An improved R-MAC based MAC protocol for underwater acoustic networks

Long propagation delay, limited bandwidth and high bit error rate pose great challenges in Media Access Control (MAC) protocol design for underwater acoustic networks. A reservation based MAC protocol called R-MAC designed for underwater acoustic networks was proposed and analyzed. However, there exists channel resources waste problem in R-MAC. In order to overcome this drawback, this paper proposes an improved R-MAC based MAC protocol for underwater acoustic networks, called NR-MAC. To improve the channel utilization, NR-MAC introduces a new control packet called xREV. Then a new mechanism for data sending and receiving is designed and improved scheduling algorithms at receiver are proposed. Simulation results show that NR-MAC increases the network throughput as compared with R-MAC.