Charles Msc Defence

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IEEE 802.11p Vehicle to Vehicle

(V2V) Communication

Charles Joseph OGALACIU Research Group

Cyprus International UniversityJanuary 12, 2012


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Agenda

1. Introduction2. Evolution of 802.11p Technology

3. Vehicular communication at a Glance and

Wireless Access in Vehicular Environments(WAVE)4. Modeling Agilents Advanced Design Systems (ADS)

According to IEEE 802.11p for the vehicular environment.

5.

What Well Cover Today!!!

Simulated Results for Fading Channel


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Executive Summary

The Concept

TheOpportunity

Motivation

vehicle-to-vehicle (V2V).

Smart Cars

Safer roads Less traffic Fading


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Introduction

In 2009 the American Federal communicationcommission (FCC) dedicated 75 MHz band widthof 5.850-5.925 GHz for V2V wireless

communication. The vehicular band is locatedright above Unlicensed National InformationInfrastructure (U-NII) radio band. In 2004 a taskgroup under IEEE and OSI committee developed

an initiative that will enhance common Physical(PHY) for Vehicle to Vehicle (V2V) and Vehicle toInfrastructure (V2I) communication at 5.9 GHz.


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Summaries of the IEEE 802.11 Standard

Years Standards Speed Frequency Band

1997 802.11 -97 1Mbps 2 Mbps 2.4 GHz band

1999 802.11a Up to 54 mbps 5 GHz band

1999 802.11b 5.5Mbps 11Mbps 2.4 GHz band

2003 802.11g 54Mbps 108Mbps 2.4 GHz band

2007 802.11n 100 Mbps 2.4 GHz band


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Figure1: WLAN block diagram for IEEE 802.11p scenarios


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In single carrier the information are

represented inform of a bits called

symbol. It has a disadvantage of

transmitting tiny symbol with large

amount of bandwidth making it an

inefficient frequency carrier. symbol are

also venerable to signal reflection,impulse noise and other impairments

In Frequency Division

multiplexing (FDM), the wholedata rate sent is divided betweenthe various subcarriers. However,in this case interference onlyaffects one of the frequency sub-bands, while the others are

unaffected.

Why Orthogonal Frequency division

Multiplexing (OFDM)


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IEEE 802.11p OFDM block diagram


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Physical layer Implementation Comparison of

IEEE 802.11a and IEEE 802.11p.


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WAVE (Wireless Access in VehicularEnvironments)

The standard consists of four sub standards which arestated below

IEEE 1609.1

IEEE 1609.2

IEEE 1609.3

IEEE 1609.4


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DSRC ChannelAllocation


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Vehicular Propagation Channels

Path loss

Signal Fading

Rician Fading DistributionRayleigh Fading Distribution


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Simulation model of IEEE 802.11p base AgilentsAdvanced Design Systems (ADS)


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ADS Transmitter block diagram model


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Transmitter Component

WLAN Data

The PPDU is generated at the WLAN Data; the frame format

consists of 16 bits. The first 6 bits (0 to 6) is set to zero, these bits

are used for synchronizing the descrambler at the receiver. Theremaining bits (7 to 15) reserved for future use. The PPDU tail

bit field comprises of 6 bits of 0, which is used to return the

convolutional encoder to the zero state.

Scrambler


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EncoderScrambled data is transferred to the convolutional encoder byusing linear shift registers. Some redundancy bit stream is

introduced in a controlled way. Its main aim is to correct errors in

coding which enables the receiver to combat the impairments ofthe channel and, hence, achieve reliable communication.

Data interleaving


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Modulation & mapping

PreambleIEEE 802.11p PLCP field is composed of four parts: short preamble,

long preamble, signal and data fields.


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IFFT and FFT

Multiplexing process of OFDM Frames

The logical subcarrier numbers are then mapped into

frequency offset index -26 to 26, while skipping

subcarriers -21, -7, 0, 7 and 21. After that, theassembler block enables the pilot subcarriers to be

inserted into the positions of -21, -7, 7 and 21

Error Vector Magnitude


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Channel Model

Environment & Power Classes 802.11p


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Vehicular Antenna & Properties


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Base Station AntennaIn this research, a base station antennas

of EIA/TIA-329-B, specification is used

Vehicular AntennaA mobile antenna of "EIA/TIA-329-B-1

specification is used in this vehicular

research.


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Receiver Side


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Frequency Domain Equalizer

When receiver realizes a distortion, an equalizer combats the

distortion introduced by the channel.

OFDM symbol de-multiplexer

This section enables the OFDM symbol to be de-multiplexed(e.g. BPSK, QPSK, and 16-QAM modulation) into data andpilot forms. The complex signal is converted to data andpilots .


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Demodulator Bank (De-mapping)

Evaluation of the reliability modules


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Performance on a Typical Urban Fading

Channel


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Above is a simulated result BER against SNR for LOS in a typical urban area BPSK has

a BER of 2.954E-5 at 4.750. QPSK has a low BER of 4.844E-4 at 4.750 and while 16 QAM

has BER of 0.004 at 4.750. From the above result BPSK has the lowest BER against SNR

802 11p BER In A Typical Urban Area For NLOS Fading Channel


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-1 0 1 2 3 4 5 6 7-2 8

1E-5

1E-4

1E-3

1E-2

1E-1

1E-6

6E-1

Eb/No (dB)

BER

802.11p BER In A Typical Urban Area For NLOS Fading Channel

BPSK 3/4

QPSK 3/4

16 QAM 1/2

In the case of NLOS the result indicated that BPSK has a low BER of 1.018E-4 at 4.429.QPSK has a BER of 0.001 at 4.429. And for the 16 QAM it has a low BER of 0.006 at 4.429.

The performance of Figure 13 result is observed to degrade as a result of multipath component and non line of sight between the transmitter and the receiver. Inaddition the result indicates that the environment is associated with a lot building and

Doppler spread that hinder the effective transmission of signal along the channel


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Performance on Free space

802 11p BER In A Free Space For LOS Fading Channel


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-1 0 1 2 3 4 5 6 7 8 9-2 10

1E-5

1E-3

1E-1

1E-7

5E-1

Eb/No(dB)

BER

802.11p BER In A Free Space For LOS Fading Channel

BPSK 3/4

QPSK 3/4

16 QAM 1/2

The figure 5.7 is a representation of LOS result for BER against SNR indicate 0.492 at -2.000

for BPSK and 9.766E-7 at 7.000, the QPSK the result indicate 0.488 at -2.000 for the starting

point and 1.733E-5 at 7.000 for the ending point. And for the 16 QAM it has a starting point of

0.480 at -2.000 with an ending point of 1.074E-5 at 10.000.


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-1 0 1 2 3 4 5 6 7 8 9-2 10

1E-5

1E-4

1E-3

1E-2

1E-1

1E-6

5E-1

Eb/No(dB)

BER

802.11p BER In A Free Space For NLOS Fading Channel

BPSK 3/4QPSK 3/416QAM 1/2

The result above states that BPSK has a BER of 1.416E-5 at 6.250 but it is also

glaring that QPSK and 16 QAM are almost the same indicating that it not a good

choice to use QPSK . However, the result indicates the Figure 5.7 result has the

lowest BER compare to figure 5.8. Due to LOS that exist between the two car

antennas


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THANK YOU !

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