A Framework for Power Management of Handheld Devices with Multiple Radios

The new generation of handheld devices is equipped with multi-radio interfaces that enable radio link connections to a variety of wireless networks (i.e. Wi-Fi, WiMAX).This allows for seamless connectivity; however, this also raises a serious issue concerning the short longevity of the handheld usability due to the high power consumption of the wireless interfaces. In this paper, we present a framework that increases considerably the battery longevity of the handheld devices; it enables efficient power management from a global point of view (and not a single radio interface view) of multi-radio devices. The basic idea behind our proposal is to power off the idle interface but at the same time to keep it in virtual idle mode in the network by extending IEEE 802.21 on both sides (the mobile node side and the network side). On the network side, the 802.21 entity acts as a proxy of the powered-off interface to insure the assigned resources for the interface are always maintained during the proxying period. In the context of the proposed framework, we present (details of) the mechanisms to proxy an idle interface (after powering it off) and to wake up a proxied interface respectively. The proposed solution is analytically evaluated to quantify the power savings compared with single-radio power management.