Cellular telephony and mobile IP networks provide voice and data services to the users with mobility. To deliver services to the mobile users, the network is capable of tracking the locations of the users, and allowing user movement during the conversations or data sessions. These capabilities are achieved by the location management when the mobile terminal is on idle mode and handover management when it’s active (in conversation or in data session).
A location (or routing) area is a set of base stations grouped together. The location update procedure allows a mobile device to inform the cellular network, whenever it moves from one location area to the next. When a subscriber is paged in an attempt to deliver a call or SMS, the fixed network ask into the system
data base about their actual position.Then a message is broadcasted in all set of cell where the mobile terminal is roaming in.
Handover is the procedure that transfers an ongoing call from one cell to another as the user’s moves through the coverage area of cellular system. Different types of handover have defined according to degree of connectivity, the handover execution and the implication of the fixed network.
In the cellular networks several cells conforms a location (or routing) area and the location register has two levels of hierarchical structure: the main register and a copy or extension of that. Cellular IP does not scale to a global level, but it provides fast smooth handoffs on a local scale.
Mobile IPv4 or IPv6 are designed to solve macro mobility issues by routing and tunnelling. Routers connects to databases, which maintains information about mobile node’s current location, in order to implement macro and micro mobility. Mobile IP is not appropriate for cell-granularity, but can provide global mobility support.