Analysis of performance of GSM networks 

Some networks are achieving high spectrum utilisation, even when a 

combination of Macro and 15% Micro is used. 

Other networks performance rating indicates lack of investment in network 

capacity. 

Most of the networks do not employ hierarchical layers techniques and half 

rate codecs; the major networks in the country are starting to employ small 

cells and some micro cells but this is not being done on the basis of 

structured layers. 

The best Erlangs per MHz per Sq Kms achieved over an area of 25 Sq 

Kms is 22 while over an area of 8 Sq. kms is 38. 

The best networks are currently operating with a maximum cell packing 

density of about 13 per sq km in approximately 25 Sq Kms area and 23 

per Sq Kms over an area of 8 Sq Kms. 

In certain networks, there are also variations in deployment on account of 

specific topography and municipal laws. 

3.2.2.3 

Impact of utilisation of advanced techniques in GSM 

networks 

A number of techniques and system features are available that improve 

system quality and spectral utilisation.  These are primarily concerned with 

speech performance, which despite the growth of data services, is likely to 

remain the dominant service for GSM.  Additionally, a number of 

developments are underway that in connection with the system features are 

claimed to have the potential to increase system capacity within the GSM  

frequency bands including 1800 MHz band. 

The techniques of spectrum utilisation and quality enhancement techniques 

are briefly discussed below: 

- 

1) Baseline 

GSM 

Speech 

enhancement   Frequency Hopping, 

Power Control, Discontinuous Transmission (DTX) 

- 

2) 

Frequency Re use and Partitioning Methods   Hierarchical 

Structures/Layers are deployed in GSM networks to enhance 

capacity. 

These techniques divide the radio spectrum into blocks that can be assigned 

to separate layers in the network each with different frequency re use.  A 

higher layer with a  loose  re use factor ensures full contiguous coverage 

(called an overlay layer) whilst other lower layers, which need not be 

contiguous in coverage and have a very tight re use and hence high capacity 

(underlay layer).  Mobiles are directed to the appropriate layer by the network, 

depending on their location in the network and speed of travel.  There are 

many different implementations of re use partitioning that are proprietary to 

the equipment vendors, e.g. Concentric Cells   Motorola, Multiple Re use 

Patterns   Ericsson, Intelligent Underlay overlay   Nokia 

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