A novel energy-efficient QoS-aware handover scheme over IEEE 802.11 WLANs

Energy efficiency in wireless networks is one of the major issues for mobile devices since they rely on their batteries. In this context, the wireless network interface card (WNIC) has to be taken into account carefully as it consumes a significant portion of the overall system energy. In this paper, we aim to reduce the energy consumption of mobile devices in wireless networks by performing specific solutions, such as reducing the overhead of the periodic background channel scanning, keeping mobile stations in the doze state as much as possible, proposing a smart selective channel scanning during the handover preparation phase and associating with an access point (AP) that is expected to consume the least energy among all APs. Stations performing the proposed scheme can fairly coexist with the other stations in the network. In the proposed scheme, each station makes use of its local information and the information provided by the IEEE 802.21 information server (IS). The proposed scheme can be easily implemented without any changes on the current IEEE 802.11 standard. Performance of the proposed scheme was investigated by numerical analyses and extensive simulations. The results illustrate that the proposed scheme is very efficient and reduces the energy consumptions of mobile stations under a wide range of contention and signal strength levels.