Subject: Mobile Computing

Difficulty: Medium

Marks: 4 Marks

Mobility management is nothing but the technique in which uninterrupted signal connectivity is maintained, when a mobile device changes location from cell Ci to Cj or from network Ni to network Nj .

Following are the two important points to ensure constant connectivity:

1. Infrastructure management that connects two or more cells or networks.
2. Location management and registration management by handoff when mobile devices move from one cell to another cell.The technique of mobility management is as shown in following diagram:

• Mobility Management is one of the major functionality of a GSM or a UMTS network. Mobile devices inform the cellular network, whenever it moves from one location area to another.
• Mobile devices detects the location area codes. When a mobile finds that the location area code is different from its last update, it performs another update by sending to the network, a location update request, together with its previous location, and its Temporary Mobile Subscriber Identity (TMSI) as well.
• Thus a subscriber enjoys an uninterrupted access to the network. Roaming is the fundamental mobility management procedures of all cellular networks.
• Roaming is referred as the ability for a customer to automatically make and receive voicecalls, send and receive data, or access other services, including home data services, when travelling outside the geographical coverage area of the home network, by means of using a visited network. This can be possible by using a communication terminal.
• Roaming is always technically supported by mobility management, authentication, authorization as well as billing procedures.