An Adaptive Energy Efficient System within IEEE 802.11 Standard

Energy efficient wireless communication system is the key to the future. The goal of this paper is to maximize the energy efficiency performance of a wireless communication system within the IEEE 802.11 standards. The distributed coordination function (DCF) of IEEE 802.11 medium access control (MAC) provides two fundamental access modes, namely 2-way (basic access) and 4-way (RTS/CTS) frame exchange modes. We applied a fair 802.11h transmit power control (TPC) based power-rate adaptive scheme to both DCF access modes and propose a novel and effective strategy that allows any wireless stations to switch between the two access modes based on network conditions to achieve a truly energy efficient system. We analyze and compare the energy efficiency of 2-way and 4-way access modes with our proposed adaptive energy efficient scheme and our simulation results show that our proposed strategy gives a more superior performance in system energy utilization, by achieving an average of 20% Mbits/Joule gain compared to a rate-adaptive 2-way or 4-way DCF access mode for a ten-stations network.