Channel reciprocity analysis for bi-directional shallow water acoustic communications

In underwater acoustic networks (UWANs) with bidirectional communication links, channel state information (CSI) plays an important role since having a good channel knowledge allows system performance enhancements. Two communicating nodes can use the information obtained by their respective channel estimation in order to adjust the transmission parameters to the channel characteristics. However forward channel estimation is generally different from the backward one. In this paper we investigate the acoustic channel reciprocity in a shallow water communication.