GSM ENTITIES
INFORMATION STORED IN SIM CARD
BTS(BASE TRANSCEIVER STATION
BSC(BASE STATION CONTROLLER)
MSC(MOBILE SWITCHING CENTER)
-to store contact information, including names and numbers
-Short Message Service messages received and saved are also stored
-International Mobile Subscriber Identity number
-Mobile Subscriber Integrated Services Digital Network number.
GMSC(GATEWAY MSC)
-Channel encoding and decoding
-Burst formatting and interleaving
-Encryption and decryption
-GMSK modulation and demodulation
-Creation and transmission of BCCH
-Allocates a channel for the duration of a call
-Handles call set up
-Maintains the call
-Monitoring quality
-Control one or more BTSs
-Logging calls, controlling calls and switching calls
-Interface with PASTN, ISDN, PSPDN(Packet Switched Public Data Network)
-Mobility management over the radio network and other networks
-Billing information
-Gateway functionality enables an MSC to interrogate a HLR in order to route a mobile terminating call
-It is not used in calls from MSs to any terminal other than another MS
-Find and interrogate HLR for roaming number
-Route the call according to the interrogation