Neighborhood aware power saving mechanisms for ad hoc networks

Abstract

Due to their mobility, stations in ad hoc networks are equipped with autonomous batteries providing limited resources of energy. Thus power conservation proves to be a paramount factor to increase the network lifespan. A closer look at the mechanism of IEEE 802.11 PSM and all its numerous derivative proposals enables us to see some room for further improvements especially for large and dense cluster based networks. This paper presents an optimization of the functional properties of PSM to improve its energy conservation without changing or requiring additional control or management frames, yet it contributes to the betterment of all PSM derivatives especially for those based on a dynamic announcement window such as the Dynamic Carrier Sense DCS-PSM. PSM specifies that a station must announce its traffic before. The announcement traffic puts a heavy constraint on the size of both the ATIM period and the beacon interval and consequently on throughput, end to end delay and power saving. The proposed Neighborhood Aware Power Saving Mechanisms (NA-PSM and NTA-PSM) aim at reducing the number of exchanged announcement frames in order to increase the throughput and decrease both power consumption and delay. Simulation results testified to the superiority of NTA-PSM over PSM and the Dynamic Carrier Sense PSM (DCS-PSM) in ensuring greater power saving, higher throughput and lower delay.