Enhanced energy consumption reduction schemes in Radio-On-Demand WLANs

Current IEEE 802.11 wireless LAN (WLAN) rate adaptation schemes are intended to improve the communication efficiency by minimizing frame error rates, etc., and do not consider any energy efficiency of the WLAN at the same time. New WLAN developments, such as Radio-On-Demand (ROD), aim to reduce the energy consumption of WLAN access points (APs) during inactive periods, e.g., switching on/off the WLAN communication module. In order to further reduce the WLAN energy consumption, the design of adaptive controlling schemes is necessary which reduce the energy consumption while the AP is transmitting. In this paper, an enhanced energy consumption reduction scheme for ROD WLANs is proposed. The energy consumption of IEEE 802.11n WLAN module is analyzed for each modulation coding scheme (MCS). In addition, it is shown that the IEEE802.11n energy consumption can be approximated by our proposed analytical model. As a result, it was found that the number of multiple-input multiple-output (MIMO) radio frequency (RF) chains significantly affects the amount of energy consumption in WLAN APs. We then implement a simple RF chain control to our ROD WLAN AP prototype and show that the proposed scheme reduces the energy consumption of highspeed wireless LANs by 43% in the case of lower signal-to-noise ratio.