Rf network design

1

Procedure of CDMA RF Engineering

(RF Network Design)

2001. 5.

[email protected]

2

1. Network Design Objective……………….…..3P

2. RF Network Design Procedure……...……..5P

Stage 1: Preparations …...………………………...6P

Stage 2: Wireless Environment Analysis …….21P

Stage 3: Coverage Design ………………………36P

Stage 4: Parameter Design ……………………..50P

Stage 5: Dimensioning …………………………..59P

Contents

Acceptable CoverageForward & Reverse Link Quality

Capacity

To Resolve

To Manage

To Ensure

Engineering Requirement vs. Available EquipmentCustomer Complaints

Pilot Pollution Cell Overlap / Handoff Regions

1. Network Design Objectives

Design Value

Design Criteria

? %

FER

(Frame Error Rate)

? %

GOS

(Blocking Rate)

? %

Coverage

Probability

- Demand for Service Coverage? - Demand for Service Quality? - Demand Service Capacity? - Usable Frequency Bandwidth? - Service Criteria? - Call Completion Rate? - Handoff Success Rate?

Design Objectives

1. Network Design Objectives

5

2. Network Design Procedure

Basic Data Collection & analysisDesign Criteria SetupGIS Data Conversion

Preparations

Competition Coverage MeasurementPlan SetupRegion ClusteringSite Survey Plan

Site AcquisitionSite Coverage Simulation

Link Budget AnalysisBase Station Design On the Map Positioning

Site survey & Field measurementMeasurement data integrationPath loss calculation

RF Environment Analysis

Outdoor/Underground Coverage design In-building and underground

Coverage Design

Pilot AssignmentPaging Capacity & Paging zoneHandoff neighbor list, etc.

Parameter Design

Required BTSRequired FARequired CHC / CE

Dimension & Report

STAGE 1

STAGE 2

STAGE 3

STAGE 4

STAGE 5

6

Target Objective Setup Competitor’s Info. Analysis Sheet Detail Design Criteria - Service Target Area(In Building/In car) - Traffic & Coverage data - FER(Frame Error Rate) - Coverage hole(If possible) - GOS(Grade Of Service) - Coverage reliability

General Statistic Data forDesign Scope- Population and Area- Traffic and BTS info./ GIS MAP- Telecommunication regulation

Competitor’s Service Information - Service Area and Quality (GSM,CDMA) - BTS Info.(Lon/Lat, Traffic & antenna)

Design Objective - GOS/FER/Coverage Reliability - FA capacity - Cell coverage criteria - Soft Handoff region ratio, etc.

General Statistics Data gathering & Analysis - RF Engineering Scope Analysis (Area, Population, Building Density, etc) - Traffic Information(Traffic Distribution analysis) (Traffic volume, call success/completion rate) - BTS Information(Lon/Lat, coverage, etc)

Competition company Traffic Volume and Quality Analysis(If Possible) - BTS and antenna type, position - Traffic analysis per each cell/sector - Overall BTS coverage analysis

Detail DesignCriteria Setup

Required Data/Tool

Main Activity

Accomplishment

Stage 1: Preparations

Overview

7

Setup the Design Criteria

GOS vs. Capacity

0

10

20

30

40

50

60

70

80

90

0.0% 0.1% 0.5% 1.0% 1.5% 2.0% 2.5% 3.0% 3.5% 4.0% 4.5% 5.0% 5.5% 6.0% 6.5% 7.0% 7.5% 8.0% 8.5% 9.0% 9.5% 10.0%

GOS

Erl

an

g

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

Ca

pa

cit

y I

nc

rea

se

Ra

tio

Erlang Capacity Increase Ratio

Traffic Model : Soft Blocking ModelBTS Type : 3 SectorChannel : 84Maximum User : 33Sector Load Ratio : 1.5

GOS(Grade of Service), Blocking Probability


1

1.5

2

2.5

3

3.5

4

1 2 3 4 5 6 7 8 9 10 11 12 13

% FER

Mea

n O

pin

ion

Sco

re

MOS

PSTN = MOS 4 CDMA = 3.6 (FER 1%)

MOS Vs. FER Graph (8K Vocoder)



Setup the Design Criteria Coverage Area and Contour Reliability(FADE MARGIN)

