Mobile networks

Revision as of 13:47, 10 October 2012

A mobile network is composed by the following parts:

• Mobile Station (MS)
• The base stations subsystems (BSS)
• The network and switcing subsystem (NSS)
• The operations and support subsystem (OSS)

Mobile Station (MS):

• the mobile equipment (Ex: phone)
• the SIM (Subscriber identity Module) card that uniquely identified the card by the IMSI (International Mobile Subscriber Identity).

The base station subsystem (BSS):

• base station (BTS) - it defines a cell in the network
• base station controller (BSC) - controls a group of BTSs. Does handoffs, frequency hoppings, exchange functions and power control over each managed BTS

The network and switching subsystem(NSS)

• Home location register (HLR)
  • holds all subscribers in a network.
  • keeps subscriber specific information like MSISDN, IMSI, current location of the MS, roaming restrictions, additional features.
  • the is only one HLR per network
• Authentication Center (AuC)
  • handles the authentications and encryption in a network.
  • it is typically located with the HLR
• Equipment inquiry register (EIR)
  • tracks of handsets on the network using the International Mobile Equipment Identity (IMEI).
  • there is only one EIR per network.
  • It is composed of three lists. The white list, the gray list, and the black list.
• Mobile switching center (MSC)
  • handles call routing, call setup, and basic switching functions.
  • does inter BSC handoffs and coordinates inter MSC handoffs
• Gateway Mobile Switching Center (GMSC)
  • type of MSC that is a gateway between two networks
  • is is used when sending a call from a subscriber to the PSTN
• Visitor location register (VLR)
  • is associated a local area(LA).
  • Keeps information similar to the one in the HLR for the users in it's current local area