Mobile communications systems and methods of operating such systems

摘要

A mobile communications system has base stations for communicating with wireless mobile devices and interconnected by an asynchronous transfer mode (ATM) communications network which includes ATM switching centres. A handover process coordinates transfer of communications with a mobile device from one base station to another as the device moves between their respective service areas. In order to avoid time-critical updating of routing tables in the switching centres in synchronization with handovers, base stations which are likely to be involved in a handover from the base station currently communicating with the mobile device are identified in advance. ATM cells being routed through the network to the mobile device are multicast to these base stations, in addition to the base station communicating with the mobile device. Thus when a handover occurs to another base station it is already receiving the cells destined for the mobile device without the need for a simultaneous change of the routing tables.