Orthogonal Frequency Division Multiplexing Spread Spectrum Underwater Acoustic Communication without Pilot Decision Feedback Channel Estimation Method under Sparse Channel Conditions

Abstract

The invention discloses a channel estimation method for orthogonal frequency division multiplexing spread spectrum underwater acoustic communication without pilot judgment feedback under sparse channel conditions, including: 1) OFDM frequency domain information extraction; 2) frequency domain extracted in step 1) The information is sent to the spread spectrum recognition module for spread spectrum recognition; 3) The result of step 2) spread spectrum recognition is sent to the decision feedback loop module to iteratively learn the underwater acoustic channel and rebuild the channel; 4) After equalizing the reconstructed channel The data despread output. The invention utilizes the sparse characteristic of the underwater acoustic channel to effectively identify the spread spectrum signal, and uses the identification result to perform judgment feedback estimation on the underwater acoustic channel response, thereby realizing reliable reconstruction of the underwater acoustic channel, and without losing communication quality , can reliably realize the equalization of the underwater acoustic communication signal, and effectively improve the underwater acoustic communication rate.

Description

technical field [0001] The present invention relates to the technical field of underwater acoustic communication and channel estimation. Aiming at the problem that the OFDM underwater acoustic communication technology needs to add pilot information for channel estimation to reduce the effective communication rate, a sparse channel is proposed. Orthogonal Frequency Division Multiplexing Spread Spectrum Underwater Acoustic Communication Without Pilot Decision Feedback Channel Estimation Method. This method uses the sparse characteristics of the underwater acoustic channel to effectively identify the spread spectrum signal, and uses the identification results to perform decision feedback estimation on the underwater acoustic channel response, so as to realize the reliable reconstruction of the underwater acoustic channel, and without loss of communication quality. , can reliably realize the equalization of the underwater acoustic communication signal, and effectively improve the ...

AI Technical Summary

Problems solved by technology

The methods proposed by the above several domestic and foreign researches preprocess the transmitted signals according to the channel conditions, thus avoiding the addition of pilot information during the communication process. However, this type of method needs to grasp the channel status before communication to conduct targeted Signal preprocessing, although it can reduce the complexity of signal processing at the receiving end, it will not improve the communication efficiency of the communication system, and has high requirements for channel stability, which is not suitable for the rapidly time-varying underwater acoustic channel environment

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