EnRI-MAC: an enhanced receiver-initiated MAC protocol for various traffic types in wireless sensor networks

Energy consumption is the most significant factor determining the performance of wireless sensor networks. Most medium access control (MAC) protocols operate based on a duty-cycle mechanism to reduce idle listening time that contributes a significant portion of the sensor node battery depletion. Many conventional MAC protocols focus on enhancing the unicast traffic performance based on the duty-cycle; however, most of them have overlooked other traffic types. In this paper, we propose an enhanced receiver-initiated MAC (EnRI-MAC) protocol to support various traffic types in wireless sensor networks. The EnRI-MAC decreases two important contributors to energy depletion: duplicated transmission and retransmission. In the EnRI-MAC, the duplicated transmission decreases by assigning a rendezvous time for receiving broadcast and multicast data, and the retransmission is reduced by significantly decreasing the collision probability. We have verified the performance of the proposed EnRI-MAC in comparison with the RI-MAC using the ns-2 simulation. The simulation results indicate that the EnRI-MAC achieves improved broadcast and convergecast performance compared with that of the RI-MAC in terms of duty-cycle ratio and delivery latency, while maintaining identical unicast performance.