Equal Gain Combining and Time-Reversal Precoding for Underwater Acoustic Communication

Interference that occurs in underwater acoustic channels is not only impulsive or narrowband, but also partial band interference that can damage the performance of the communication system. In underwater acoustic networks, many messages are lost due to partial band interference that damages different parts of the received signal depending on the relative position of the interferer, source of the information, and receiver. To overcome this problem, in this study, a combination of Time Reversal (TR) precoding and the equal gain combining (EGC) scheme is proposed. TR precoding is a proven effective way to overcome intersymbol interference (ISI) with its spatial and temporal focusing property, meanwhile the EGC scheme is considered to overcome the channel fading effect. TR-EGC combination proved to be superior by 4 dB compared to the conventional TR scheme at the BER value of 0,02. Besides, in this study, the theoretical expression of BER has generated from the combination of TR and EGC (TR-EGC) precoding.