Patent ID: 8582634

Claim:
An OFDM signal demodulation method, comprising the following steps: adding a pre-obtained timing offset estimation value of an OFDM signal demodulation device to the initial position of an OFDM symbol of a received signal to obtain a window deviation value of the OFDM symbol; adding a channel time delay extension to the window deviation value to obtain a combined prefix initial position, calculating a combined OFDM signal value starting from the prefix initial position, and processing a Fast Fourier Transform (FFT) for the combined OFDM signal value to obtain a frequency domain data subcarrier signal; calculating a frequency domain original channel estimation value, processing channel estimation based on the original channel estimation value phase modification of the OFDM symbol according to a channel estimation compensation indication value, and processing equalization and detection for the frequency domain data subcarrier signal according to the channel estimation result, wherein calculating a frequency domain channel response of an OFDM synchronous symbol, and processing FFT for the frequency domain channel response to obtain a channel response on transform domain; dividing the channel response on transform domain into at least two segments and estimating the power of the signals in each segment, and then calculating the ratio between the signal power in each segment and a total power; comparing the ratios with a preset detection threshold in turn, and regarding the segment corresponding to the ratio as the channel time delay extension when a ratio is greater than the detection threshold.