95% Area Reliability 95% Contour Reliability

15% Contour failure

< 10%

< 5%

< 1%

Percent Failure 4-6% Contour failure

< 3%

< 2%

< 1%

Percent Failure

85% contour reliability 97% area reliability


10



0.5

0.6

0.7

0.8

0.9

1

1.1

/n

Fra

cti

on

of

To

tal A

rea

wit

h S

ign

al a

bo

ve

Th

res

ho

ld. F

u

0 1 2 3 4 5 6 7 8

PX0(R) = 0.95

0.9

0.85

0.80.75

0.7

0.65

0.6

0.55

0.5

Area Reliability FuContour Reliability

= Standard deviation[dB]

n = Path slope

Path Loss varies as 1/rn,

PX0(R) = Coverage Probability on area boundary (r = R)

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0

5

10

15

20

25

0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95

Location Probability at Cell Edge

Fad

e M

arg

in in

dB

12 dB

1110

98

7

6

StandardDeviation

Fade Margin -----> 10 dB

Setup the Design Criteria Coverage Area and Contour Reliability(FADE MARGIN)

Item Dense Urban Urban Suburban Rural

Slow Fading 10 dB 8 dB 8 dB 6 dB

Slow Fading It follows the log-normal distribution with standard deviation It depends on a variety of morphology

To obtain the exact slow fading value,must perform the field measurement which consumes the high cost and time


13


FA Capacity(based on IS-95A reverse link) • Limited by Interference From Other users• Based on minimum required [Eb/It]minimum

• Relationship between [Eb/It]minimum and Number of user N based on Perfect Power Control, No Thermal Noise, and Isolated Single Cell

RSNRS

ItEb

/)1(/

1

// ItEbRWN

• S: Received signal at the base station(from power controlled mobiles)• R: Data rate• W: CDMA Bandwidth(1.2288 Mbps)• Eb: Bit energy, It: Spectral Density of the total interference• N: Number of active users


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Pole(Maximum) Capacity(based on IS-95A reverse link)

NoW

IoIocvSNRS

ItEb

N

N

)/1()1(/

)1()1(1 fvNW

R

It

EbWR

ItEb

NoWSN

• Including the effects of Thermal Noise, Voice Activity and other cell interference

Io

Iocf ,where


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Pole(Maximum) Capacity(based on IS-95A reverse link)

• Pole(Max) Capacity, where required

• Obviously, this capacity can never be exceed in any cell/station• Pole(Max) Capacity/Sector

1*1*min)(

max Fv

ItEbRW

N

1)3

55.2(*1*

min)(secmax/ F

vItEbRW

torNf

F

1

1,where


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FA Capacity(based on cdma2000 1x)

)%80%100max

,( )(_ 00

S

k k

kS

kk N

NWhenMbitsMbitsCapacityFA

• Because of difference in required Signal /Noise, Activity and Transmission velocity in each service Nmaxk can be defined follows

)/6.0

1 where,()1

/(max

IoIocFSG

NtEb

FPGN

kk

kk

• Base station FA capacity of service carrying number of S with various transmission velocity



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Cell Coverage • Coverage Criteria in CDMA System - Forward Coverage : Design by the standard of Pilot CH Ec/Io - Reverse Coverage : Design by the standard of Traffic CH Eb/No • As higher Ec/Io and Eb/No criteria are arranged, better call quality can be supplied for customers but more cost is also expected. Therefore, criteria should be arranged to meet the customer satisfaction and cost efficiency

Required Ec/Io

Required Eb/No

Forward Coverage

Reverse Coverage

>= -14dB

>= 6dB



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Soft Handoff Region Ratio

Soft Handoff Region Ratio

0

10

20

30

40

50

60

70

80

-22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11

T_ADD (dB)

Re

gio

n R

ati

o (

%)

2Way Soft Handoff 3Way Soft Handoff Total Soft Handoff

T_ADD is used to add new Active/Candidate set

T_DROP is used to reduce the Active pilot

Because the output power of a mobile station decreases in handoff,

the interference also decreases and the BTS capacity increases.

But required channel resource also increases.

30 ~ 40 %



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PILOT_INC parameter setting

PN offset reuse distance calculation

PN offset allocation - PILOT_INC selection

- Distance between the same PN cell sites

- Extra PN offsets for expansion of cell sites or Micro cells

PN Increment and Allocation



Paging channel Load and Paging zone design Paging channel load calculation

Paging zone design(1st, 2nd Paging zone)

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ХХХ

Tx/Rx-0 Tx/Rx-1

10=3.6m

10=3.6m0.3m(MIN)

Competitor - ANT.

ХХХ

0.3m(MIN)

Competitor-ANT.

