OR

Draw architecture of IS-95 system and state function of any two blocks.

Diagram:

CSS- Cellular Subscriber Station

BS-Base station

MSC- Mobile switching center

HLR-Home location registers

EIR-Equipment identity register

VLR- Visiting location registers

AC- Authentication center

Explanation :

Cellular Subscriber station:It is defined as a station in cellular radio service which is used when in motion at an unspecified location.

Home Location Register: Permanent database about mobile subscribers in a large service area.Database contains subscriber & location information. Database contains prepaid/postpaid, roaming restrictions, supplementary services.

Authentication Center: A unit called the AC provides authentication and encryption parameters that verify the user's identity and ensure the confidentiality of each call. The AC protects network operators from different types of fraud found in today's cellular world

Visitor Location Register: Temporary database which stores customer information for each roaming subscriber visiting the coverage area of particular MSC. It updates whenever new MS enters its area, by HLR database. It controls the mobiles roaming in its area.

Base station: A fixed station in a mobile radio system used for radio communication with mobile stations. Stations are located at the center or on the edge of a coverage region and consists of radio and transmitter and receiver antennas mounted on a tower

Mobile Switching Center: It co-ordinates the activities of all the base stations and connects the entire cellular system to the PSTN. A typical MSC handles 100,000 cellular subscribers and 5,000 simultaneous conversations at a time, and accommodates all billing and system maintenance functions as well.

EIR : The Equipment Identity Register (EIR) is a database that contains a record of the all theCellular Subscriber stationthat are allowed in a network as well as a database of all equipment that is banned, e.g. because it is lost or stolen.