GSM Cellular System - almadar-rd.lyalmadar-rd.ly/summer_training_2016/Day4/2-GSM-Cellular-System.pdf · GSM Cellular System. ... •Base Transceiver Station BTS ... Base Transceiver
Post on 07-Apr-2018
239 Views
Preview:
Transcript
Network architecture
10 8/3/2016
• Switching System SS: responsible for performing all processing and subscribe related function.
• Base Station System: performs all radio-related function.
• Operation and Maintains Centre OMC: monitoring network traffic and network alarms.
• Mobile System: terminal equipment.
Mobile Equipment ME
12 8/3/2016
• IMEI: 15 –digit number
• First 6 digits type approval code.
• Next 2 digits assemble code.
• Next 6 digits S/N.
• Last digit spare.
Subscribe Identity Module SIM
13 8/3/2016
• SIM : an electronic microchip for storing information.
• Contains: CPU, Memories (RAM, ROM and EPROM).
• Small computer!!
Subscribe Identity Module SIM
14 8/3/2016
• SIM : stores information:
Subscriber identification.
Charging
Security.
Identity numbers
15 8/3/2016
• IMEI
• Mobile Station ISDN number (MSISDN): 15 digit
• International Mobile Subscriber Identity (IMSI):
Identity numbers
16 8/3/2016
• Temporary Mobile Subscriber Identity (TMSI): use instead of IMSI
• Mobile Station Roaming Number (MSRN)
Base Transceiver Station BTS
19 8/3/2016
• Ericsson calls it RBS Radio Base Station.
• Contains RF transmission equipment.
• Each BTS consists from one or more Transceiver TRU.
• Performs channel coding, ciphering and modulation.
Base Station Controller BSC
20 8/3/2016
• It carries all control function in BSS
• Paging
• Channel allocation
• Dynamic power control
• Handover
• Frequency hopping
Connecting BTSs with BSC
21 8/3/2016
• A link between the BTS and BSC is required to carry the Traffic and the signalling.
• Usually microwave links are used to connect BTSs with BSC.
• Any other type of connection can be used. (Optical fiber ).
Switching System
27 8/3/2016
•MSC: The MSC performs the telephony switching functions for the mobile network. It controls calls to and from other telephony and data systems, such as the Public Switched Telephone Network (PSTN), Integrated Services Digital Network (ISDN), public data networks, private networks and other mobile networks.
•GMSC: Gateway functionality enables an MSC to interrogate a network’s HLR in order to route a call to a Mobile Station (MS). Such an MSC is called a Gateway MSC (GMSC).
Home Location Register HLR
28 8/3/2016
•HLR: The HLR is a centralized network database that stores and manages all mobile subscriptions belonging to a specific operator. The information stored includes:
Subscriber identity (IMSI, TMSI, MSISDN)
Subscriber supplementary services
Subscriber location information
Subscriber authentication information
• The HLR can be implemented in the same network node as the MSC or as a stand-alone database. If the capacity of a HLR is exceeded by the number of subscribers, additional HLRs may be added.
Visitor Location Register VLR
29 8/3/2016
• It contains almost the same information as HLR.
• When user moves from MSC to another MSC, the new MSC registers the user in VLR.
Authentication Center AUC
30 8/3/2016
• The main function of the AUC is to authenticate the subscribers attempting to use a network.
• The AUC is a database connected to the HLR which provides it with the authentication parameters and ciphering keys used to ensure network security.
Equipment Identity Register EIR
32 8/3/2016
• Because SIM and ME are separated in GSM, a separate authentication process for ME is needed.
• EIR is centralized database for IMEI.
• EIR contains:
White list (valid ME equipment).
Black list (stolen ME).
Gray list (faulty software).
top related