An Efficient Power-Saving MAC Protocol for MANETs with Multi-Channels

Power efficiency is one of the important considerations in mobile ad-hoc networks (MANETs). IEEE 802.11 features a power saving mechanism (PSM) in Distributed Coordination Function (DCF). At the start of each beacon interval, each node must stay awake for a fixed time, called an ATIM window. During the ATIM window, if the nodes do not have data to send or receive, they will enter the Doze state at the end of ATIM window. The size of the ATIM window has a significant impact on energy saving and throughput achieved by the nodes. Moreover, hosts of MANETs with PSM have larger end-to-end delays in delivering packets and suffer lower throughput than the standard IEEE802.11. Therefore, we propose an adapted power-saving MAC protocol, named APSMAC, to dynamically adjust the length of the ATIM window according to the network status. Furthermore, APSMAC use multiple channels to transmit data to enhance the throughput and reduce the collisions. We also designed a channel assignment scheme and two data transmission policies to enhance the performance of our protocol. The simulation results show that the proposed protocol reduces the delays and achieves higher throughputs and energy efficiencies on various traffic loads in MANETs.