performance curves matched filter-based receiverwith realistic UWB antenna

of numerical simulations the channel measurementand mathematical models show the suitability oftropical UWB channel distortion causing a wideningof pulse duration the main axis and a shift amplitudereduction

(2) In no rain conditions a BER performance at 10minus6 canbe achievedwith the SNR 5 dB but at rainfall intensityat 200mmh BER deteriorated to 10minus2 for matchedfilter-based and for correlator-based falls to 5 times 10minus2Rainfall intensity of 200mmh can cause 15 dB loss ofUWB signal quality for matched filter and 19 dB forcorrelator-based receiver So in this case the optimalsystem based on matched filter has a 3ndash5 dB betterperformance than correlator-based for tropical areasThe rainfall intensity has also a direct impact on the

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

Wireless Communications and Mobile Computing 11

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6

BER

perfo

man

ce

minus40 minus30 minus20 minus10 0 10 20

SNR

0mmh20 mmh50mmh

100 mmh150mmh200 mmh

at d = 10 mBER performance of correlator (＝ＢＨＨＦ + ＨＮＨＨ)

Figure 21 BER performance curves correlator-based receiver withrealistic UWB antenna

150 200

Data rate reduction due to outdoor tropical

0

50

100

150

200

250

300

350

400

450

500

Dat

a rat

e (M

Bps)

50 1000

Rain Intensity (mmh)

antenna

antenna

＝ＢＨＨＦ + ＨＮＨＨ

－ + Ｃ＞Ｆ ＨＮＨＨ － + ＬＦＣＮＣＭＮＣ＝

ＩＬＬＦＮＩＬ + ＬＦＣＮＣＭＮＣ＝ＩＬＬＦＮＩＬ + Ｃ＞Ｆ ＨＮＨＨ

Figure 22 Bitrate reduction of UWB-based 5G system due totropical outdoor channel and the antenna effects

bitrate reduction on UWB communication systemsIn an ideal scenario with ideal antennas at rainfallintensity 200mmh bitrate of UWB communicationsystems will go down from 500Mbps (no rain) to25Mbps for the matched filter and 15Mbps for thecorrelator-based receivers Meanwhile in a realisticantenna scenario at rainfall intensity 200mmh thebitrate of UWB communication systems declinedfrom 50Mbps (no rain) to 2Mbps for matched filterand 1Mbps for the correlator-based receiver

Magnitude and phase response of phase equalizerwith All IIR order 6

10minus2

100

102

Mag

nitu

de

100 10110minus1

Frequency (rads)

minus200

minus100

0

100

200

Phas

e (de

gree

s)

100 10110minus1

Frequency (rads)

Figure 23 The magnitude and phase responses of proposed allpassIIR order 6

Poles and zeros of phase equalizer with All IIR order 6

minus1

minus05

0

05

1

Imag

inar

y pa

rt

0 1minus1 05 15minus05minus15

Real part

Figure 24 Poles and zeros structure of proposed Allpass IIR order6

(3) It can be known from the numerical simulation andmeasurement results of 1ndash13GHz tropical outdoorUWB channel that the pulse distortion is caused bythe nonlinearity of phase responses and the magni-tude response ruggedness of antenna and outdoortropical channel A proposed adaptive nonlinearphase equalizer with allpass IIR order 6 or morecascaded with a low-order FIR structure (gt6) can beused to compensate an accumulation of distortion bythe transmission channel and the antenna

Simulation results show that the 500MBps UWB-based 5G system performance using matched filter-based receiver at 10minus6 BER can still be maintained forthe 119877001 rainfall intensity or availability of 9999 In

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

12 Wireless Communications and Mobile Computing

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

d = 10 m withBER performance of MF receiver atproposed equalizer

Rain rate 120 mmh

Rain rate 120 mmh

Figure 25 BER performance of the matched filter-based receiverwith phase compensation

100

10minus1

10minus2

10minus3

10minus4

10minus5

10minus6minus40 minus30 minus20 minus10 0 10 20 30

BER

perfo

man

ce

SNR

Ideal

＞ＣＭＪＬＭＣＰ antennawith equalizer

without equalizer

+

＞ＣＭＪＬＭＣＰ antenna+

proposed equalizerd = 10 m withBER performance of correlator at

Rain rate 120 mmh

Rain rate 120 mmh

Figure 26 BER performance of the correlator-based receiver withphase compensation

addition the proposed nonlinear phase equalizer iscapable of providing improved UWB signal by 9 dBat 120mm rainfallh compared with the UWB systemwithout phase compensator These results make usconfident of bringing our future research to increasethe target bit rate by exploiting the massive MIMOtransceivers and using higher order modulation

In the near future we will perform field test of our1ndash13GHz 10 times 10 MIMO based on PXI-based NationalInstruments SDR for UWB-based 5G system application attropical environment Our field test activities will be reportedat the end of the year 2017 that is during rainy season inIndonesia

