Synchronization Method of Underwater Acoustic Communication Based on Zadoff-chu Sequence and OFDM Technology

Abstract

The invention provides an underwater acoustic communication synchronization method based on a Zadoff-Chu sequence and an OFDM technology. The method comprises the following steps of: generating to-be-transmitted signals through the OFDM technology, setting a length N of the Zadoff-Chu sequence to be the number of subchannels of OFDM; generating two segments of identical Zadoff-Chu sequences ZC-sq1 and ZC-sq2 with the length N by the same root sequence, adding the two segments of sequences to the front end of an OFDM signal, and adding one segment of protective interval with the length Ng between the two segments of sequences; respectively capturing the signal through two time windows of which the length is N, and judging whether a peak value greater than a threshold value Delta exists in correlation operation result; respectively locating the peak values greater than the threshold value Delta in the correlation operation result, taking a peak value position of which the peak value is greatest as the peak value position searched this time, respectively recording as N1 and N2; judging whether the distance between the N1 and the N2 is approximate to N+Ng; acquiring signals again and taking N2+Ng as a starting point of an OFDM signal data segment, and thereby completing synchronization. The underwater acoustic communication synchronization method provided by the invention improves precision, reliability and accuracy of synchronization.

Description

technical field [0001] The invention relates to the field of underwater acoustic communication synchronization, in particular to an underwater acoustic communication synchronization method based on Zadoff-Chu sequence and OFDM technology. Background technique [0002] OFDM technology has the advantages of anti-multipath, anti-interference, and effective anti-frequency selective fading, and has broad application prospects in shallow sea signal transmission scenarios. And because of its high channel utilization, this technology is more valuable in the marine environment with very limited spectrum resources. Like other underwater acoustic communication systems, communication methods based on OFDM technology rely heavily on synchronization means, and good synchronization is an important prerequisite for correct decoding at the receiving end of the system. Synchronization methods commonly used at this stage include linear frequency modulation synchronization methods, synchroniza...

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Problems solved by technology

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is the relatively high cross-correlation between the sync header signals, and it is possible to clearly distinguish the auto-correlation peak and the cross-correlation peak under the interference of noise

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