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RF Planning and Drive Test RF Planning and Drive Test

for BSNL internal circulation only

RF Planning and Drive Test RF Planning and Drive Test


A cell can be defined

as the area covered

by one sector

Main Elements of Radio


Main Elements of Radio

Network•Mobile station

•Base Transceiver Station

RF DESIGN REQUIREMENTS

• The RF design inputs can be divided into

– Capacity requirements

• Erlang per subscriber during the busy hour–


• Quality of service for the air interface, in terms GoS

– Coverage requirements

• Target coverage areas.

• Coverage area probability

• Penetration Loss of buildings and in-cars

• Determine number of cells required for capacity

by using Erlang formula.

CAPACITY AND COVERAGE


by using Erlang formula.

• Determine number of cells required for coverage

by using propagation model.

ERLANG

• One erlang ( Erl) is defined as the amount of

traffic generated by the user when he or she

uses one traffic channel for one hour.


ERLANG TABLES

• Commonly used Erlang tables are

– Erlang B

– Erlang C

• Erlang B assumes that if calls cannot go through


then they get dropped (i.e. no queuing possible).

• Erlang C considers that if a call does not get

through then it will wait in a queue.

ERLANG TABLES

• These tables give information about the traffic

generated by X No. of TRXs for different Grades

of Service.


POSSIBLE CHANNEL COMBINATIONS

RT 0

Timeslots

RT 1

BCCH CCCH TCHSDCCH TCH

0 1 2 3 4 5 6 7

TCH TCHTCH


CM

CC SMS SS

RT 1

RT 2

RT 3

TCH

SDCCH

TCH TCH TCH TCH TCH TCH TCH

TCH TCH TCH TCH TCH TCH TCH TCH

TCH TCH TCH TCH TCH TCH TCH

FREQUENCY RE-USE

• Frequency re-use factor depends on

– the average number of the transceivers

– the total number of frequencies.


FREQUENCY RE-USE FACTOR

• If there are 3 TRX that are used per base station

and the total number of frequencies available is

27.The total number of frequencies available for


re-use is 27/3 = 9

• There are few theoretical models and many

empirical models to predict the propagation path

loss.

PROPOGATION MODELS


loss.

• Propagation models should be applied with

caution .

• Network planning tools will combine these

models with terrain data.

PROPOGATION MODELS

• For Macro Cell

– Okumura-Hata model

• For Micro Cell

– Walfisch-ikegami model


– Walfisch-ikegami model

PROCESS OF RADIO NETWORK

PLANNING

• Collection of the input parameters

• Pre planning

• Site survey

• Frequency allocation


• Frequency allocation

• Parameter planning

• The final radio network plan involves rest of the

parameters like power budget calculations and

considering path loss calculations.

OPTIMISATION

• Optimization involves monitoring, verifying and

improving the performance of the radio network.


WHAT IS OPTIMIZATION


OPTIMISATION

• Power amplifiers are located near the

transmission antennas.

• The boosters are located near the base station.


DIVERSITY

• Diversity is the most common way to improve

the reception power of the receiving antenna.

• Major diversity techniques are

– space diversity

– frequency diversity


– frequency diversity

– polarization diversity

(In our field polarisation diversity is being used)

RADIO NETWORK PLANNING

AND OPTIMIZATION

o Study of methods required for optimization:

o Traffic estimation in terms of erlangs

o Configuration of Time slots of TRX

o Calculation of frequency re use factor

o Application of suitable propagation model


o Application of suitable propagation model

o Methods to improve signal received by MS

o Study of RRM ( Radio resource management)

o Study of KPI’s( Key performance parameters)

MS BTS MSCBSC

RIL3 - CM

RIL3 - MM

RIL3 - RRSCCP

BSSMAP

DTAP

MM

TCAP

DTAP

CM

U

PSCCP

MAPI

S

SCCP

BSSMAP

BTSM

RIL 3-RR

BTSMRR


LAPD m

Layer 1 Layer 1

LAPD m LAPD

Um A bis A link BCDEFG

MTP

Layer 1Layer 1

GSM Signaling Protocols Overview

LAPD MTP

RADIO RESOURCE MANAGEMENT

• The radio resource management (RRM) is the

functions related to

– mobile location updation

– communication management issues such as


– communication management issues such as

handover and roaming procedure handling

LINK PROTOCOLS

• To execute these management functions,

information flow (traffic and signalling) takes

place via three protocols, known as link


protocols .

LINK PROTOCOLS

• LAPDm is present over the MS-BTS connection

• LAPD over the BTS-BSC connection.

• MTP is used for signalling transport over the


SS7 network.

STUDY OF KPIs

• Once a radio network is designed and

operational, its performance is monitored.

• The performance is compared against chosen

key performance indicators (KPIs).


• After fine-tuning, the results are then applied to

the network to get the desired performance.

STUDY OF KPIs

• KPls can be subdivided according to the areas of functioning, such as – area level

– cell level

– TRX level.

• Area-level KPls can include


• Area-level KPls can include – SDCCH requests

– dropped SDCCH total

– dropped SDCCH Abis failures

– outgoing MSC control handover (HO) attempts

– outgoing BSC control HO attempts

– intra-cell HO attempts, etc.

DRIVE TEST PROCESS

• Selection of the 'live' region of the network

• Selection of the drive testing path.

• To have the appropriate kits including


– Mobile equipment (usually three mobiles)

– Drive testing software (on a laptop)

– A GPS (global positioning system) unit.

USB2 USB1

Short call Long Call

USB3

Idle

Drive Test Equipments for Voice & PS callTools

1. Scanner

2. Drive Test

Software

3.UE

4.PC

5.GPS

DRIVE TEST TOOL PHYSICAL SET UP


Com 1

scanner

USB3

GPS

Data Card

PS

DRIVE TEST PROCESS

• Two mobiles are used to generate calls with a

gap of few seconds (usually 15-20 s).

• The third mobile is usually used for testing the


coverage.

• It makes one continuous call, and if this call

drops it will attempt another call.

DRIVE TEST PROCESS

• To collect enough samples at a reasonable

speed and in a reasonable time.

• If there are lots of dropped calls, the problem is


analysed to find a solution for it and to propose

changes.

OPTIMISATION SOLUTION

• Moving antenna locations

• Altering antenna heights

• Changing ARFCNs


• Antenna orientation adjustment

• Rectifying the faults in the steps followed before

finalisation of Radio network planning.

DRIVE TEST TOOL

• TEMS offers solutions for

– Planning

– Development

– Optimizing


– Optimizing

– Troubleshooting

– Expanding mobile networks

• Optimized networks mean lower operational

costs.

DRIVE TEST TOOL

• TEMS products allow efficient monitoring,

diagnosing and benchmarking in order to make

best use of available resources.


• They also enable engineers to troubleshoot

problems quickly.

TEMS CELLPLANNER UNIVERSAL

• TEMS Cell Planner Universal is Ericsson´s tool

for mobile radio network planning.

• It is a

– highly graphical


– highly graphical

– easy-to-use

– PC-based tool for design

– Realization

– Optimization of mobile radio networks.


• It assists the user in a number of complex tasks,

including

– network dimensioning

– traffic planning


– traffic planning

– site configuration

– frequency planning.


• It supports for

– WCDMA

– GSM 850,GSM 900,GSM 1800,GSM 1900

– iDEN


– CDMA,CDMA2000 1xRTT

– TDMA/AMPS

– NMT 450, NMT 900

– TACS, and E-TACS.

– GPRS and EGPRS (EDGE) in GSM system.

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