MS (Mobile
Station)
·
Responsible
for voice encoding and transmition
·
Responsible
for the frequency & time synchronization of the radio channel
·
Responsible
for voice encryption – decryption
·
Capable
of metering the power of the cell which is useful for HANDOVER function
·
Contains
the IMEI (International Mobile Equipment ID)
MS contains a card which is called SIM (Subscriber ID Module)
SIM is a
portable smart card with memory that stores:
§ IMSI (International Mobile Subscriber ID)
§ Ki authentication parameter
§ A3 & A8 authorization algorithms
§ Kc encryption key
§ TMSI
(Temporary Mobile Subscriber ID)
§ LAI (Location Area ID)
§ RAI (Routing Area ID)
BSS (Base
Station SubSystem) = BTS + BSC
BTS (Base
Transmitter Station)
·
Handles
the radio interface
·
Receives
data transcoding
·
Responsible
for voice encryption – decryption
·
Responsible
for “up Line” radio channel power
measurement
BSC (Base
Station Controller)
·
Provides
control functions & physical links between BTS and MSC
·
Responsible
of monitoring and controlling BTS
·
Responsible
of radio channel management
·
Responsible
of switching between BTS and MSC
NSS (Network
Switching Subsystem) = MSC
+ GMSC +HLR + VLR + AuC + EiR + SCP
MSC (Mobile
switching Centre)
·
Responsible
for switching between PLMN and PSTN
·
Responsible
for MS “Handover” among BSCs , as well as allocating – deallocating radio
resources from Old to New BSC
·
Responsible
of Paging function for incoming call to Mobile Network
·
Provides
the Billing records
GMSC (Gateway
Mobile switching Centre)
The Gateway MSC (G-MSC) is the MSC that interfaces
with the PSTN. All mobile to mobile calls and PSTN to mobile calls are routed
through a G-MSC.
HLR (Home
Location Register)
·
Stores
subscriber’s information of all Subs which are registered in this geographic
area
·
Stores
IMSI
·
Stores
MSISDN (Cellular number of the subscriber)
·
Stores
VLR address
·
Subscription’s
information (services)
·
Refers
to authentication centre for getting “Ki” which is the authorization key
·
HLR
called upon by MSC when a call comes from public (land line) to cellular
network
VLR (Visitor
Location Register)
·
Keeps
the database that contains subscriber’s parameter and location information for
every mobile subscriber which is in this geographical area that is being
controlled by this VLR
·
IMSI
·
Copy
of HLR subscriber’s information
·
Generates
a TMSI for all subscribers which are located in this area.
·
Contains
LAC
·
Provides
the necessary data to MSC for routing
AuC (Authentication
Centre)
·
Stores
the SRES (signed response) for authentication of mobile equipment
·
Stores
the “Ki” (Subscriber authentication key)
·
Generates
the “Kc”
·
Provides
Random numbers, SRES and Kc on HLR request to authenticate a mobile in the
network
EIR
(Equipment Identity Register)
·
Stores
IMEI of all mobile equipment in the market
·
Keeps
a white list of IMEI that refers to “Good” phones
·
Keeps
a black list of IMEI that refers to “stolen” phones
·
Keeps
a grey list of IMEI that refers to “on observation” phones