A High Performance HF Orthogonal Spread Spectrum Iterative Demodulation and Decoding Method

Abstract

A high-performance short-wave orthogonal spread spectrum iterative demodulation and decoding method, including sampling the received signal at a chip rate after passing through a matched filter, correlating the sampled data with the local orthogonal spread spectrum sequence, and using the correlation value to perform non-coherent The demodulated output bit soft value; the bit soft value is used as the input of high-performance coding and decoding for iterative decoding; the decoding and decision output bits are used to reconstruct the orthogonal spread spectrum modulation signal, and realize the channel estimation of the path; the channel estimation restores the path Phase information, to achieve coherent demodulation of orthogonal spread spectrum; according to this process, iterative demodulation and decoding, until the iteration stops, output information bits. This method proposes the iterative demodulation and decoding structure of the orthogonal spread spectrum system; it improves the reliability of the demodulation bit soft value, and fully utilizes the performance of channel coding and decoding; at the same time, the iterative process further improves the accuracy of channel estimation, positive Cross-spread demodulation performance and decoding performance, thereby improving the transmission performance of the existing short-wave communication system.

Description

technical field

[0001] The invention relates to a reliable short-wave data communication transmission technology, in particular to a high-performance orthogonal spread spectrum iterative demodulation and decoding method. Background technique

[0002] The short-wave channel presents the characteristics of multipath fading, and the spread spectrum technology can effectively resist the influence of fading, and has certain anti-interference ability. Compared with direct sequence spread spectrum, multi-ary orthogonal spread spectrum can avoid the limitation of bandwidth on binary numbers, and can support high-ary numbers without additional insertion of cyclic prefix or training sequence, improving transmission efficiency, and according to digital communication theory, When the binary number of multi-ary orthogonal spread spectrum modulation tends to infinity, the performance close to Shannon's limit signal-to-noise ratio can be obtained. Therefore, multi-ary system orthogonal sp...

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