Decentralised call admission control for wireless ATM

A new mobility-specific call admission control (CAC), using a decentralised approach, is introduced. This new CAC reduces the load on the mobility-supporting (MS) ATM switch and prevents it from becoming a bottleneck in the system. The proposed decentralised CAC is executed partially in the serving access point (AP) and partially at the MS-ATM switch. An estimate of the network traffic load is derived from the measured traffic at the specific ATM connection during a fixed period of time. The available bandwidth is calculated at each node and is updated regularly, for use by the generic CAC to route new incoming calls. Call acceptance is decided, based on the call dropping probability. Numerical results show considerable improvement in the CAC responsiveness and network throughput. They also show that the estimate becomes more accurate under heavy traffic conditions