Orthogonal frequency division multiplexing spread spectrum underwater acoustic communication pilot-free decision feedback channel estimation method under sparse channel condition

Abstract

The invention discloses an orthogonal frequency division multiplexing spread spectrum underwater acoustic communication pilot-free decision feedback channel estimation method under the sparse channel condition. The method comprises the steps that 1) OFDM frequency domain information extraction is performed; 2) the extracted frequency domain information in the step 1) is transmitted to a spread spectrum identification module to perform spread spectrum identification; 3) the spread spectrum identification result of the step 2) is transmitted to a decision feedback loop module, iterative learning of an underwater acoustic communication is performed and the channel is reconstructed; and 4) despreading outputting of the data balanced by using the reconstructed channel is performed. The spread spectrum signal is effectively identified by using the sparse characteristic of the underwater acoustic communication channel, and decision feedback estimation is performed on the underwater acoustic communication channel response by using the identification result so that reliable reconstruction of the underwater acoustic communication channel can be realized, balancing of the underwater acoustic communication signal can be reliably realized without loss of the communication quality and the underwater acoustic communication rate can be effectively enhanced.

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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