Study on Channel Estimation Technique of OFDM Underwater Acoustic Communication System

The purpose of the underwater acoustic communication system lies in dependablely transmiting the signal from the source to the end through ocean acoustic channel at high speed.Orthogonal Frequency Division Multiplexing(OFDM) is a method that can combat multipaths,fully use the fequency band,has high data rate and has a promising future in UWA communication.While longer the transmission range,worse the underwater conditions with multipaths and Doppler offset,which needs to design the system parameters and take practical methods to improve the system.In this paper,we introduce basic algorithm for OFDM channel etimation basised on pilot,mainly study on algorithm of LS(Least-Square),LMMSE(Linear Minimum Mean Square Error),LRLMMSE(Low Rank Linear Minimum Mean Square Error) and analyse the performance and complexity of different algorithms.