GANGs: an Energy Efficient Medium Access Protocol

Abstract

Recent advances in wireless communications and electronics have enabled the development of low-cost sensor networks. Low energy storage capacity is one of the critical features of nodes in these networks. Communication protocols at different layers have been proposed in order to reduce energy consumption. In this dissertation, existing work on energy efficiency is discussed. A new energy efficient MAC layer protocol, named GANGs is proposed. GANGs is a self-organized cluster-based hybrid MAC protocol. It incorporates both contention-free TDMA and contention-based IEEE 802.11 medium access schemes. The contention-free scheme is deployed by cluster head nodes to construct a contention-free network backbone. The contention-based scheme is deployed by ordinary nodes to communicate with cluster head nodes. This dissertation begins by discussing the existing work on throughput analysis through modeling IEEE 802.11 single hop networks under saturated traffic conditions, develops a mathematical model for the performance analysis of single-hop IEEE802.11 networks under unsaturated traffic, and then extends the model to 3 dimensions to analyze the performance of multi-hop IEEE 802.11 networks and networks using GANGs protocol. The performance metrics in the analysis cover not only throughput, but also message delay, queue length, packet drop rate, and energy consumption. With the new hybrid GANGs MAC protocol, data collisions for traffic forwarded from cluster to cluster will be eliminated, and thus a significant amount of energy is expected to be saved. The protocol will then be implemented and evaluated through simulation.