An energy-efficient QoS-based network selection scheme over heterogeneous WLAN - 3G networks

Energy efficiency in wireless networks is one of the major issues for users as mobile devices rely on their batteries. In this context, Wireless Network Interface Cards (WNICs) have to be taken into consideration carefully as it consumes a significant portion of the overall system energy. In this paper, we aim to reduce the energy consumption of wireless mobile devices performing specific solutions, such as reducing the overhead of channel scanning by proposing a smart selective channel scanning method during the handover preparation phase and associating with a Point of Attachment (PoA) that is expected to consume the least amount of energy among all PoAs. Power consumption prediction of a station is made by using the channel scanning results, switching costs, Channel Busy Times (CBTs), traffic class of the station, the number of stations deployed in each PoA, and the power consumption of each WNIC. 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 Media Independent Handover (MIH) Information Server (IS). Performance of the proposed scheme has been investigated by numerical analyses and extensive simulations. The results illustrate that the proposed scheme reduces the energy consumption of mobile stations and provides longer lifetime under a wide range of contention and signal strength levels.