Space Diversity Polarization Diversity

Single Site

JointSite

Tx/Rx-0Tx/Rx-1

Tx/Rx-0 Tx/Rx-1

Tx/Rx-0 Tx/Rx-1

Distance between Antennas



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RegionClustering

Maximum Cell Radius,Minimum AntennaHeight Calculation

Site Survey and Field Measurement

Competitor’s CoverageAnalysis

Link BudgetAnalysis

Procedure Overview

Stage 2: RF Environment Analysis

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1. Site Survey Report2. Field Measurement Data and Analysis Result - Measurement Integration & Propagation Modeling3. Frequency Planning4. Competitor’s Coverage Analysis Result

MAP DATA - Digital Map for CellPLAN - 1:10,000 Traffic Map

Cell Planning ToolField Measurement Tool - Transmitter / Receiver - Spectrum Analyzer, etc

Competitor’s CoverageMeasurement Tool - AMPS/CDMA or GSM SystemCompetitor’s Cell Info.etc.

Region clustering - Dense Urban, Urban, Suburban, Rural. - Drive Survey for region clusteringSite Survey & Field Measurement - Make the Site Survey list - Drive Route establishment - Perform the Field Measurement

Spectrum Clearance Check (including Site Survey List)

Frequency Planning Review or Setup - FA Planning

Competitor’s CoverageMeasurement Tool - AMPS/CDMA or GSM System

Required Data/Tool

Main Activity

Accomplishment


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Region Clustering by the Geographical Configuration (Flat, Hilly, Mountain)

General Clustering by the Map Data

(Rural, Suburban, Dense, Urban)

Extraction of the Regional Parameter Values such as BAI(Building

Area Index), BSD(Building Size Distribution), BHD(Building Height

Distribution), VI(Vegetation Index) etc., using the Geometry Function

Applying the Extracted Parameters to the Target Area to Achieve

more Detail Region Clustering

Precisely Divided Region Clustering

Region Clustering


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Region Clustering(Quantitative)

Region Class BAI(%)BSD(m2) BHD(Floors)

VI(%)Avg. STD Avg. STD

Rural Flat, Hilly, Mountain < 12 - - - - -

Suburban

Residential(Open) 12 ~ 20 95 ~ 115 55 ~ 70 2 1 >= 2.5

Residential(no Open) 20 ~ 30 100 ~ 120 70 ~ 90 2 ~ 3 1 <= 5

High-rise residential > = 12 >= 500 >= 90 >= 4 1 <= 2

Urban

Shopping Area 45 ~ 50 200 ~ 250 >= 180 >= 4 1 0

Commercial Area 30 ~ 40 150 ~ 200 >= 160 3 1 0

Industrial Area 35 ~ 45 >= 250 >= 200 2 ~ 3 1 <= 1

Dense

Urban

Shopping Area >= 50 200 ~ 250 >= 180 >= 4 1 0

Commercial Area >= 40 150 ~ 200 >= 160 6 1 0

Industrial Area >= 45 >= 250 >= 200 7 ~ 8 1 <= 1

[Reference] David Parsons “ The mobile radio propagation channel”


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Site Survey and Field Measurement Procedure


Planning

1. Selection of target Building for site survey2. Scheduling for site survey and field measurement3. Planning for Drive route

Site Survey & F.M**

1. Check the test equipment and visit site(building)2. Take a a photograph and fill out the site survey report3. Install the transmitter on the roof of the building4. Install the receiver in a car5. Put the transmitter on6. Start the driving test7. Perform the Site survey & field measurement result analysis - Path loss analysis8. Perform the Competitor’s coverage measurement

Test Equip.* Verification

1. Check the spectrum analyzer self-generated noise level & accuracy2. Setup the Transmitter and check the output power level 3. check the Amplifier Gain by using signal generator and spectrum analyzer4. Measurement of Cable loss - between transmitter and AMP

- between AMP and Antenna

* Equip.: Equipment** F.M: Field Measurement

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Site Survey Planning


Candidate sites shall be selected in each morphology to represent the characteristics of that region and then team organization and scheduling for the site survey and the field measurement shall be made. And the drive route should be decided based on the main road and the road condition

make a plan for site surveying & field measuremnt select a variety of candidate site organize the team for site surveying decide the drive route

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Site Survey Report

4Date :

Site ID :

Visitor :

Bldg . Address :

Bldg . Height : Steel Tower Height : m

Latitude : Longitude :

Special Comment :

Department store,Government office,Competitor site,Hotel, University,Above the10th-story bldg .

