Saturation Performance of IEEE 802.11 Broadcast Scheme in Ad Hoc Wireless LANs

Abstract

Broadcast communication is important in inter- vehicle communication. Vehicles broadcast safety related messages to pre-warn the vicinity vehicles. The new IEEE 802.11p is being developed based on IEEE 802.11a to address the need for vehicle-to-vehicle and vehicle-to-roadside-unit communication. In this paper, we study the saturation performance of IEEE 802.11 broadcast by developing an analytic model as well as by conducting simulation. Having investigated the literature and studied the features of the broadcast, we point out that the analytic models for IEEE 802.11 unicast cannot be simply applied for broadcast. We construct our model to characterize the operation of the backoff counter in broadcast. Based on solutions to the model, closed form expressions of performance indices including throughput, packet delay, and packet deliver ratio are derived. Numerical results reveal several characteristics of the broadcast service. Our research work provides a new means to approach analysis and enhancement of IEEE 802.11 broadcast performance and reliability in wireless ad hoc networks.