1.5 GSM Development and Characteristics

Originally GSM referred to the European working party set up to establish a new standard
(‘Groupe Speciale Mobile’) but was later amended to reflect a more global application (Global
System for Mobile communications).

Cellular Structure

• The aim of a cellular system is to make best use of the
available frequencies (spectrum)
• The cellular structure allows the re-use of
frequencies across the network
• Planning the pattern of this frequency re-use is a
key part of the system design
• Hexagonal pattern best represents interlocking grid of cells

GSM Planning

• Key Network planning parameters

• Coverage – getting a usable radio signal to all areas in the
network
• Capacity – handling the call traffic generated by the subscribers
• Quality – low interference, few calls dropped etc.

• Optional parameters requiring planning

• Hierarchical Cell Structures (macrocell/microcell)
• Frequency Hopping
• Discontinuous Transmission
• Power Control

• Subscriber/traffic analysis

• Capacity limited by number of TRX’s