Effect of Underwater Ambient Noise on Quadraphase Phase-shift Keying Acoustic Sensor Network Links in Extremely Low Frequency Band

Abstract

This study evaluates the impact of underwater ambient noise using seven real noise samples; Dolphin, Rain, Ferry, Sonar, Bubbles, Lightning, and Outboard Motor in three frequency ranges in extremely low frequency (ELF) band. The ELF band is the most significant bandwidth for underwater long-range communication. ELF band which is extended from 3 to 3000 Hz clearly, faces bandwidth limitation. Measuring the impact of noises that are imposed on this bandwidth, based on center frequency employment is highly regarded. This measurement optimizes detection process and assists the design of more reliable underwater communication systems and will improve network quality of service (QoS). In this investigation, Quadraphase Phase-shift Keying (QPSK) acoustic communication nodes are designed in MATLAB and real noise samples are added to network link. Three frequency bands are defined (0-1600), (400-2000) and (1600-3200) Hz, then the impact of noise samples on phase is measured. Next, ( ) ratio for every bandwidth (BW) is simulated. The result demonstrates 0 to 1600 Hz band is the nosiest part of the ELF band. This study discovered the Bubble noise sample from the environmental noise; Ferry from man-made noise and the Dolphin in mammal’s noise have the greatest impact on 0 to 1600 Hz bandwidth.