Performance enhancement in multihop wireless ad hoc networks

Poor bandwidth utilization of multihop ad hoc networks is a critical bottleneck that needs to be overcome before many interesting applications can be launched. In this paper we first propose a unified differentiation MAC architecture to support prioritized service. Based on the architecture we further propose a performance enhancement scheme for multihop wireless ad hoc networks. Unlike other schemes that may introduce extra overhead or may be incompatible with IEEE 802.11, our enhancement modifies the original IEEE 802.11 MAC and maintains the compatibility. By defining the interframe space and the contention window size as functions of the number of retransmissions, our enhanced scheme is able to give high priority to nodes which have retried many times to access the medium. As a result, it improves the overall performance in terms of end-to-end delay, packet deliver ratio, decreases the packet-dropping rate, and reduces the unnecessary routing discovery and update.