An energy-efficient and receiver-driven MAC protocol for wireless sensor networks

This paper proposes an energy-efficient and receiver-driven, TDMA-based MAC protocol (RMAC) for wireless sensor networks. By placing the ownership of the timeslots in the hands of the receiver nodes and letting the receiver nodes assign the timeslots to their neighboring sender nodes, RMAC not only eliminates the need for the sender nodes to explicitly wake-up a receiver node for data transmission, but also eliminates any collision or contention overhead among the sender nodes. Our simulation results show that RMAC outperforms other sender-driven, TDMA-based MAC protocols in terms of the packet latency and power consumption. We also devised a mechanism to enable unused timeslots to be "stolen" by other sender nodes and show that in the case of uniform timeslots assignment among the sender nodes, "timeslots stealing" increases the network capacity by as much as 200%. In addition, we propose a simple timeslots reassignment procedure to allow the receiver nodes to redistribute the timeslots among the sender nodes according to their offered traffic load, and show that it enables the network to efficiently reduce the packet latency in the face of asymmetric, bursty traffic patterns.