Enhancing Power Saving Mechanisms for Ad Hoc Networks Using Neighborhood Information

The power saving mechanism (PSM) was proposed by IEEE 802.11 for ad hoc networks in order to help prolong battery longevity for mobile nodes. A closer look at this mechanism enables us to see some room for further improvements of its performance especially for dense networks. According to the PSM, each station must announce its traffic before it can send it. Thus, PSM can require a large announcement period (the ATIM window) when there are many defined traffic flows so that all the stations can transmit their announcement frames. This paper contributes to the betterment of the PSM by proposing two new protocols (the BTA-PSM and the UTA- PSM), derived from the PSM. These protocols try to enhance its performance by inferring from the already advertised future behaviors of the neighboring nodes of a given mobile station. The proposed improvements aim at reducing the number of exchanged announcement frames in order to increase the throughput and decrease power consumption and delay. Simulations results testified to the superiority of the BTA-PSM and UTA-PSM schemes over the traditional PSM in ensuring greater power saving, higher throughput and lower delay.