IEEE logo

Coherence as a criterion for multichannel combining in low SNR communications in an upwelling environment

F. B. Louza and S.M. Jesus
LARSyS, University of Algarve, 8005-139 Faro, Portugal

Comments: download pdf (not available yet)
Ref.: OCEANS MTS/IEEE, Singapore (Malaysia), April 2020

Abstract: Establishing low signal-to-ratio (SNR) communications is a challenging task which aims at being undetected and may contribute to reduce underwater acoustic pollution minimizing impacts over marine life. In order to improve system reliability, the SNR at the receiver needs to be augmented, which is normally done by temporal and spatial coherent averaging. Much effort has been done to measure and understand coherence in shallow water [1,2]. However, in an upwelling shallow water environment, signals fluctuate rapidly with time due to short time scale oceanographic phenomena [3]. In the vicinity of busy harbors and areas of industrial construction, high noise levels may hamper efforts to recover acceptable SNR of weak communication signals. These factors influence the time of integration which is related to the effective bit rate of the communication system. The main goal of this study is to understand the impact of both temporal (TCOH) and spatial coherence (SCOH) over low SNR communications in a challenging channel and how to use coherence as a criterion to perform multichannel combination. Moreover, to compare results in terms of Bit Error Rate (BER) from data collected during the BioCom’19 experiment [4], using two independent arrays with four hydrophones each.

“©1992-2019 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for  advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”