Analysis of Underwater Acoustic Communication System Using Equalization Technique for ISI Reduction

Abstract Underwater Acoustic Communication (UWAC) has been an active research area over a decade. Apart from regular communication inside the water, the applications include Remotely Operated Vehicles (ROV), Underwater Sensor Networks (UWSN), military and navigation applications, diving purposes, Autonomous Underwater Vehicles (AUV), underwater sports, etc. The major disadvantages of UWAC are frequency-dependent attenuation, short range of communication, very low bandwidth. In this paper, Modulation techniques such as BPSK, QPSK, and 4-QAM are used in UWAC in order to reach longer distances inside water. The fundamental key aspect of UWAC including significant multipath interference and strong ambient noise, are addressed. Equalization techniques are used at the receiver to overcome the Inter symbol Interference (ISI) caused due to multipath propagation. Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) equalizers are used in this paper. However, ZF comes at the cost of increasing the noise; however; MMSE reduces all the noise levels in UWAC.