Distributed-queuing call admission control in wireless packet communications

Packet dropping probability is an important criterion in the performance evaluation of wireless/cellular packet communications. In the absence of an efficient call admission control mechanism packet dropping probability may increase without bounds causing undesirable speech clipping. An access-based control strategy for call admission in wireless packet communications is proposed. Packet access requests from ongoing calls are given priority over new call packet access by using a time out mechanism for new calls, that is, new calls waiting more than a given amount of time are denied access to the resource and are cleared from the system. This scheme achieves graceful degradation in packet dropping for existing calls under heavy load conditions while blocking most of the new calls. An analytical approximation for call blocking and simulation results are reported. The capacity gains in terms of Erlangs are evaluated and found always greater than the achievable statistical multiplexing gains in wireless packet networks. The capacity gains are roughly 2-3 times greater than those of traditional circuit. switched systems.