Global System for Mobile (GSM)
Global System for Mobile (GSM) is a second generation cellular system standard.GSM is the world's first cellular system to specify digital modulation and network level architectures and services
- GSM was originally developed to serve as the pan-European cellular service and promised a wide range of network services through the use of ISDN.
- GSM's success has exceeded the expectations of virtually everyone, and it is now the world's most popular standard for new cellular radio and personal communicationequipment throughout the world
GSM Services and Features:
- GSM services follow ISDN guidelines and are classified as either teleservicesor data services
- One of the most remarkable features of GSM is the Subscriber Identity Module (SIM), which is a memory device that storesinformation such as the subscriber's identification number, the networks andcountries where the subscriber is entitled to service, privacy keys, and other user-specific information
- A second remarkable feature of GSM is the on-the-air privacy which is provided by the system.
GSM System Architecture:
- The Mobile Stations (MS) communicate with the Base Station Subsystem (BSS) over the radio air interface.
- The BSS consists of many BSCs which connect to a single MSC, and each BSC typically controls up to several hundred Base Transceiver Stations (BTSs)
GSM frame structure: GSM operations from speech input to speech output: