Overview of Global System for Mobile Communications (GSM)

Overview
　　GSM is the abbreviation for Global System For Mobile Communications. It is a digital mobile communications standard developed by the European Telecommunications Standards Institute (ETSI). GSM is the abbreviation for Global System for Mobile Communications. Its air interface adopts Time Division Multiple Access technology. Since its commercial deployment in the mid-1990s, it has been adopted by more than 100 countries worldwide. GSM standard equipment accounts for over 80% of the current global cellular mobile communications equipment market.

　　GSM is currently the most widely used mobile phone standard. More than 1 billion people in over 200 countries and regions worldwide are using GSM phones. All users can roam freely among mobile operators that have signed "roaming agreements." The biggest difference between GSM and its predecessors is that both its signaling and voice channels are digital; therefore, GSM is regarded as a second-generation (2G) mobile phone system. This indicates that digital communications have been built into the system from an early stage. GSM is an open standard currently developed by 3GPP. 　　From a user perspective, the main advantage of GSM is that users can choose between higher digital voice quality and low-cost [SMS]. The advantage for network operators is that they can customize their equipment configurations according to different customers, because GSM, as an open standard, provides easier interoperability. In this way, the standard allows network operators to offer roaming services, enabling users to use their mobile phones globally.

　　As a continuously developing standard, GSM maintains backward compatibility with original GSM phones. For example, packet-switched capabilities were only added in the Release '97 version of the standard, namely GPRS. High-speed data exchange was also introduced in the Release '99 version, primarily through the EDGE and UMTS standards.