06-WiMAX Coverage Planning and Capacity Calculation-36-OK

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WiMAX Coverage Planning and Capacity

Calculation

ZTE University

CDMA-BSS Team



Objective

After course training, you will:

Master link budget principle

Calculate BS coverage range Know how to calculate capacity



Contents

Radio Propagation Characteristics

Link Budget Principle and Meaning

How to Calculate BS Coverage RangeCoverage Influence Factors

Capacity Calculation Method



Three Basic Propagation Methods

Reflection

f Radio waves encounter with a stumbling block whose

surface is much longer than the wave length.

Diffraction

f Radio waves encounter with an acute angle or slim bar.

Scattering

f Radio waves encounter with large quantities of grains

whose size is much shorter than the wave length.



Slow Fading and Quick Fading

Slow fading represents a slow change of receiver mean

value varying with propagation distance and

environments in a period of time.

Quick fading represents a quick fluctuation of received

signals in a short period of time.



Multipath Fading

Multipath FadingWhen a receiver moves in a complex environment where reflection or

diffraction may occur, a level change of several tens of decibels and violent

phase swinging will take place in a range less than one wave length.



Radio Signals in Land Mobile Communication

The propagation path of radio signals sent by BS

depends on terrain and ground objects. The higher BS is

located, the farther signals are transmitted.

Multipath propagation such as reflection, diffraction and

scattering greatly affects propagation of radio waves, and

sometimes leads to serious signal fading.

Higher frequency of radio waves results in more

propagation path loss, lower diffraction capability and

shorter propagation distance.



Wave Propagation in Ur ban

Fewer radio waves can directly reach to MS. In most of cases,

signals received by MS are superimpositions of reflected waves,

diffracted waves and scattered waves.



MHZ Km fs f d dB L 10log20log2045.32)(10

!

Free Space Propagation Path Loss:

The longer the propagation

distance, the greater the path

loss.The higher the wave frequency, the

greater the path loss.

Free Space Propagation Path Loss



PropagationM

odel:PL(dB)=Function(F, HA, HM, D, C)

PL: Path lossF: Frequency (Unit: MHz)

D: Distance (Unit: km)H: BS antenna/MS effective height (Unit: m)C: Environment correction factor, including denseurban, urban, suburb and rural

Path Loss

Fading margin (dB)Penetration loss (dB)

Receiver (dBm)Transmitter (dBm) Allowed path loss

--

-=



Input itemsFrequency

Distance

Antenna effectiveheight

Terrain (ur ban, subur b,

rural)

RSSI,

dBm

-120

-110

-100

-90

-80

-70

-60

-50

0 3 6 9 12 15 18 21 24 27 30 33

Distance from Cell Site, km

Field

Strength,

dBuV/m

+90

+80

+70

+60

+50

+40

+30

+20

Blue line: Drivetest result

Gray line: Hatamodel expectedresult

Hata Model

PL (dB) = 69.55 + 26.16 log (F) - 13.82 log(H) + (44. 9 - 6.55 log(H) )*log (D) + CHata Model

PL (dB) = 69.55 + 26.16 log (F) - 13.82 log(H) + (44. 9 - 6.55 log(H) )*log (D) + C

Hata Model

PL: Path lossF: Frequency (Unit: MHz) (150 - 1500

MHz)D: Distance (Unit: km)

H: BS antenna effective height (Unit: m)C: Environment correction factor.

Value range: Dense Urban: 0 dBUrban: - 5 dBSuburb: - 10 dBRural: - 17 dB

Hata Model

PL: Path lossF: Frequency (Unit: MHz) (150 - 1500


H: BS antenna effective height (Unit: m)C: Environment correction factor.

Value range: Dense Urban: 0 dBUrban: - 5 dBSuburb: - 10 dBRural: - 17 dB

COST-231

PL (dB) = 46.3 + 33.9*logF - 13.82*logH + (44.9 - 6.55*logH)*log D + C

COST-231

PL (dB) = 46.3 + 33.9*logF - 13.82*logH + (44.9 - 6.55*logH)*log D + C

COST-231

PL: Path loss

F: Frequency (Unit: MHz) (1500 - 2000


H: BS antenna effective height (Unit: m)

C: Environment correction factor.

Value range: Dense Urban: -2 dB

Urban: -5 dBSuburb: -8 dBRural: -10 dBChampaign: -26 dB

COST-231

PL: Path loss

F: Frequency (Unit: MHz) (1500 - 2000


H: BS antenna effective height (Unit: m)

C: Environment correction factor.

Value range: Dense Urban: -2 dB

Urban: -5 dBSuburb: -8 dBRural: -10 dBChampaign: -26 dB

Hate Model and COST-231 Model



Contents



How to Calculate BS CoverageR

angeCoverage Influence Factors




Receiver

Antenna

Antenna

Transmission line

Transmitter

Transmission line

Power output

Transmissionline loss

Gain

Path loss

Gain

Transmissionline loss

Sensitivity

Margin

Radio Link Components



Uplink

Downlink

MS BSFeeder

loss

Antenna

gainPath loss

Antenna

gain

Feeder

lossMargin

Link budget

Determines allowed

maximum path loss.

