24-03-2010, 08:02 PM
what is gsm;information about BSC, MSC, communication links like a, b interface
24-03-2010, 08:02 PM
what is gsm;information about BSC, MSC, communication links like a, b interface
30-10-2010, 02:48 PM
Please visit the below given thread for more details
https://seminarproject.net/Thread-gsm-ar...2#pid29212
19-10-2012, 11:02 AM
GSM Architecture
GSM.pdf (Size: 323.01 KB / Downloads: 496) Network Switching Subsystem (NSS) Fundamentally, the network and switching subsystems (NSS) is responsible for call connection, supervision and release operations between calling and called stations, where one or both of them are mobile stations (MS). Other functions include: • Handling short messages and packet data (email, fax and a variety of notifications) • Providing ‘bearer’ channel for data communications • Maintaining database of its own users as well as visitors • Variety of authentication and encryption • Gateway to PSTN, other mobile networks and data networks including the Internet Home Location Register The home location register (HLR) is a database used for storing and managing subscriptions. Generally a PLMN (Public Land Mobile Network) consists of several HLRs. The first two digits of the mobile directory number (e.g. 0171 2620757) are the number of the HLR where the mobile subscriber is stored. The data includes permanent data on subscribers (such as subscriber's service profile) as well as dynamic data (such as current location and activity status). When an individual buys a subscription from one of the GSM operators, he or she is registered in the HLR of that operator. Mobile Switching Center and Visitor Location Register The mobile switching center (MSC) performs the telephony switching function. A mobile station must be attached to a single MSC at a time (either homed or visitor), if it is currently active (not switched off). The visitor location register (VLR) is a database attached to an MSC to contain information about its currently associated mobile stations (not just for visitors). Note: A basic switch (that is a PSTN/ISDN switch) already has a database for its telephone connections. However, it is not designed to include visitors since a visitor has telephone number that does not belong to this switch. That is why a separate VLR is needed. An MSC, with the help of the HLR, allocates a visitor a ‘local’ telephone number (the MSRN), which is not currently allocated to anyone. This allocation is temporary (like visitor ID card). The VLR stores the MSRN as mobile station’s telephone number (along with other information). However, VLR also stores some information like ‘security triple’ (authentication and encryption information) for each mobile station that are currently attached to the MSC. A VLR stores such information not only for its visitors but also for the homed mobile stations. From this perspective VLR is for homed mobile stations as well. |
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