Picture No :Avg . Bldg . Height :Major Bldg .:













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Field Measurement - Test Equipment Verification

Checking of the spectrum analyzerSelf-generated Noise level & accuracy

Setting up the Transmitter andChecking Tx Output Power level

by using Spectrum Analyzer

Checking the LPA Gain by using Signal Generator and Spectrum Analyzer

Measurement of Cable Loss a. Between Transmitter and AMP b. Between AMP. and Antenna


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Field Measurement - Drive Test: All road test as possible as can go

FA “A” (Central Channel# A)

FA “B” (Central Channel# B)

Team A

Team B

MS_1 MS_2

MS_3 MS_4

10Km

10Km

Site A

Site BMeasurement Radius


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Field Measurement - Measurement Data Analysis(1)

Perform the Data Gathering and Analysis

Calculate the distance for each measurement point Calculate the average Rx level for unit area (30m * 30m) Calculate the average Rx level for distance

Path Loss Calculation

Path Loss = Transmit signal Power – Received signal power [dBm]

Path Loss data is used to perform the Measurement integration to calculate the exact Propagation model

By using the Cell Planning tool, It will be easy to perform the MI


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Field Measurement - Measurement Data Analysis(2)

PropagationPrediction Model

Measurement Data

Signal Strength

Distance

Propagation Prediction Model

Measurement Data

δ

Signal Strength

Distance

-δ

MEASUREMENT INTEGRATION(MI)


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Competitor’s Coverage Measurement / Analysis

Collecting Information about the Specification of the Competitor’s System

• The site location

• The height of the building and the tower

• Antenna type

• The direction and the angle of the antenna

• Control channel number and the output power by each sector

Measuring the Service Quality• GPS data(altitude & logitude)

• Cell ID (best sever / neighbor cell)

• Rx power (best sever / neighbor cell)

• BCCH (best sever / neighbor cell)


33

Link Budget Analysis

OBJECTIVES OF LBA

To estimate the Maximum Allowable Path Loss for the Reverse Link

To estimate Maximum Allowable Path Loss for the Pilot, Sync, and Paging Channels, including the appropriate path imbalance

To compute the required percentages of Base Station transmit power for the Pilot, Sync, Paging and Traffic Channel

To estimate cell coverage and count


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Link Budget Analysis(Reverse Link)


Reverse LinkMAPL

LBA

Operating Parameters:System % Loading, SHO gain

Subscriber Parameters: Maximum PowerCable lossAntenna GainNoise Figure

Noise FigureBS Parameters:

Antenna GainLosses

Voice Activity & Reuse Factor

Technology Parameters:Bandwidth, Data Rate ( Proc. Gain)Required Eb/It

Propagation Parameters:Fade Margin, Penetration Loss

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Link Budget Table(Example: SKTelecom)

Uni t Val ue RemarkFrequency MHz 877 CustomerBandwi dth MHz 1. 2288 Spec.Data Rate bps 9600 CustomerProcessi ng Gai n dB 21 Cal cul ated%Loadi ng % 50%CustomerRequi red Area Rel i abi l i ty % 95%Customer

Morhpol ogy Cl ass D. Urban Urban S. Urban Rural Open Remark

At Mobi l e Stati on (TX)Mobi l e Tx Power dBm 23. 0 23. 0 23. 0 23. 0 23. 0 Spec. (Cl assI I I )Antenna Gai n dBi 0. 0 0. 0 0. 0 0. 0 0. 0 CustomerBody Loss dB 3. 0 3. 0 3. 0 3. 0 3. 0 Customer

At Base Stati on (RX)Noi se Densi ty(KT) dBm/ Hz -174. 0 -174. 0 -174. 0 -174. 0 -174. 0 Spec.Noi se Fi gure(F) dB 5. 0 5. 0 5. 0 5. 0 5. 0 Vendor Spec.Noi se Bandwi dth dB 60. 9 60. 9 60. 9 60. 9 60. 9 Spec.Noi se(KTBF) dBm -108. 1 -108. 1 -108. 1 -108. 1 -108. 1 Cal cul atedRequi red Eb/ Nt dB 6. 0 6. 0 6. 0 6. 0 7. 0 Vendor Spec. f or 1% FERLoadi ng Correct i on (1-x) dB 0. 0 0. 0 0. 0 0. 0 0. 0Sensi t i vi ty dBm -123. 2 -123. 2 -123. 2 -123. 2 -122. 2 Cal cul atedRecei ve Antenna Gai n dBi 18. 0 18. 0 14. 1 14. 1 14. 1 CustomerCabl e & Di pl exer Loss dB 3. 0 3. 0 3. 0 3. 0 3. 0 CustomerSHO Gai n dB 3. 0 3. 0 3. 0 3. 0 3. 0 Customer

At Radi o ChannelSl ow Fadi ng dB 10. 0 8. 0 8. 0 6. 0 3. 0 CustomerAtten. Factor of Propagati on dB/ dec 3. 5 3. 5 3. 5 3. 5 3. 5 Cal cul atedS. F/ A. F 2. 9 2. 3 2. 3 1. 7 0. 9 Cal cul atedFade Margi n dB 11. 0 8. 5 8. 5 6. 0 3. 5 Cal cul ated

