3 results about "Rake receiver" patented technology

The application discloses a signal receiving method for spread spectrum underwater acoustic communication of long-distance time-varying channel, which comprises the following steps: obtaining the received communication signal, carrying out down-conversion and low-pass filtering to obtain a baseband signal, and carrying out synchronization to divide the baseband signal into pilot signals and spread spectrum sequence signals; using the pilot signals to complete initial channel estimation to obtain initial Doppler estimation value, time delay and amplitude response estimation value of each path; using the estimated Doppler to carry out frequency offset compensation and resampling on the first spread spectrum sequence receiving signal; using the estimated time delay and amplitude response to construct a first to-be-estimated spread spectrum sequence signal Rake receiver; combining the Rake receiver and using maximum likelihood estimation to realize the decision of the current spread spectrum sequence and the log-likelihood ratio of each bit; using the decided spread spectrum sequence to estimate the Doppler, time delay and amplitude response of the current spread spectrum sequence signal; and in this way, the decision of all spread spectrum sequences is completed. The application can effectively reduce the demodulation error rate.

A method for dynamically adjusting the revisit rate of a rake receiver for an individual UE is disclosed, such that the time to initially acquire the UL transmission is optimized while the ongoing Central Processing Unit (CPU) loading during normal operation is minimized. The method may comprise operating a multipath searcher in a first mode of operation at a first time, the first mode being an acquisition mode, the multipath searcher operating with a revisit rate of 100 percent; and, operating the multipath searcher in a second mode of operation at a second time, the second mode being a steady-state mode and the multipath searcher operating with a revisit rate of less than 100 percent.

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.