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March 2013

Drive Testing Basics

2013

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Your Contacts

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Sector in Cell

sites

o Each Site is divided into sectors

o Usually 3 sectors of 120 degree

o Azimuth - It is the range covered by each sector , typically 120 degree

for each sector

Sector 1Sector 2Sector 3

azimuth

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2G

3G 4G

4GLTE

GSM 2G

EDGE

UMTS

LTE

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2G

3G 4G

4GLTE

VOICE

DATA 2G

EDGE

VOICE

DATA

VOICE

DATA

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2G

3G 4G

4GLTE

2G

EDGE

9.6 kbps120 kbps

384 kbps 1.5 Mbps

10 Mbps

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Signal travels in the

form of

Electromagnetic Wave

or Frequency

Spectrum and Frequency

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GSM 3G LTE

Make sure that the Band is correctly

configured

Band Configurations

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GSM

o Single Network for Both Voice and Data

o Edge gives the data components

o With GSM the speed was 9.6 Kbps

o With Edge the speed goes to max 384 kbps

o Practical Achievable speed is 120 Kbps

Core Network

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UMTS (3G)

o Two Separate networks

o One provides Voice

o Another Provides Data

o Without HSPA upgrade the DL Speed is max up to 384 kbps

o With HSPA the DL speed is average speed is up to 2 Mbps and Max is 15 mbps in DL

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LTE(4G)

o Currently it is a data only network

o Voice will come soon

o The Voice will be on Internet just like your Vonage

o Max Speed is 300 Mbps

o Practical Speed is 10 to 15 Mbps

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Currently

LTE

3G

GSM

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Single Set of Antennas used for UMTS and LTE

Shared Antennas

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LTE UMTS GSM

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DEDICATED MODE OR ON CALL MODE

You are surfing internet

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IDLE MODE

When you are not making a call or

your phone is not updating

Any apps or retrieving an email

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IDLE MODEDEDICATED

MODE

RESELECTION REDIRECTION

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FALL BACK

LTE

3G

GSM

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FALL BACK

LTE

3G

GSM

CS FALL BACK

For Voice Call on LTE Network

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IRAT

LTE

3G

GSM

IRAT

For Data Call on LTE Network

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RESELECTION

LTE

3G

GSM

IDLE MODE

RESELECTION

TO 3G

PHONE IS IDLE

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RESELECTION

LTE

3G

GSM

IDLE MODE

RESELECTION

TO 4G

PHONE IS IDLE

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ScannerUE

Single Scanner for LTE , UMTS

and GSM

Separate Scanner for LTE and

UMTS

Acts independently of the

network

Scanner does not receive any

commands From network

Data Cards

Mobile or Smart Phones

Always receives commands

from Network and acts

accordingly

Talks to the Network and tells

it what is happening and then

executes what network

Decides

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-50 dBm -60 dBm -70 dBm

-50 dBm -110 dBm

Away from the site

SIGNAL STRENGTH

HOW STRONG THE SIGNAL IS

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SIGNAL QUALITY

HOW CLEAN THE SIGNAL IS

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SIGNAL QUALITY

As you go very far away from site not only does the strength reduceThe quality also reduces

GOOD AVERAGE BAD

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SIGNAL QUALITY

Quality Problems Quality problems can occur close to the site or far away from the site

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Telecom Terminology

GSM

Rxlevel

RxQual

BCCH TCH

UMTS(3G)

RSCP

Ec/Io

PSC

LTE(4G)

RSRP

RSRQ/SNR

PCI

Technology

Received Signal level

Received Signal quality

Channels

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Good RF Condition

GOOD RF CONDITIONS ARE DEFINED BY GOOD SIGNAL

STRENGTH AND GOOD QUALITY

GSM

RSSI > -70dB

UMTS

RSCP > -70dB

Ec/Io > -7dB

LTE

RSRP > -70dB

SNR > 15dB

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HANDOVER

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1 2 4

HANDOVER BETWEEN

SECTORS OF THE SAME

SITE THIS IS CALLED

INTRA SITE HANDOVER

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12 3 4

HANDOVER BETWEEN

SECTORS OF THE DIFFERENT

SITE THIS IS CALLED

INTER SITE HANDOVER

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Types of Drive Testing

o Site Shakedown

Single site based Drive and testing along the provided route

Coverage footprint

Each sector in the site is tested for throughput for uplink and downlink frequencies

Hand overs intra/Inter Sites.

I-Rat Handovers

o Cluster Drive

Multiple sites belonging to same location combined as cluster

Provided drive routes that are supposed to be followed while driving and testing the network

Additional tools used here would be MapInfo and Street Atlas

Precautions to be taken:

We need to ensure that the GPS is working

Verify if the phone is locked for UMTS or LTE(follow market guidelines)

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Drive Route

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Typical Drive Test setup