At Servi ce Condi ti onRequi red Contour Rel i abi l i ty % 87. 0 86. 0 86. 0 83. 0 75. 0 Cal cul atedPenetrat i on Loss ( i n car) dB 5. 0 5. 0 5. 0 5. 0 5. 0 CustomerPenetrat i on Loss ( i n bui l di ng) dB 18. 0 15. 0 10. 0 10. 0 10. 0 Customer

OutputMax. Al l ow. PL (on street) dB 150. 2 152. 7 148. 8 151. 3 152. 8 Cal cul atedMax. Al l ow. PL ( i n car) dB 145. 2 147. 7 143. 8 146. 3 147. 8 Cal cul atedMax. Al l ow. PL ( i n bui l di ng) dB 132. 2 137. 7 138. 8 141. 3 142. 8 Cal cul atedMS Antenna Hei ght 1. 5 1. 5 1. 5 1. 5 1. 5BS Antenna Hegi ht 21. 0 25. 0 30. 0 45. 0 45. 0Max. Al l ow. Di stance(on street) km 6. 2 8. 0 6. 9 10. 2 11. 3 Cal cul atedMax. Al l ow. Di stance(i n car) km 4. 5 5. 8 4. 9 7. 3 8. 1 Cal cul atedMax. Al l ow. Di stance(i n bui l di ng) km 1. 97 3. 0 3. 6 5. 2 5. 8 Cal cul ated


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• Outputs - Sites location - Antenna type - Antenna tower height - Antenna orientation / tilt - O/H Output power

- Candidate site location- Site acquisition report

- Coverage Plot- Recommendation on next candidate sites

• Considering Factors - Maximum cell radius - Traffic distribution - Competitor’s coverage

Designing onthe Map

Finding-out Sites Location and

Initial Parameter Value

Site Acquisition

CoverageSimulation

Coverage Design Procedure

Stage 3: Coverage Design Ⅰ

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Design on the Map result CellPLAN simulation Plot Equp. Type Decision(Initial)

- Anchor site position result - Initial coverage design map - Initial Capacity analysis

- Cell site Position(Morphology) FWD Ec/Io, REV Eb/Nt Plot - Traffic estimation per cell site

H/O region analysis plot

Mobile ERP Plot


CellPLAN Tool - SKTelecom Design Tool - Initial coverage simulation)Map Info S/W - Design on the Map(Note PC based)

LBA Result - Maximum cell radius - Minimum antenna height - Minimum cell site no

Design on the Map with MAP INFO Tool

- Anchor site selection

(In Dense Urban area, high traffic density)

- Site positioning through the anchor site

CellPLAN Coverage Simulation

- Initial Coverage design by using

CellPLAN Tool(FWD/REV Coverage)

- Initial Capacity analysis based on

the traffic prediction

Equip. Type Decision(Initial)

- BTS, Small BTS, pico BTS

- Fiber optic Micro cell

- RF Repeater

Required Data/Tool

Main Activity

Accomplishment


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Design on the MAP


Coverage design consists of designing on the map, site acquisition and coverage simulation. Especially, site acquisition and coverage simulation is verified and modified repeatedly to achieve optimal coverage design(Iterative)

Cell site location is decided on the map by means of using the maximum cell radius, competitor’s site location and the result of the coverage analysis with consideration of estimated traffic in future

Initial Coverage Simulation After designing on the map, it must qualify the cell site location through the coverage simulation by using RF planning Tool(In case of SKTelecom, there is a cell planning tool named CellPLAN) - Forward / Reverse Coverage simulation - Soft handoff region, etc

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Existing Network Traffic Analysis Procedure

PEG Data Collection and Validity Check

Site/Sector’s Representative Carried Traffic and

Blocking Rate Calculation

• PEG count data collection for 2 Weeks • Abnormal data deletion (Beyond the limit of Avg Traffic 50%) - Too small traffic by an obstacle of BTS - Excessive traffic by PEG counting errors

• Representative Carried Traffic = Avg Carried Traffic + 1.28 * Std (Range of 90% reliability)

• Blocking rate calculating for each sector and site

• Offered Traffic = Carried Traffic * (1+Blocking Rate) Site/Sector’s Offered

Traffic Calculation

Traffic Distribution Analysis


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• Divide total area into unit area(Aij)• Decide weighting factor each unit area (Wij)

