GSM communication system

GSM system (Global System for Mobile Communication), also known as Global System for Mobile Communications (GSM).
GSM mobile communication system is mainly to exchange sub-system (MSS), Base Station Subsystem (BSS) and mobile station (MS) has three major components, as shown. BSS and MSS in which the interface between A for the interface, BSS and the interface between the MS for the Um interface. GSM specification of the system interface and the A's have a clear interface Um, that is to say, A and the interface Um interface is an open interface.
(4) GSM system
(4) -1. Mobile Switching subsystem MSS
To complete the exchange of information, information management, follow-up call, the number of management functions.
(4) -2. BSS Base Station Subsystem
BSS is a certain system of wireless coverage in areas controlled by the MSC, MS communicate with the system, the completion of the distribution channel, the user's access and paging, information transmission and other functions.
(4) -3. Mobile Station MS
MS is a GSM mobile system equipment, which is composed of two parts, mobile terminals and customer identification card (SIM card). Mobile terminal "machine", it can complete the voice coding, channel coding, information encryption, modulation and demodulation of the information, transmitting and receiving information. SIM card is the "people", which we are similar to those used by IC cards, also known as smart cards, customer identification requirements for certification have all the information and the implementation of some of the secrecy and security-related information in order to prevent illegal customer Access to the Internet. SIM cards can also store and network management and customer-related data, only to insert SIM card mobile terminals can access into the net.
(4) -4. Operation and Maintenance System
GSM sub-system also includes operation and maintenance sub-system (OMC), the entire GSM network management and monitoring. Through the achievement of its GSM network in various parts of the functions of surveillance, the report states, the fault diagnosis functions.
A) GSM network system
GSM's history can be traced back to 1982, at the time, the four countries to the Nordic CEPT (Conference Europe of Post and Telecommunications) submitted a proposal that calls for 900MHZ band of European norms of public telecommunication services in order to create a unified pan-European cellular systems. In the same year, set up a special team to mobile communications (GSM-Group Special Mobile). In the 1982 ~ 1985, the focus of discussion is the development of analog cellular networks or the development of standards for digital cellular network standards, until the decision in 1986 to develop standards for digital cellular network. In 1986, in Paris for different companies, different options of the system (8) were compared, including on-site test. May 1987 selection of narrow-band TDMA program. At the same time, 18 countries signed a memorandum of understanding with each other to reach an agreement to fulfill the norms. In 1988 promulgated the GSM standard, also known as the pan-European digital cellular communications standard. At this stage, GSM has two parallel systems: GSM900 and DCS1800, the two systems function the same as the frequency is different. In the GSM recommendations, did not provide the hardware, only to the development of feature Interface and detailed provisions to facilitate such different products to communicate with each other. A total of 12 recommendations GSM system.
The main components of the system 1.GSM
GSM digital cellular communication system can be divided into the main part of the mobile station, base station subsystems and network subsystems. Base Station Subsystem (the base station BS) from the base station transceivers Taiwan (BTS) and base station controller (BSC) component; network sub-system by the Mobile Switching Center (MSC) and Operation and Maintenance Center (OMC) as well as the location of the site Register (HLR), visit Location Register (VLR), Authentication Center (AUC) and equipment register marks (EIR), and other components.
2.GSM the region, number, address and identification
1) region
From the geographical scope of view, GSM system is divided into GSM service area, public land mobile network (PLMN) business areas, Mobile Switching Control Area (MSC area), the location of the area (LA), base stations and residential areas.
* GSM service area
By all members of the GSM network, mobile services in the region as long as the user, the system will be able to get a variety of services, including the completion of the international roaming.