Delay distribution and loss probability of bandwidth requests under truncated binary exponential backoff mechanism in IEEE 802.16e over Gilbert-Elliot error channel

Abstract

This paper presents the mathematical analysis of the truncated binary exponential backoff (TBEB) mechanism as a contentionresolution for bandwidth requests in the broadcast polling and themulticast polling in the IEEE 802.16e. We derive the delaydistribution and the loss probability of request packets in the TBEBover Gilbert-Elliot error channel, by analytic methods on theassumption of Bernoulli arrival process and the unsaturatedcondition. The optimal contention period of transmissionopportunities for transmitting bandwidth requests can be obtainedwhile satisfying QoS on delay bound and loss bound. Furthermore, wefind the utilization of transmission opportunity to see efficiencyof the bandwidth. Numerical examples show that the analyticalresults are well-matched with simulations, and the performanceevaluations in the broadcast polling and multicast polling arecompared on the mean delay, the loss probability and the utilizationof transmission opportunity. Numerical results address that themulticast polling with more groups has better performance than thebroadcast polling in the sense of shorter delay, lower lossprobability and higher utilization of transmission opportunity.