Admission-control policies for multihop wireless networks

Abstract

In this paper, we investigate the admission-control problem for voice traffic in fixed-route circuit-switched wireless networks. We consider coordinate-convex admission-control policies and a “blocked-calls-cleared” mode of operation, in conjunction with the usual assumptions on the voice process statistics. These conditions result in a product-form stationary distribution for the voice state of the system, which facilitates the evaluation of network performance. However, to determine the optimal policy a large state space must be searched. We develop a recursive procedure to accelerate the evaluation of a large number of different admission-control policies, and a descent-search method to reduce significantly the number of policies that must be evaluated in searching for the optimal one. The numerical examples we present indicate that reduced blocking probability (or increased throughput) can be obtained by administering active admission control. The degree of improvement is highest in moderately overloaded traffic conditions, but it is typically small in low-capacity networks (at all loads). However, in applications where the performance measure associates different revenues or costs with the various call types, considerable improvement can be obtained when admission control is used.