Energy-efficient scheduled directional medium access control protocol for wireless sensor networks

Directional antennas are known for spatial reuse, extended range, less interference, and less energy consumption as compared to omnidirectional antennas. In this paper, we propose an energy-efficient scheduled directional MAC (DTRAMA) algorithm for sensor networks, which is based on TRAMA with some modifications to exploit spatial reuse of directional antennas. In TRAMA, nodes achieve energy efficiency by following traffic-adaptive communication and sleep schedules. DTRAMA introduces spatial reuse checks in TRAMA to allow an otherwise sleep node to schedule transmission. Our simulation results show that DTRAMA is effective in exploiting spatial reuse of directional antennas by improving packet delivery ratio and packet delay of TRAMA. It, however, compromises energy efficiency by reducing average sleep time of a node.