• Wij = 1

Traffic Distribution

1

2

3

j

n

1 2 3 i m

Wij

W11 W12 W13

W21 W22 W23

W32 W33W31

Wnm

Traffic Weighting Map(Mobile Telecom Introduction Stage)

- Traffic Volume - Population Density - Land Usage Shape - Resident Living Standard



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• Divide total area into unit area(Aij)• Calculate occurred traffic each BTS/Sector • Distribute traffic uniformly within BTS/Sector coverage • Decide weighting factor each unit area (Wij) ( Wij = 1)• Distribute the traffic of target year to unit area with weighting factor

Coverage Design and Dimensioning

1

2

3

j

n

1 2 3 i m

WijSite B Site D

W11 W12 W13

W21 W22 W23

W32 W33W31

Wnm

Site C

Traffic Weighting Map(Competitor In Service) • Additional Factor to be

Considered• BTS / Sector Traffic



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Site Acquisition result CellPLAN simulation Result Plot Antenna azimuth & Tilt Degree

- Detail Cell site position - Forward Coverage Plot

- No. of Site Acquisition - Reverse Coverage Plot Initial Overhead Power setup

- Cell site type Decision (Including FMC & RF Repeater)

(BTS, FMC, RF Repeater)


CellPLAN Tool - SKTelecom Design Tool - Detail coverage simulation (Iterative coverage Simulation)

Result of Design on the MAP - Anchor site position result - each site position, etc

Site Acquisition & Simulation(Iterative) - Search area ring setup for each cell site (SAR: one of fourth area per cell radius) - Making the candidate site list survey - Visit the candidate site

Site Acquisition & Simulation(Iterative) - Check the cell site qualification (LOS, Building Rent or room, etc) - Antenna azimuth & tilt degree decision

CellPLAN Simulation (Iterative & Detail)

- Forward Ec/Io plo

- Reverse Eb/Nt plot

- H/O Region analysis plot

- Mobile ERP plot, etc

Required Data/Tool

Main Activity

Accomplishment

Stage 3: Coverage Design Ⅱ

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Site Acquisition Site Acquisition Procedure

Pre-visit Analysis and Rank Candidate Sites

All SitesUnacceptable

Visit Sites

Perform and EvaluateDrive Test

Notify Real Estate

Visit Search Area

Revise Objectives

Redesign System

Release SAMs for Site Search

YES

NO


44

Site Acquisition


Pre-visit analysis and rank the candidate sites The first of the site acquisition is to identify multiple candidates for each site location, evaluate them on various criteria and rank them accordingly. This procedure results in identification of the best suited candidates for all sites. If all the candidates for any site are rejected for any reason(s), alternatives have to be found, or the objectives revised and candidates reevaluated, and,if all else fails, redesign the system/partial system.

The ranking of the candidate is done in two steps - A preliminary ranking and visit to the top three candidates,followed by the final ranking. Approval is then given to up to three Candidates and the first site that passes the drive test, if required, is accepted.

45

Site Acquisition


Select the Anchor Sites(initial design stage) Anchor sites dictates the overall RF network design. They determine the rest of the search rings. Generate an initial cell site layout, starting with anchor cells and using the preferred/desired locations and the pre-qualified site candidates.

Setup the Search Area Ring Search rings define the areas where a need for antenna placement has been determined. Search rings are not precise cell site locations.

Prepare a list of candidates to visit Since it is not possible, nor necessary, to visit all the candidate sites, the top two or three candidates from the first part of the ranking matrix are to be visited. Since a site cannot be acquired unti11 it is visited, it is in the interest of speedy acquisition that the best potential candidates be visited

46

Site Acquisition


Site Visit Activities CHECK LOCATION DATA, using the maps or GPS. And record it CHECK OBSTRUCTIONS in all directions, e.g. tall building, unobstructed line of sight for microwave propagation, airports, other antennas, AM stations, etc. ORIENT THE ANTENNA using a compass. Getting an orientation degree is important to evaluate the coverage effectiveness of this site TAKE MEASUREMENT of distance between equipment shelter and antennas (cable run), dimensions of the equipment shelter and compared to the dimensions of the vendor equipment. TAKE PICTURES to document intervening structures/unusual topography of the site.

47

Site Acquisition


Redesign of the system In the event that all sites initially recommended by Real Estate are unacceptable, reevaluation of rejected sites is not feasible and no alternatives can be identified, the recourse is to revise objectives and redesign the system if needed. This process is initiated by forwarding the Redesign Request to RF Engineering, identifying the reason(s) why this situation arose, and, upfront, making some suggestions or issues to bear in mind while redesigning the system. This facilitates a successful redesign, with less chances of again yielding unacceptable candidates.

