Focusing on the problem that the routine decoding method cannot adapt to the changes of the acoustic channel and movements of sending and receiving nods in the pattern time delay shift coding underwater acoustic communication system
a dynamic adaptive decoding method is proposed. The method dynamically searches for every pattern code that carries with information using variable-length sliding window
real-timely corrects the deviation of the next code according to the decoding results and sends useful information as more as possible to copy correlator for decoding. The method is adaptable to the influence of received signals due to the movements of sending and receiving nods and changes of the acoustic channel
and greatly improves the performance of the system compared with the routine decoding method. Trials in Songhua Lake of Jilin province show that the bit error rate of the dynamic adaptive decoding method is zero when the communicating distance is 1 500 meters
and is less a tenfold than the routine decoding method when the communicating distance is 1 000 meters. The proposed method is simple
has strong adaptability
and gives a foundation for high-rate and robust underwater communication nets.
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