Determines the maximum

cell radius.

Downlink/uplink

K eeps balanced.

Building

Margin: Fading + Penetration Loss +...

Link Budget Model



Transmitter

Cable or body loss (dB)

Transmitter antenna gain (dBi)

Transmitter power (dBm)Transmitter EIRP (dBm)

-

+

=



Main mechanism:

Diffraction,

refraction

Calculation method:

Statistics

Building penetrationCar penetration

?

?

?

Typical building penetration loss values

Dense urban area

Urban

Suburb

Rural

25 dB

20 dB

15 dB

6 dB

Champaign 0 dB

Penetration Loss



90%

75%

Assume that MS can reliably receive -105dBm levelin at least 75% of cell edge area (90% of cell area)

and the standard deviation is 8dB.

As shown in the right figure, the probability

corresponding to 0.675is 0.75%.

0.675 x 8 = 5.4 dB

-105 + 5.4 = -99.6 dBm

The median level strength should be set to -99.6

dBm.

Cumulated normal probability distribution

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%100%

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3

75%

0.675 W

Area

-99.6dBm

W!dB

Probability density

Rx

Normal distribution0.675 W!d&

- 105 dBm

Fading Margin



Body Loss

At present the body loss for link budget

is 3dB.

It is omitted for data service.

Link Budget Description (I)



Building Penetration Loss

Here gives experience values:

Dense Ur ban: 25dB

Ur ban: 20dB

Subur b: 15dB

Rural: 6dB

The actual penetration loss depends on the actual situation.

Interference Margin

Link Budget Description (VIII)

Loading

!1

1Interference margin



Antenna Height

The antenna should stand low in dense ur ban with

centralized capacity distribution to reduce pilot pollution

and interference on other areas.

The antenna should stand high in champaign with

decentralized capacity distribution to provide large

coverage.

Antenna height:

Dense ur ban: 30 m

Ur ban: 40 m

Subur b and rural: 50 m

Link Budget Description (IX)



Contents








WiM AX Link Budget DL Traffic UL Traffic DLM AP

Item Unit Value Value Value

ApplicationScenario - Mobility Mobility Mobility

Coverage Level - indoor indoor indoor

Frequency MHz 2500 2500 2500

Max. Data Rate at Coverage Edgekbp

s 984 64.00 -

FFT Size - 1024 1024 1024

Permutation - PUSC Total PUSC Total PUSC Total

TDD Channel Bandwidth MHz 10 10 10

FrequencyReuse - 2*6*3 2*6*3 2*6*3

Modulation Mode at Coverage Edge - QPSK QPSK QPSK

Coding Mode at Coverage Edge CTC 1/2 CTC 1/2 CTC 1/8

System Configuration - 2*4MIMO - 2*4MIMO

Num. of TransmittingSymbol - 28 12 2

RepetitionTime - 1.00 1.00 -

Num. of Subchannel to Meet Data

Rate- - 2.00 -

HARQ Time - 4.00 1.00 -

Dense Ur ban Link Budget



Dense Ur ban

Link Budget

Table

0.430.270.57kmRadius of RF Coverage

ZTE General for 2.5GHzZTE General for 2.5GHzZTE General for 2.5GHz-Propagation Model

1.501.501.50mSS Antenna Height

303030mBS Antenna Height

CoverageDistance Cal.

127.78120.20132.77dBLink Budget

181818dBPenetration Margin

2.003.002.00dBInterference Margin

7.39 7.39 7.39 dBShadow Margin for 90% Area Rate

System Margin

---dB4*4BF Gain for DL Traffic

0.006.02dBHARQ Gain

-0.000.00dBRepetition Gain

-12.43-dBSubchannel Gain

System Gain

-101.29 -113.16 -96.62dB

mRx Sensitivity

0.0017.500.00dBiRx Antenna Gain

-3.311.700.74 dBRequired SINR at Antenna Port

0.003.000.00dBRx Filter Loss + Cable Loss

74 7dBRx Noise Figure

24 2-Num. of Rx Antenna

Receiver Side

53.8823.0057.51dB

mTx EIRP

3.000.003.00dBRF Filter + Cable Loss

17.500.0017.50dBiTx Antenna Gain

0.00.03.0dBMultiple Antenna Combining Gain

402340dB

mTx Power per Antenna

112-Num. of Tx Antenna

Transmiter Side

ValueValueValueUnitItem

DL M APUL TrafficDL TrafficWiM AX Link Budget

0.430.270.57kmRadius of RF Coverage

ZTE General for 2.5GHzZTE General for 2.5GHzZTE General for 2.5GHz-Propagation Model

1.501.501.50mSS Antenna Height

303030mBS Antenna Height

CoverageDistance Cal.

