Traffic Aware Power Saving Protocol in Multi-hop Mobile Ad-Hoc Networks

This paper presents an optimization of PSM to improve its energy conservation. According to PSM, time is divided into beacon intervals. At the beginning of each beacon interval, all stations must be awake during a specific period called ATIM window to be able to send and receive synchronization messages and announcements of buffered data frames. PSM specifies that a station having sent or received an announcement or having sent a beacon must remain awake during the entire beacon interval. This may lead to wasting energy specially at light traffic loads where stations should conserve the most. We propose an enhancement called the Traffic Aware Power Saving Mode (TA-PSM) to solve this problem by allowing nodes to enter the doze state when they are no more involved in data delivery even if they have already sent a beacon, an ATIM or an ATIM-ACK. Our objective is to reduce the energy consumption without any throttling to throughput. Extensive simulations based on fixed and dynamic topologies showed that TA-PSM provides a much better energy conservation and a lower power consumption per delivered data frame.