GSM cellular network

GSM defines function definitions and specifies the interface requirements, but there is no limitation for the hardware to be used. This approach aims to restrict the device to work with designers and operators is to be able to get from different manufacturers. GSM network is divided into three main systems: Switching System (SS), Base Station System (BSS) and Operation and Support System (OSS).

Switching system:

Switching System is responsible for call processing and subscriber related functions. The switching system comprises the following functional units:

• ·         Home Location Register (HLR)
• ·         Mobile Services Switching Center (MSC)
• ·         Visitor Location Register (VLR)
• ·         Authentication Center (AUC)
• ·         Equipment Identity Register (EUR)

Base Station System (BSS)

Base Station Controllers (BSC) and Base Transceiver Station consists of BSS performs all operations related to radio frequency.

Operation and Support System (OSS)

Operations and Maintenance Center (OMC) is connected to all devices and BSc in switching systems. OMC shape adapted to the GSM system is called Operating Support System (OSS). OSS is a functional system that allows network operators to monitor and control the network. The purpose of the OSS in a GSM network is to provide needed customer support as regional and local operations to a reasonable cost.