An energy-efficient interface selection for multi-mode terminals by utilizing out-of-band paging channels

With the advent of a number of wireless network technologies such as WCDMA and WLAN, current mobiles are equipped with multiple network interfaces, so called Multi-Mode Terminal (MMT). MMTs are capable to access different kinds of networks by performing a vertical handover between heterogeneous wireless networks, where during the idle state, the MMTs consume a lot of energy since their WLAN interface must wake up for listening to periodical beacons. However, previous studies on the vertical handover did not address how to select the optimal interface taking into account the characteristics of MMTs, especially energy consumption. Therefore, in this paper, we propose an energy-efficient interface selection scheme for MMTs in the integrated WLAN and cellular networks. The proposed interface selection scheme takes advantage of existing out-of-band paging channel of cellular networks, so that the WLAN interface can be completely turned off during the idle state leading to reduction in energy consumption. Simulation results show that the proposed scheme outperforms conventional approaches in terms of energy consumption with reduced signaling overhead and handover delay.