Broadband FIR beamformer performance for underwater acoustic communication

Abstract

Beamforming for underwater acoustic communication (UAC) is affected by the broadband feature of UAC signal, which has relatively low center frequency compared to the signal bandwidth. In this paper, baseband equivalent array signal model for phase-coherent underwater acoustic communication is derived and we present computer simulation results for the broadband finite impulse response (FIR) beamformer performance according to the FIR filter order and the tap spacing. If the FIR filter order is increased above the optimum value, the beamformer performance is degraded. The inter-tap delay should be small enough and it is related to the optimum FIR filter order. The optimum length of FIR filter and the threshold of the tap spacing is dependent on the bandwidth to carrier frequency ratio (BCR).