Performance analysis and estimation of call admission policy parameters for multiple traffic classes in wireless ATM networks

In this paper we propose an admission control policy for wireless ATM networks. The policy is based on the well know method, threshold-based guard channel policy. We modify it to deal with two different types of traffic classes; namely: CBR traffic class and ABR traffic class where we assume two different thresholds, one for each traffic class. In addition, we propose to buffer the handoff ABR calls if no free channels are available rather than rejecting them. For handoff CBR calls, we propose two methods, namely: a blocking method and a preemptive method. For the blocking method, we reject the handoff CBR calls if no channels are available. For the preemptive method, we accept handoff CBR calls in case of no available channels if ongoing ABR calls exist where we buffer one of them in order to serve the handoff CBR call. We study the effect of the thresholds, buffer size and the effect of the proposed methods on call blocking probabilities. Based on these results, we developed an algorithm that uses the proposed policy to estimate the appropriate thresholds and buffer size which meet a certain required call blocking probabilities for each traffic type.