48

Coverage Simulation

• Measurement Integration• Forward Link Analysis - RSSI - Pilot Ec/Io - Soft Handoff•Reverse Link Analysis - Mobile ERP - Traffic Eb/Nt

• GIS DB - Terrain - Morphology - Vector - Building

• Propagation Prediction Model • Field Measurement Data• Cell Site Parameters • Traffic Distribution

CDMA Cellular Wireless Network

Analysis

Personal ComputerWindow 95

CellPLAN

CellPLAN Structure


49


Coverage Simulation Main Activities

Forward Coverage Analysis Forward Pilot Ec/Io Plot Forward Pilot Best Server plot Forward Pilot Eb/Nt plot Reverse Coverage Analysis Reverse Traffic Eb/Nt plot Reverse Mobile ERP Plot Soft Handoff region ratio and Analysis CDMA Forward/Reverse Link Coverage Analysis 2D/3D profile for LOS check, etc

50

PN Offset Allocation Result Paging zone Decision H/O Neighbor list simulation - PILOT_INC Decision - Paging channel capacity calc. - make the H/O neighbor list - PN Offset Reuse Distance Calculation - Paging zone decision - Cell site PN Offset Allocation BTS O/H Power Simulation

Design Criteria - PILOT Assignment - Soft Handoff Region ratio - Paging channel capacity - Paging zone

Cell Plan Tool - Handoff simulation - coverage simulation, etc

PN Offset Allocation - PILOT_INC Calculation (Lower/Upper Limit) - PN Offset Reuse Distance Calculation - Base Station PN Offset Allocation

Paging Zone Decision - Paging Channel Capacity Calc. - Paging Zone Decision

Handoff Neighbor List Simulation - Handoff neighbor list

BTS Overhead Power Simulation

Required Data/Tool

Main Activity

Accomplishment

Stage 4: Parameter Design

51

- PN offset allocation

- Paging zone

- Handoff neighbor list

- Overhead power

• Use coverage design result and design criteria• Design results are used the initial operation value of system

parameters• Adjust the system parameters according to optimization after

system in-service• Designed parameters

Parameter Design


52

Parameter Design (Pilot offset allocation)


Lower Limit for PILOT_INC

No interference Condition between δ1 and δ2

1. To prevent the presence of a pilot signal with

a different PN offset in the active search window

due to a large differential delay

2. To prevent the presence of a pilot signal with

an undesired PN offset in the neighbor search

window due to a large differential delay

ri : Cell radiusδi : Pilot PN Phase offsetτi : Time delay between Cell site and Mobile stationSA : active search window size (one sided)SN : neighbor search window size(one sided)

PILOT Interference between sites

p1

p2

Interference

p

r1 chips

r2 chips

PN Offset = δ2 chips

PN Offset = δ1 chips

53

δ1 δ2

α1+τ1 δ2 +τ2

sA

Cell Tx PN timing

Mobile Rx PN timing

Active SearchWindowEarliest arriving

multipath of a pilot

Condition 1

(δ2 + τ2) - (δ1 + τ1) >SA

δ12 = δ2 - δ1 > SA + max{τ1 - τ2} max{τ1 - τ2} = r1

δ1+τ0 δ2 +τ0

sN

Mobile Rx PN timing

Earliest arriving multipath of a pilot

Condition 2

δ0+τ0 δ1+τ1δ2 +τ2

sA

sN

Neighbor SearchWindow

δ2 + τ0 - SN > δ1 + τ0 + SN

δ12 = δ2 - δ1 > 2SN

δ12 = δ2 - δ1 > max{SA + r1, 2SN}

δ12 = PILOT_INC * 64 PILOT_INC * 64 > 2 SN

(SN > SA ,SN > r1)

sN sN



54

Pilot PN Offset Reuse

Pi : cell site Tx Powerdi : Distance between Cell site and MSi : Pathloss exponentdi : Distance between cell sitesT : Threshold value



PILOT PN OFFSET REUSE

Cell 3

r3 chips

Cell 1

r1 chips

Phase Offset = δ1 chips Phase Offset = δ1 chips

Cell 2

r2 chips

D chips

Phase Offset = δ2 chips

No interference Condition between δ1 and δ2

1. To prevent undesired finger output for the pilot

signal from distant reuse cell

2. To guarantee the absence of the undesired finger

output for the pilot signal from distant reuse cell

3. To prevent indistinguish ability of sectors with the

same offset in other’s neighbor search window

55

Condition 1

D > 6.8r

Condition 2

If d1=r1, d3=D-r1 (Worst case)

edd

PP b

T

)(

1

3

3

1 31

β

1

)(

3

11

311

ePPr

bTD

β

τ3 - τ1 >SA

If τ1=r1, τ3=D-r1

D > 2r + SA

Condition 3

To distinguish the cell1, cell 3 at the cell 2, must keep the distance above 2r2 + s2N

