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RF Network Planning

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What is Optimization ?

Design

PlanningOptimization

Implementation

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Introduction

The high level life cycle of the RF network planning process can besummarised as follows :-

To help the operatorto identify their RFdesign requirement

Optional

Discuss and agree RFdesign parameters,assumptions andobjectives with thecustomer

Coverage requirement

Traffic requirement Various level of design(ROM to detail RFdesign)

Issuing of search ring Cand. assessment Site survey, design,approval

Drive test (optional)

Frequency plan Neighbour list RF OMC data Optimisation

ComparativeAnalysis

RF Designrequirement

RF Design

SiteRealisation

RF DesignImplementation

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Comparative Analysis

This is an optional step

This is intended to :-

Help an existing operator in building/expanding their network

Help a new operator in identifying their RF network requirement, e.g.where their network should be built

For the comparative analysis, we would need to :-

Identify all network that are competitors to the customer

Design drive routes that take in the high density traffic areas of interest

Include areas where the customer has no or poor service and thecompetitors have service

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Comparative Analysis

The result of the analysis should include :-

For an existing operator

All problems encountered in the customers network

All areas where the customer has no service and a competitor does

Recommendations for solving any coverage and quality problems

For a new operator

Strengths and weaknesses in the competitors network

Problem encountered in the competitors network

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RF Network Design Inputs

The RF design inputs can be divided into :-

Coverage requirements

Target coverage areas

Service types for the target coverage areas. These should be markedgeographically

Coverage area probability

Penetration Loss of buildings and in-cars

Capacity requirements

Erlang per subscriber during the busy hour

Quality of service for the air interface, in terms GoS

Network capacity

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RF Network Design Inputs

Available spectrum and frequency usage restriction, if any

List of available, existing and/or friendly sites that should be included inthe RF design

Limitation of the quantity of sites and radios, if any

Quality of Network (C/I values)

Related network features (FH, DTX, etc.)

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Coverage Design Inputs by BSNL

Coverage Thresholds

Indoor Coverage : Signal Level measured at street better than65dBm. Indoor coverage to be provided in commercial complexes,hotels,technology parks etc.

In Car Coverage: Signal Level measured at street better than75 dBm.In Car coverage to be provided in residential areas, highways, touristspots etc.

Outdoor Coverage : Signal level measured at street better than85dBm. All remaining areas to be covered with Outdoor coverage.

These are general guidelines for planning , specific areas not provided.

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Capacity Design Inputs by BSNL

Frequency spectrum available 6.2 MHz (31 channels).

Average traffic per sub for RF design : 50 mErlang.

Synthesizer frequency hopping can be used.

GOS: 2%

Existing network Database

Total No. of sites with configuration

Site details eg location(Lat-Long), Antenna height ,azimuth,

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RF Network Design

There are 2 parts to the RF network design to meet the :-

Capacity requirement Coverage requirement

For the RF Coverage Design

RFCoverage

Design

Link

Budget

Propagation

Model

Digitised

DatabasesCW DriveTesting

CustomerRequirements

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CW Drive Testing - Propagation Test

Scanning Receiver Setup - HP 7475A Receiver Example

HP 7475A Receiver

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Link Budget

Link Budget Element of a GSM Network

BTS Antenna Gain Max. Path Loss Fade Margin

LNA

(optional)

Feeder Loss

Diversity

Gain

BTS ReceiverSensitivity

ACE

Loss

BTS TransmitPower

Penetration Loss

MS Antenna Gain,

Body and Cable Loss

Mobile Transmit

Power

Mobile Receiver

Sensitivity

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Link Budget

Link Budget Example (GSM900)

UPLINK DOWNLINK

MS Transmit Power 33 dBm BTS Transmit Power 46 dBmCable Loss 0 dB ACE Loss ZMS Antenna Gain 2.2 dBi Feeder Loss 2 dBBody Loss 2 dB LNA Gain 0 dBPenetration Loss W BTS Antenna Gain 18 dBi

Slow Fade Margin X Max. Path Loss YMax. Path Loss Y Slow Fade Margin XBTS Antenna Gain 18 dBi Penetration Loss WLNA Gain 0 dB Body Loss 2 dBFeeder Loss 2 dB MS Antenna Gain 2.2 dBiACE Loss 0 dB Cable Loss 0 dBDiversity Gain 4 dB Diversity Gain 0 dB

BTS Receiver Sensitivity -107 dBm MS Receiver Sensitivity -102 dBm

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Nominal RF Design

Link Budget

Maximumpath loss

Propagationmodel

Typical siteconfiguration

Site radius

Nominal RFDesign

(coverage)

Coveragerequirements

Nominal sitecount

Coverage sitecount

Transmit Power

Antenna configuration

(type, height, azimuth)

Site type (sector, omni)

Trafficrequirements

Standard hexagon sitelayout

Friendly, candidate sites

Initial site survey inputs

Traffic sitecount

Traffic > Cov.

Cov. > Traffic

Recalculate the site

radius using the

number of sites from

the traffic requirement

Repeat the nominal

RF design

Trafficrequirements