Global_System_for_Mobile_Communications

Global System for Mobile Communications GSM stands for Global System for Mobile Communications and is the most popular standard for mobile phones in the world. GSM phones are used by over a billion people across more than 200 countries. The ubiquity of the GSM standard makes international roaming very common with "roaming agreements" between operators. GSM differs from its predecessors most significantly in that both signaling and speech channels are digital, which means that it is seen as a second generation (2G) mobile phone system. This fact has also meant that data communication was built into the system very early. GSM is an open standard which is developed by the 3GPP. The key advantage of GSM systems from the point of view of the consumer has been early delivery of new services at low costs, for example text messaging was developed first for GSM, whilst the advantage for network operators has been the low infrastructure cost which is caused by open competition. The primary disadvantage has been that GSM's radio network is based on TDMA technology, which is considered less "technologically advanced" than competing CDMA based systems, though practical performance figures are rather similar. GSM has remained backward compatible with the original GSM phones, at the gsm, global, system, mobile, communications, data, network, phones, frequency, been, services, mhz, gprs, coverage, cells, networks, phone, operators, standard, cell, called, based, antenna, voice, specifications, information, indoor, however, europe, cover, countries, 900, using, systems, subscriber, sim, radio, packet