A novel cophasing method for reliable underwater acoustic communications

Small- and medium-range underwater acoustic communications have been received an increasing research interest due to its new and various applications such as underwater pollution monitoring, oceanographical data collection, scientific purpose, etc. Even though there has been much effort to enhance the quality of underwater communication, the study on underwater channel itself has not been investigated in detail. In this paper, we derive the condition which equates the phase of dominant interfering path to the phase of line-of-sight path and show that the detection performance of the cophasing could be improved considerably by finding out its upper and lower bounds.