Real-Time Redundancy Allocation for Time-Varying Underwater Acoustic Channels

In this paper, the authors jointly address reliability and spectral efficiency in UnderWater Acoustic (UWA) communications by proposing optimal redundancy allocation over time-varying conditions in a communication link. To do so, they use recent results on tight approximation of codeword error probability in the finite block-length regime. First, they propose and evaluate an optimization framework. Then, they design a real-time algorithm, able to allocate the redundancy in a point-to-point link, without adding control messages. They evaluate the performance of the proposed algorithm by considering both rapidly and slowly time-varying experimental channel conditions.