A center-controlled dynamic rerouting scheme for fast and reliable handover in mobile ATM networks

This paper proposes a scheme for fast and reliable handover that uses dynam ic rerouting controlled by a call setup control station (CCS) operating in mobile asynchronous transfer mode (ATM) networks. The CCS selects appropria te rerouted path and crossover switch (COS), and remotely controls the new path's setup. This omits crossover switch discovery process, and makes fast handover possible. The CCS can select the appropriate rerouted path becaus e it directly and with little delay collects information about the state of links such as traffic loads, quality-of-service (QoS) parameters, and disc onnection or restoration of links advertised from every ATM switch in its d omain. This reduces blocking and congestion, and makes reliable handover po ssible. The CCS accepts a handover request message for either backward or f orward handover, and can remotely control the new path's setup in the same manner for either handover. The scheme provides forward handover when the r adio propagation conditions deteriorate unpredictably. This paper also show s sequences of call origination, connection pre-establishment, and route-ch ange in our proposed scheme, and illustrates operation of the CCS and the A TM switches.