Adaptive transmission power control and rate selection scheme for maximizing energy efficiency of IEEE 802.11 stations

Energy efficiency in wireless communications is one of important research issues. Previous studies on reducing the energy consumption of IEEE 802.11 WLAN systems mainly focused on the energy consumption of a single-link transmission only. However, due to its carrier sensing property, all the WLAN stations in the network receive the transmitted frames. Hence, this single-link transmission not only consumes the energy of the transmitter and receiver of the link, but also consumes the energy of the other stations. Moreover, most of the previous work on energy efficiency optimization problems were considered in MAC perspectives. In this paper, we show that the energy efficiency of all the stations in WLAN network can be optimized by our proposed adaptive transmission power control and rate selection scheme, with more accurate analysis of the energy consumption in IEEE 802.11 MAC and IEEE 802.11n PHY. The proposed adaptive transmission power control and rate selection scheme achieves an increase in an average energy efficiency of 34% at the cost of 5% throughput degradation for 800bits payload size and 20 users, for varying the distance from 0m to 90m.