An Asynchronous Wakeup Power-Saving Protocol for Multi-Hop Ad Hoc Networks

Power-saving is a critical issue for all kinds of portable devices. The power-saving mode of IEEE 802.11 is designed for a single-hop (or fully connected) ad hoc network and is not applicable for multi-hop ad hoc networks. In this paper, we propose an asynchronous power-saving protocol for mobile ad hoc networks (MANETs) with unpredictable mobility and multi-hop communication. Neighbors that wish to communicate estimate the relative phase difference between their sleep/awake cycles. A station uses this phase information for transmitting the pending traffic. Stations can also increase their awake period for transmitting the data and to reduce latency for delay sensitive flows. Simulation studies indicate that the proposed asynchronous protocol is quite effective under various traffic characteristics and loads; energy saving can be as high as 70%, while the packet delivery ratio is comparable to networks without power management.