GSM comes with a complex system architecture comprising many entities, interfaces, and acronyms.
GSM network architecture elements:
The GSM architecture is divided into four main areas:
Mobile station (MS): Mobile stations (MS), mobile equipment (ME)i.e cell or mobile phones are the section of a GSM cellular network that the user sees and operates. There are two main elements of cell phone main hardware and the SIM.
- The hardware itself contains the main elements of the mobile phone; it also contains a number known as the International Mobile Equipment Identity (IMEI), accessed by the network during registration.
- The SIM or Subscriber Identity Module contains the information that provides the identity of the user to the network. It contains are variety of information including a number known as the International Mobile Subscriber Identity (IMSI).
Base-station subsystem (BSS): It consists of two elements:
- Base Transceiver Station (BTS): comprises the radio transmitter receivers, and their associated antennas that transmit and receive to directly communicate with the mobiles.
- The BTS communicates with the mobiles and the interface between the two is known as the Um interface with its associated protocols.
- Base Station Controller (BSC): It controls a group of BTSs
- It manages the radio resources and controls items such as handover within the group of BTSs, allocates channels and the like. It communicates with the BTSs over what is termed the Abis interface.
Network and Switching Subsystem (NSS): It provides the main control and interfacing for the whole mobile network. The major elements within NSS include:
Figure : GSM Architecture