Channel Equalization Algorithm Based on Wavelet De-Noising and Decision Feedback in Underwater Acoustic OFDM System

Noise in water is very crtical and may destroy the the OFDM based underwater acoustic communication system. The performance of pilot tones based channel estimation will not be the good choice under low SNRs. Complete frequency response of data channel is usually obtained by interpolating channel frequency response at pilot bits, such that the error of interpolation influences and degrades the performance of channel equalization. In this paper, we propose a method of channel equalization, which is based on wavelet de-noising and decision feedback. The results of channel estimation is accomplished through wavelet de-noising, the gain of entire channel frequency response by transform domain interpolation, and subsequent step of decision feedback equalization. The proposed method can restrain the interference of noise and interpolation error effectively and can also improve the system performance. Simulation and field experimental results also explained the promosing performance of this scheme.