127.78120.20132.77dBLink Budget

181818dBPenetration Margin

2.003.002.00dBInterference Margin

7.39 7.39 7.39 dBShadow Margin for 90% Area Rate

System Margin

---dB4*4BF Gain for DL Traffic

0.006.02dBHARQ Gain

-0.000.00dBRepetition Gain

-12.43-dBSubchannel Gain

System Gain

-101.29 -113.16 -96.62dB

mRx Sensitivity

0.0017.500.00dBiRx Antenna Gain

-3.311.700.74 dBRequired SINR at Antenna Port

0.003.000.00dBRx Filter Loss + Cable Loss

74 7dBRx Noise Figure

24 2-Num. of Rx Antenna

Receiver Side

53.8823.0057.51dB

mTx EIRP

3.000.003.00dBRF Filter + Cable Loss

17.500.0017.50dBiTx Antenna Gain

0.00.03.0dBMultiple Antenna Combining Gain

402340dB

mTx Power per Antenna

112-Num. of Tx Antenna

Transmiter Side

ValueValueValueUnitItem

DL M APUL TrafficDL TrafficWiM AX Link Budget



InWiM AX networks, the coverage of every BS

varies with antenna height, antenna type (gain,

horizontal beamwidth and vertical beamwidth),

downtilt and transmit power. To accuratelyestimate coverage of a BS, the propagation

forecasting model should fully consider these

parameters.

Link Budget Description



Link Budget Description

The link budget uses the propagation model ZTE General

for 2.5GHz and is applicable for 2.5GHz signal

propagation.



Coverage Planning

Investigate and classify large coverage into, for example, urban,

suburb, or rural, and understand terrain and building distribution of the

area.

Make link budget.

f Know the edge coverage rate of the area and choose a proper log normalfading variance according to the terrain and a proper building penetration

loss according to the building distribution. Make link budget by using a

proper propagation model to obtain the maximum coverage radius.

Estimate the number of carrier sectors that can meet the coverage

requirement.

f Estimate the number of required BSs according to sector coverage and

area dimension.

(The planning considers coverage area only

regardless of capacity.)



Contents








Coverage Influence Factor I

Improper BS position

Improper antenna height

Improper BS model

Improper azimuth planning



Coverage Influence Factor II

Engineering Installation Problems

f Too long feeder leads to great feeder loss.

f Unqualified feeder connector leads to great insertion loss.

fWatered antenna or feeder leads to great loss.

f The antenna installation does not meet the height, azimuth

or downtilt requirement.

f Standing wave ratio alarm.



Coverage Influence Factor III

Inaccurate engineering parameters



Contents








Capacity (Throughput) Calculation

Concept of Slot

f For any uplink or downlink subframe, the corresponding slot contains 48data tones. This indicates every slot can carry 48 modulation and codingsymbols.

f Take 10MHz systems as an example:

f The frame length is 5 ms. Assume that the downlink subframe is allocated

with 31 symbols and the uplink subframe with 15 symbols.

f In the downlink subframe, the overhead is assigned with 3 symbols amongwhich one is for the preamble and the other two for FCH and DLM APrespectively.

f In the uplink subframe, the overhead is assigned with 3 symbols for ranging.

The number of slots in the downlink subframe: 30*(31-3)/2=420. The number of slots in the uplink subframe: 35*(15-3)/3=140

f The downlink subframe should bear UL M AP. Assume that UL M APoccupies 30 slots (30 subchannels, 2 symbols).

f The DCD/UCD transmission period is 400*5ms=2s. The number of slotsoccupied by the DCD/UCD overhead per frame is 90/400 and can beomitted.



Downlink Subframe PHY Traffic Calculation

QPSK 1/2: DL Throughput= (420-30)*48*200=3.744Mbps

QPSK 3/4: DL Throughput= (420-30)*48*200*3/2=5.616Mbps

16QAM 1/2: DL Throughput= (420-30)*48*200*2=7.488Mbps




64QAM 3/4: DL Throughput= (420-30)*48*200*4.5=16.848Mbps


In 2×2MIMO (SM) mode, these traffics are doubled.



Uplink Subframe PHY Traffic Calculation

QPSK 1/2: UL Throughput=140*48*200= 1.344Mbps

QPSK 3/4: : UL Throughput=140*48*200*3/2= 2.016Mbps

16QAM 1/2: UL Throughput=140*48*200*2= 2.688Mbps

16QAM 3/4: UL Throughput=140*48*200*3= 4.032Mbps

In 2×2MIMO (SM) mode, these traffics are doubled.



Summary

Which factors are related with radio

propagation air loss?

Which factors affect BS coverage?

How to calculate throughput?

SummarySummary



Documents

06-WiMAX Coverage Planning and Capacity Calculation-36-OK