Energy efficiency and error resilience in coordinated and non-coordinated medium access control protocols

Energy efficiency of a MAC protocol is one of the most important performance metrics, especially in mobile ad hoc networks, where the energy sources are limited. Two key factors in achieving energy efficiency for a MAC protocol are coordination among the nodes and schedule-based channel access. In order to achieve a sufficient level of coordination among the nodes, and hence to achieve energy efficiency, the exchange of control information via control packets is vital. As such, coordinated MAC protocols, which regulate channel access through scheduling, have been shown to achieve very high energy efficiencies when compared to non-coordinated MAC protocols, which do not employ scheduling. However, due to their increased vulnerability to channel errors, the performance of coordinated MAC protocols is affected more by the channel bit error rate (BER) than non-coordinated MAC protocols, which lack such control packets. In this paper, we investigate the energy efficiency and resilience against channel errors for coordinated and non-coordinated MAC protocols. Our results reveal that it is possible to achieve better system performance with coordinated MAC protocols even in lossy channels, provided that the BER level is not extremely high.