1results about How to "Increase processing gain" patented technology

This invention discloses a signal receiving method for spread spectrum underwater acoustic communication in long-distance time-varying channels, comprising: acquiring the received communication signal, obtaining a baseband signal through down-conversion and low-pass filtering, and dividing the baseband signal into blocks according to pilot signals and spread spectrum sequence signals after synchronization; performing initial channel estimation using the pilot signals to obtain initial Doppler estimates, time delay estimates, and amplitude response estimates for each path; performing frequency offset compensation and resampling on the first spread spectrum sequence received signal using the estimated Doppler; constructing a Rake receiver for the first spread spectrum sequence signal to be estimated using the estimated time delay and amplitude response; combining the Rake receiver and using maximum likelihood estimation to realize the decision on the current spread spectrum sequence and the log-likelihood ratio of each corresponding bit; estimating the Doppler, time delay, and amplitude response of the current spread spectrum sequence signal using the decided spread spectrum sequence; and so on, completing the decision on all spread spectrum sequences. This invention can effectively reduce the demodulation bit error rate.