GSM Architecture Flashcards
Name the SIM contents
Phonebook IMSI TMSI Authentication and Encryption keys Services available MSISDN
Expand MSISDN
Mobile Station Intergated Services Digital Network Number
Breakdown an MSISDN Network Number
First 2 digits: Country code
Next 3 digits: National Destination Code
Next 7 digits: Serial Number
44 772 5864765
What is an IMSI?
Held on the SIM card, it contains all subscriber information. E.g. Billing information
Breakdown an IMSI number
First 3 digits= Mobile Country Code
Next 2 digits= Mobile Network Code
Next 9 digits= Operator specific
Where is the TMSI sent?
Between the MS and the Network.
What is an IMEI?
International Mobile Equipment Identity. It is allocated to each MS and known by the EIR.
Breakdown an IMEI number
First 8 digits: Type Allocation Code
Next 6 digits: Serial Number
Last digit: Check Digit
When is the IMEI broadcast?
Powering on the MS
Change of SIM card
What is the BTS commonly referred as?
Mobile Phone Mast
What functions does the BTS provide?
RF carriers Modulation/Demodukation of RF carriers Data processing Error coding Ciphering Channel mapping
Name the BTS antenna types
Omni Directional and Sectored
Name the functions of the BSC
Establishes and clear radio connections MS power control MS timing control Performs hangovers Stores information
What does the MSC act as?
The brains of the network and controls the BSCs
What is held in the Home Location Register?
IMSI MSISDN MSRN Last known LAI location Billing information
