Improved Frequency-Domain Equalization via Noise Whitening for Single-Carrier Underwater Acoustic Communications

Frequency-domain equalization (FDE) has been proved as an efficient equalization scheme for single-carrier underwater acoustic (UWA) communications, especially under benign channel conditions. In existing FDE designs, white noise assumption is generally adopted to simplify the implementation, even though actual noise in UWA communications is usually colored. Such a discrepancy incus potential performance loss. To address this issue, we propose an improved FDE scheme via noise whitening preprocessing. The whitening filter is designed through a factorization of estimated noise power spectrum. The improved FDE scheme has been verified by real data collected in an at-sea UWA communication experiment. It showed that, in light of noise whitening, extra performance gain was achieved for the improved FDE scheme as compared with a conventional scheme using white noise assumption.