3 results about "Gold code" patented technology

The invention particularly relates to a method for converting pseudo code capture into tracking phase compensation under clock frequency offset. The method comprises the steps of band-pass sampling and digital down-conversion, local pseudo code sequence generation, twice pseudo code capture and phase compensation. Selecting a sampling frequency and processing a signal through a band-pass sampling theorem, and generating a local pseudo code based on a Gold code; a PMF-FFT method of a mobile pseudo code is adopted to complete first-time pseudo code capture, a multiplexing capture module executes second-time full-range capture, and pseudo code phase offset is accurately calculated; and finally, adjusting the local pseudo code phase through the total phase compensation value, so that the phase difference between the input signal and the local pseudo code is controlled within a half chip. According to the method, hardware cost does not need to be increased, the problem of inaccurate phase compensation under clock frequency offset, large frequency offset and low carrier-to-noise ratio scenes is effectively solved, it is guaranteed that pseudo code capture is smoothly converted into tracking, and the tracking reliability of a receiver is improved.

This application relates to a multi-channel parallel Doppler estimation method for shallow water acoustic communication systems, comprising: a transmitting end converting the signal to be transmitted into binary code, framing it according to a preset QPSK signal frame format, and transmitting the QPSK signal, wherein the QPSK signal uses Gold code as the frame header; a data receiving step, wherein the QPSK signal is transmitted to the receiving end via an underwater acoustic channel, and the receiving end acquires the received signal; and a Doppler estimation step, wherein the received signal is converted from analog to digital by an analog-to-digital converter to obtain a discrete sequence of the received signal, the discrete sequence is input into multiple Doppler channels, and Doppler estimation is performed in parallel based on N Doppler channels to obtain multiple output values, and a correlation detection module is used to determine the estimated Doppler factor value from the multiple output values. This application improves the accuracy of Doppler estimation in shallow water acoustic communication through a multi-channel parallel approach.

This invention relates to the field of wireless communication technology, specifically disclosing a soft-decision method for GFSK signals based on multi-sampling point adaptive weighting. The method includes: extracting phase change features from the I / Q signal and performing three-level anti-interference processing to obtain an optimized phase difference sequence; performing frequency offset correction and symbol synchronization on the optimized phase difference sequence based on a predefined local ZC preamble sequence and a local gold code sequence in the frame structure; selecting three sampling points (middle, left, and right) from eight times the oversampling points in each symbol period; performing interference compensation on the data from the three sampling points and then weighting and fusing them to obtain a weighted fused sequence; constructing a reference sequence based on the local gold code sequence, and calculating the log-likelihood ratio between the reference sequence and the weighted fused sequence bit by bit as the soft decision value; and performing subsequent decoding based on the soft decision value. This invention can stably reduce the bit error rate and maximize the system coding gain in low signal-to-noise ratio and multipath interference scenarios.