GSM Network

GSM is a second generation cellular standard developed to provide voice services and data delivery using digital modulation. It was developed by Groupe Spécial Mobile in 1982 to replace incompatible analog cellular systems. GSM specifications were released in 1990 and it is now used in over 135 countries worldwide with over 1.3 billion subscribers. GSM services include teleservices like voice calls, data services like SMS and supplementary services like call waiting. The GSM network architecture consists of mobile stations, base station subsystems including BTS and BSC, and network switching subsystems including MSC, HLR, VLR and others. Future enhancements to GSM include HSCSD, GPRS and EDGE to provide higher data rates before