SP-TPC: a self-protective energy efficient communication strategy for IEEE 802.11 WLANs

We propose a novel energy efficient communication strategy, called SP-TPC, for IEEE 802.11 wireless LANs (WLANs). SP-TPC utilizes both transmit power control (TPC) and PHY rate adaptation in order to minimize the communication energy consumption while maximizing the throughput performance. When TPC is employed in the 802.11 WLAN, the overall performance may be degraded due to the potential increase of hidden stations, and hence the request-to-send/clear-to-send (RTS/CTS) exchange is typically used in conjunction with TPC in order to eliminate hidden stations. However, the RTS/CTS exchange is an expensive solution since it itself consumes energy as well as precious bandwidth. By taking advantage of the existing clear channel assessment (CCA) mechanism intelligently, SP-TPC does not introduce any extra hidden stations, and hence RTS/CTS exchange is not needed if hidden stations did not exist without TPC. Through simulations, we demonstrate that SP-TPC outperforms other TPC strategies consistently in terms of both throughput and energy efficiency in small and mid-ranged WLAN environments.