Reflection-enabled directional MAC protocol for underwater sensor networks

Current medium access (MAC) protocols for underwater acoustic sensor networks (UW-ASNs) rely on omni-directional antennas as the basis for communication. The spatial inefficiency of such an antenna model limits the maximum achievable network throughput. This paper introduces a novel directional MAC protocol for UW-ASN that is based on a switch-beamed directional acoustic antenna and is not dependent on the line-of-sight (LOS). In the proposed reflection-enabled directional medium access (RED-MAC) protocol, each source node will be able to determine if an obstacle or another node is blocking the LOS link to the destination and switch to the best available directional antenna that will be reflected from the water surface or bottom. The destination will be able to determine if the received signal is the LOS or surface/bottom reflected by applying a homomorphic deconvolution process. The simulation results demonstrate the effectiveness of RED-MAC and the superiority of its performance in comparison to existing UW-ASN MAC protocols.