In case of straight line of three cell sites(worst case)

D > 2(2r2 + s2N)

Equal size sells & Power

= 3.84, T = 19dB

8dB stdev for the shadow fading

D > MAX(condition1, condition2, condition3)

> MAX(condition1, condition3)

Reuse Distance



56

Parameter Design (Paging channel analysis)


General AssumptionNumerical

ValueGeneral Assumption

Numerical Value

a. Paging Channel Capacity 9600 bps j. System Parameter Message 264 bits

b. Maximum allowable utilization 0.9(90%) k. Access Parameter Message 184 bits

c. Paging Strategy(No. of users) 2 l. Neighbor List Message 216 bits

d. Termination Rate 0.35 m. CDMA Channel List Message 88 bits

e. Busy Rate 0.03 n. Extended System Parameter Message 112 bits

f. BHCA per Subscriber 2 o. Channel Assignment Message 144 bits

g. Number of Sectors per MSC ----- p. Order Message

h. General Page 136 bitsVoice Mail Service

q. Voice Mail Notification 720 bits

i. Overhead Message I=j+k+l+m+nShort Message Servicer. Data Burst Message(x: No. of character) 7x+380 bits

s._DONE Message 72 bits

Assumption & Paging channel MSG Lengths

57

Parameter Design (Paging channel analysis)

1 Pagi ng Capaci ty Anal ysi s Tabl e 2 Si ze3 Number Of Users 200000 Subscri bers4 Number of power Up/ Down per day 55 Ti mer based Regi strat i on peri od parameter 64 Ti me Based Regi strat i on Peri od

6 TI mer based Regi strat i on peri od val ue - Second 5242. 88 I F(POWER(2, (C5/ 4))*0. 08= 0. 08, 0, POWER(2, (C5/ 4))*0. 08) :Typi cal Val ue of Reg. Peri od

7 Another Regi strat i on 0 Zone-based Reg. Etc89 Number of Zones 1 1 zo ne As su m p ti o n10 Number of BTS per Zone 24. 0011 Number of Sectors per BTS 312 Number of BTS i n System 2413 Sectors i n System 72 C11*C1214 Regi strati on

15 Total Regi strat i on i n the System per Day 5295898 C3*(C4*2+3600*24/ C6+C7) : Power On/ Off , Ti me Based, Zonebased r e g .e t c

16 Concentrati on rate of BHCA 0. 098


58

Parameter Design (H/O neighbor list)


• make the H/O neighbor list by using CellPLAN tool. (Maximum List: 20 EA / Cell Site)

• 1st, 2nd Cluster analysis(1,2 tier analysis)• Search Window Size decision - Active Search Window Size

- Neighbor Search Window Size

- Remaining Search Window Size

59

Yearly based Dimensioning result

- Required BTS no. - Required FA no.

- Required CHC no.

- Required channel element no.)

Marketing Demand Analysis- Subscriber forecasting- MOU(Minute of Usage)- Traffic prediction

Equipment Type - capacity per equipment - coverage per equipment

Cell site trafficDistribution analysis

Engineering sheet Drawing Up - FA growth calculation - Channel Card quantity - Channel element quantity

Engineering sheet Drawing Up for yearly based dimensioning - No. of Required FA - No. of Required Channel Element - No. of Required CHC(Channel Card)

Required Data/Tool

Main Activity

Accomplishment

Stage 5: Dimensioning

60

Dimensioning Procedure

Design Criteria - MAX. CE per FA - MIN. CC - GOS(Blocking Rate)

Estimated Traffic - Carried Traffic - Soft Handoff Traffic

Cell Site Configuration - Channel Card Type - BTS Type

FA DimensionBTS Dimensioning

Loading Calculation

Module

Required CE CalculateRequired CECalculation

Module

Required CC Calculate CE per CC


61

Predicted Traffic Calculation by Subscriber’s MOU Analysis

• Total Traffic and Traffic per Sub. Calculation

- Erlang / Sub. = MOU per Sub. / ACDM * BHDR / MH

- Total Erlang = Erlang / Sub. * Total Estimated Sub.

BHDR : Busy Hour Day Ratio

ACDM : Average Calling Days per Month(Use 26 or 27 days)

MH : Minutes per Hours(60 Minute)

• The Required BTS by the year• The Required FA No.• The Required CE and CHC calculation

Engineering Sheet Drawing up
