TABLE OF CONTENTS Mobility in wireless communication systems is a unique characteristic which enables roaming subscribers to receive the same services from foreign systems while on the move, a characteristic not available to subscribers of the wired public switched telephone networks. Mobility is concerned with issues allowing the serving network to be always in contact with the subscribers and tracking the up-to-date locations of the subscribers to relay their incoming calls. Mobility is also concerned with subscriber billing for the services provided by the foreign systems.
Mobility includes two essential tasks: location registration and handoff procedures. Registration is the process by which the mobile terminal notifies the home network of its location in order to enable it to efficiently page the terminal for any incoming calls. Registration also allows the home network to determine which paging channel the mobile terminal is monitoring and the capabilities of the mobile terminal.
Handoff, on the other hand, is the procedure of automatic channel change which occurs when the subscriber moves from one cell to another. However, since cells in the IS-95A systems share the same channel, handoff procedures only require changing base stations as the subscriber moves from an old to new location area.
Roaming agreement contracts between service providers and billing mechanisms are essential in providing services such as the ability to make/receive calls, i.e. the inter-networking allowing the call to continue uninterrupted when the mobile subscriber crosses the boundary between two networks; provision for Short Message Service (SMS); provision for...
