Mitigating the effect of multipath interference in shallow water acoustic channels

Non-stationary reflections from moving sea surface, along with unpredictable oceanographic phenomena such as surface wave focussing render multipath interference in shallow water acoustics difficult to model or track in real time. Traditional equalization techniques have met limited success in underwater acoustic communications due to these rapid channel fluctuations as well as time-varying sparsity of the multipath delay spread. In this work, we examine these key challenges in the context of shallow water acoustic channel equalization. Results are also presented based on experimental field data collected at 200 meters range, 15 meters depth and moderate to rough sea conditions.