Conflicts of Interest

The author declares that he has no conflicts of interest

References

[1] B Van Lievenoogen ldquoInvestigation of the suaitability of ultraw-ideband in military scenariosrdquo Master Thesis Report Wirelessand Mobile Communciations Group Delft University of Tech-nology 2008

[2] N A Alsindi B Alavi and K Pahlavan ldquoMeasurement andmodeling of ultrawideband TOA-based ranging in indoor mul-tipath environmentsrdquo IEEE Transactions on Vehicular Technol-ogy vol 58 no 3 pp 1046ndash1058 2009

[3] J A N Noronha Ultrawideband channel sounding studies inoutdoor and outdoor-indoor environments [thesis] VirginiaPolytechnic Institute and State University Blacksburg Va USA2004

[4] L Rubio J Reig H Fernandez and V M Rodrigo-PenarrochaldquoExperimental UWB propagation channel path loss and time-dispersion characterization in a laboratory environmentrdquo Inter-national Journal of Antennas and Propagation vol 2013 ArticleID 350167 7 pages 2013

[5] C J Gibbins ldquoPropagation of very short pulses through theabsorptive and dispersive atmosphererdquo IEE Proceedings HMicrowaves Antennas and Propagation vol 137 no 5 pp 304ndash310 1990

[6] A Maitra M Dan A K Sen K Bhattacharyya and C KSarkar ldquoPropagation of very short pulses at millimeter wave-lengths through rain filled mediumrdquo International Journal ofInfrared and Millimeter Waves vol 14 no 3 pp 703ndash713 1993

[7] M ZWin F Ramirez-Mireles R A Scholtz andM A BarnesldquoUltra-wide bandwidth (UWB) signal propagation for outdoorwireless communicationsrdquo in Proceedings of the 47th IEEEVehicular Technology Conference vol 1 pp 251ndash255 May 1997

[8] B ScheersUltra-wideband ground penetrating radar with appli-cation to the detection of anti personnel landmines [PhD disser-tation] Laboratoire DrsquoHyperfrequences Universite CatholiqueDe Louvain Ottignies-Louvain-la-Neuve Belgium 2001

[9] M Ghavami L B Michael and R dan KohnoUltra WidebandSignals and Systems in Communication Engineering JohnWileyamp Sons New York NY USA 2nd edition 2007

[10] H C V D Hulst Light Scattering by Small Particles JohnWileyamp Sons New York NY USA 1957

[11] L J Ippolito A Summary of Propagation Impairments on10ndash100GHz Satelite Links with Techniques Propagation EffectsHandbook for Satellite Systems Design NASA Reference Publi-cation 1082(04) NASA 1989

[12] H J Liebe G A Hufford and T Manabe ldquoA model for thecomplex permittivity of water at frequencies below 1 THzrdquoInternational Journal of Infrared and Millimeter Waves vol 12no 7 pp 659ndash675 1991

[13] K Teplee ldquoBER performance of UWB communications withmatched filter and correlation receiversrdquo in Proceeding of theECTI International Conference 2007

[14] Z N Chen X H Wu H F Li N Yang and M Y W ChialdquoConsiderations for source pulses and antennas in UWB radiosystemsrdquo IEEE Transactions on Antennas and Propagation vol52 no 7 pp 1739ndash1748 2004

[15] J S Abel ldquoRobust design of very high-order allpass dispersionfiltersrdquo in Proceedings of the 9th International Conference on

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

Wireless Communications and Mobile Computing 13

Digital Audio Effects (DAFx rsquo06) Montreal Canada September2006

[16] J Suryana S Utoro K Tanaka K Igarashi and M Iida ldquoTwoyears characterization of concurrent Ku-band rain attenuationand tropospheric scintillation in Bandung Indonesia usingJCSAT3rdquo in Proceedings of the 5th International Conference onInformation Communications and Signal Processing (ICICS rsquo05)pp 1585ndash1589 December 2005

[17] S Slicul Ultrawideband antena characterization and measure-ments [PhD dissertation] Electrical Engineering VirginiaTech 2004

[18] J Suryana A B Suksmono Sugihartono and A KurniawanldquoNumerical and experimental investigations of a tropical out-door UWB channel characteristics for short pulse transmis-sionrdquo in Proceedings of the PIERS Tokyo Japan August 2006

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Active and Passive Electronic Components

Control Scienceand Engineering

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

International Journal of

RotatingMachinery

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporation httpwwwhindawicom

Journal of

Volume 201

Submit your manuscripts athttpswwwhindawicom

VLSI Design

Hindawi Publishing Corporationhttpwwwhindawicom Volume 201

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Shock and Vibration

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawi Publishing Corporation httpwwwhindawicom

Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Navigation and Observation

International Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

DistributedSensor Networks

International Journal of