An adaptive logical link layer protocol for Underwater Acoustic Communication channels

Underwater Acoustic Communication (UAC) is characterized by long propagation delays and very noisy channels. Further, both the signal propagation speed and the channel bit error rate are not constant but rather change dynamically depending on the depth and salinity of the water, the activity in the water´s surface, the topography of the bottom, and many others factors. This paper builds upon our previous work on logical link control protocols for underwater communications improving the performance of the SW-MER protocol by making it adaptive to channel conditions. In the proposed adaptive version, the protocol exchanges channel quality information to change the number of retransmitted copies, improving the throughput without compromising the reliability of SW-MER. Our simulation experiments with Bernoulli errors and synthetic traces demonstrate that the throughput can be improved in as much as 15% compared with the non-adaptive original version.