GSM Network Architecture

GSM Network Architecture

Network in Global System for Mobile Telecommunication (GSM) composed from several functional entity that divided to be 3 (three) parts that is: 

1. Mobile Station 
mobile station is equipment that brought by customer or that’s means the cellular telephone or mobile phone . Mobile station consist of radio transceiver, Display and Digital Signal Proccesor (DSP) and Sim Card (subscriber identity module). In global system for mobile telecommunication (GSM) calling identity doesn't related with the handphone but with sim card so, when does sim card inserted to other terminal then user will get calling and can do call back from this terminal. and can get the other customer service. Mobile equipment or handphone uniquely can be identified with International Mobile Subscriber Identity (IMEI) while sim card has International Mobile Subscriber identity (IMSI) that can identify customer. But IMEI with IMSI not interdependent so be used in individual mobility. Equally we can move sim card to other handphone.

 
 

                                                           

  Picture 1 (Mobile Station) 

2. Base Station Subsystem (BBS) 

Base Station Subsystem (BBS) be device that restrain connection between radio with mobile station. Base Station Subsystem consist of two parts that is: Base Transceiver Station (BTS) that contain transceiver radio that handle a cell or region and relate to mobile station and Base Station Controller (BSC) that have function regulates radio connection between one and several base transceiver station. Besides also base transceiver station connect between mobile station with Mobile Service Switching Center (MSC)


                                                       

         

  Picture 2 (Base Station)

3. Network Subsystem 

 Network Subsystem that be part predominantly mobile Service Switcing Center (MSC) the use to do switching network mobile user with network mobile user or permanent. Mobile Service Switching Center (MSC) also prepare connection with PSTN network and ISDN. Between functional entity this use signaling system number 7 (SS7) that used to trunk signaling in ISDN and used widely at general network now.
information about mobile station kept in two location register that be a data base. First Home Location Register (HLR) containing all administration informations from all registered customers in GSM network alongs with location from mobile station. Location from a mobile station kept in the form of Mobile Station Roaming Number (MSRN). while second Visitor Location Register (VLR) contain of selected administration information from Home Location Register (HLR) need to call control and permission for user service subscribe to every user. Other register that used to autentikasi and security Equipment Identity Register (EIR) that be list containing data base mobile station valid in GSM network identifikasi via number imei. while autenthication center protection data base that keep copy PIN (Personal Identity Number) that used to autentifikasi.