Demodulation Analysis Technique of OFDM Signal with Non-uniform CP Structure

This paper focuses on the analysis of demodulation of non-uniform cyclic prefix structure orthogonal frequency division multiplexing signals. Starting from the perspective of correcting the signal parameter structure, an algorithm based on each column rotation parameter backtracking the symbol position and fixing the parameter structure is proposed. The residual delay of the current symbol is derived by using the frequency offset contained in all estimated modulation index symbols. Then, the symbol starting position is corrected by interpolation, and the signal parameter structure is corrected based on the distance between adjacent symbol starting points. The simulation results show that the algorithm can control the demodulation bit error rate below 1% under the condition of a signal-to-noise ratio of not less than 5dB, and the results can continue to improve with changes in data volume and modulation method. Compared with existing frequency offset correction algorithms, the algorithm solves the essential problem of signal structure analysis and achieves a lower demodulation bit error rate and faster convergence in performance. The algorithm is highly robust and less affected by frequency offset, making it better suited for non-cooperative communication scenarios.