A Parallel Decoding Approach for Mitigating Near-Far Problems in Underwater Acoustic Communications Networks

Abstract—A limiting factor of communication networks is the so-called near-far effect, where transmissions from a node (near) close to a common receiver blocks transmissions of a farther node (far). Due to the high power attenuation in the underwater acoustic channel, near-far is common in underwater acoustic communication networks (UWANs), and the phenomena occurs even for a rate of 1/2 between the distances of the near and far nodes to the receiver. In this paper, we offer a novel interference cancellation (IC) approach for handling such interference by decoding the ”near” signal and the ”far” one in parallel, thereby improving detection for both signals. Simulation results show that, compared to the traditional decision feedback equalizer, our approach gains 12 dB in the output SNR of the jammed source and 4 dB in the output SNR of the jamming source.
Index Terms—Underwater acoustic communications, near-far, interference cancellation, compresive sensing