Design of soft handover protocol for mobile ATM networks

Handover or handoff control process is required to dynamically support active connections during the migration of a Mobile Terminal (MT) from one Access Point (AP) to another. This feature is critical for mobile multimedia services delivered to a Wireless ATM-WATM terminal, as well as for efficient support of current Personal Communication Systems (PCS)/Cellular System on an ATM infrastructure. Handover requires network signaling to maintain the communication link and may result in cell loss due to cell misrouting and/or misordering. Several hard handover schemes were proposed, these schemes have some potential problems such as the ping-pong phenomenon, the possibility of information loss and poor QoS. This paper presents a soft handover solution for Mobile ATM networks to overcome these limitations. Four soft handover schemes are presented based on different configurations of the mobile ATM networks and accordingly the way of achieving the matching of the ATM cells for both the upstream and downstream traffic.