A Novel Idle Mode Operation in IEEE 802.11 WLANs

While the IEEE 802.11 Wireless Local Area Network (WLAN) became a prevailing technology for the broadband wireless Internet access, new applications such as Internet Protocol (IP) telephony are fast emerging today. For the battery-powered IP phone devices, the standby time extension is a key concern for the market acceptance while today's 802.11 is not optimized for such an operation. In this paper, we propose a novel Idle Mode operation, which comprises paging, idle handoff, and delayed handoff. Under the idle mode operation, a Mobile Host (MH) does not need to perform a handoff within a predefined Paging Area (PA). Only when the MH enters a new PA, an idle handoff is performed with a minimum level of signaling. Due to the absence of such idle mode operation, both IP paging and Power Saving Mode (PSM) have been considered the alternatives so far even though they are not efficient. We develop a new analytical model to comparatively evaluate our proposed scheme. Our numerical results demonstrate that the proposed scheme outperforms the legacy alternatives with respect to power consumption, thus extending the standby time dramatically.