GSM(Global system for mobile communications)
GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile), is a standard set developed by the European Telecommunications Standards Institute (ETSI) to describe technologies for second generation (or "2G") digital cellular networks. Developed as a replacement for first generation analog cellular networks, the GSM standard originally described a digital, circuit switched network optimized for full duplex voice telephony. The standard was expanded over time to include first circuit switched data transport, then packet data transport via GPRS. Packet data transmission speeds were later increased via EDGE. The GSM standard is succeeded by the third generation (or "3G") UMTS standard developed by the 3GPP. GSM networks will evolve further as they begin to incorporate fourth generation (or "4G") LTE Advanced standards. "GSM" is a trademark owned by the GSM Association.
The GSM Association estimates that technologies defined in the GSM standard serve 80% of the global mobile market, encompassing more than 1.5 billion people across more than 212 countries and territories, making GSM the most ubiquitous of the many standards for cellular networks.
GSM Requirements
The quality of Voice in the GSM system must be better then that achieved by the 900MHz analogue systems over all the operating conditions.
The system must offer encryption of user information
The system must operate in the entire frequency band 890-915MHz and 935-960MHz.
An international standardised signaling system must be used to allow the interconnection of mobile switching center's and location registers.
Minimise modifications to the existing fixed public networks.
Design the system so handset costs are minimised
Handsets must be able to be used in all participating countries
Maximum flexibility for other services like ISDN
System should maximise the functions and services available to cater for the special nature of mobile communications.
