Two-way turbo equalization method and system, underwater acoustic communication system

Abstract

The invention relates to a bidirectional turbo equalization method and system and an underwater acoustic communication system. The method comprises that a training sequence and a reception signal are obtained to carry out equalization, and equalization results are output; the equalization results are received, summarized in a weighted manner and then output; and the output value after weighted summation is decoded, and first and second output signals are output. The bidirectional turbo equalization method is high in stability and detection precision, rapid in convergence and low in complexity, and has certain application values and prospects in the practical underwater acoustic communication system.

Description

technical field [0001] The invention relates to the field of underwater acoustic communication, in particular to a two-way turbo equalization method and system, and an underwater acoustic communication system. Background technique [0002] Intersymbol interference caused by multipath effect in underwater acoustic communication is the main factor affecting the communication quality. Generally, an equalizer is used in a receiver to eliminate intersymbol interference, such as a maximum a posteriori (MAP) equalizer and a maximum likelihood sequence detection (MLSE) equalizer. However, these equalizers need to know the channel impulse response, and the computational complexity increases exponentially with the length of the channel impulse response, which is not suitable for practical use. Instead, there are some sub-optimal equalizers, such as least mean square (LMS) equalizer, recursive least squares (RLS) equalizer and decision feedback equalizer (DFE), etc. [0003] The turb...

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Problems solved by technology

[0006] (1) The two-way turbo equalization methods in the prior art are all based on channel estimation, and deconvolution is realized according to the estimated channel impulse response and the minimum mean square error (MMSE) algorithm, which involves multiplication of large-dimensional matrices And the inverse operation, the computational complexity is too high, which is not conducive to the real-time processing of data

[0007] (2) The turbo equalization method in the prior art relies too much on the accuracy of channel estimation, if the channel estimation is inaccurate, the equalizer and decoder will fail

Moreover, in a time-varying underwater acoustic channel environment, the channel impulse response estimated from the training sequence is difficult to represent the channel impulse response of effective data, which makes the equalization method in the prior art less stable

[0008] (3) The turbo equalization method in the prior art does not take advantage of the sparsity of the impulse response of the underwater acoustic channel, so that the redundancy of channel processing is too large, and the adaptive method in the prior art converges too slowly to make up for the timing Phase Error and Phase Distortion

These shortcomings will lead to the failure of the equalization process

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