Adaptive admission control in wireless multimedia networks under non-uniform traffic conditions

Abstract

Adaptive admission control in cellular wireless networks reserves bandwidth for handoff calls, which is proportional to the traffic intensity in the surrounding cells. This paper analyzes performance (QoS) of the adaptive admission algorithm in the presence of nonuniform traffic conditions in the network. We model the performance of small, moderate, and large hot-spots, and analyze average cell capacity utilizations and their derivatives when the hot-spot new call arrival rate is growing and surrounding cells operate at the constant load. The analysis shows that under sufficient bandwidth reservation, derivatives of the hot-spot cell capacity utilizations converge to zero for hot-spot call arrival rates larger than twice the nominal load. Since the average utilization is the linear combination of all the state probabilities of the Markov chain, the convergence of its derivative to zero under high offered loads means that the derivatives of other linear combinations of state probabilities, such as handoff dropping probability and new call blocking probability, will also converge to zero. Therefore, handoff dropping probability and new call blocking probability must be bounded by the logarithmic function of new call arrival rate for large arrival rates. Due to the feedback property embedded in the bandwidth reservation process, our admission algorithm offers QoS bounds both under nominal load and under high arrival rates. The analytical results have been validated by simulations.