GSM for DUMMIES.....

Mobile telecommunications is one of the fastest growing and most demanding of all telecomm. technologies.
Currently, it represents an increasingly high percentage of all new telephone subscriptions worldwide.
              Since the development of NMT 450 in 1981, many standards for mobile communication have been developed throughout the world. Each mobile standard has been developed to meet the particular requirements of the country or interest groups involved in its specification.
              GSM was designed to be platform-independent. The GSM specifications do not specify the actual hardware requirements, but instead specify the network functions and interfaces in detail. This allows hardware designers to be creative in how they provide the actual functionality, but at the same time makes it possible for operators to buy equipment from different suppliers.

GSM NETWORK COMPONENTS
The GSM network is divided into two systems. Each of these systems are comprised of a number of  functional units which are individual components of the mobile network. The two systems are:
• Switching System (SS)
• Base Station System (BSS)
In addition, as with all telecommunications networks, GSM networks are operated, maintained and managed from computerized centers.

Abbreviations:
AUC-- AUthentication Center
BSC --Base Station Controller
BTS --Base Transceiver Station
EIR --Equipment Identity Register
HLR --Home Location Register
MS --Mobile Station
MSC --Mobile services Switching Center
NMC --Network Management Center
OMC --Operation and Maintenance Center
VLR --Visitor Location Register

The SS is responsible for performing call processing and subscriber related functions. It includes the following functional units:
• Mobile services Switching Center (MSC)
• Home Location Register (HLR)
• Visitor Location Register (VLR)
• AUthentication Center (AUC)
• Equipment Identity Register (EIR)
The BSS performs all the radio-related functions. The BSS is comprised of the following functional units:
• Base Station Controller (BSC)
• Base Transceiver Station (BTS)
The OMC performs all the operation and maintenance tasks for the network such as monitoring network traffic and network alarms. The OMC has access to both the SS and the BSS. MSs do not belong to any of these systems.
To be Continued.........