WSF-MAC: A weight-based spatially fair MAC protocol for underwater sensor networks

The high propagation delay in Underwater Sensor Networks (UWSNs) causes space-time uncertainty, making spatial fairness a challenging problem in UWSNs. In this paper, we propose a weight-based spatially fair MAC protocol (WSF-MAC) for UWSNs. It postpones sending the underwater-reply (UW-REP) packet for a silence duration time, and then determines the node to send UW-REQ first according to the sending time and competition count of the underwater-request (UW-REQ) packets and send UW-REP to get ready for transmission. The simulation results show that WSF-MAC can achieve a better performance in terms of the spatial fairness by about 10%.