Table of contents
1. Theoretical basis
In digital communication systems, frequency offset is a common channel distortion that causes the received signal to shift in frequency, thereby affecting demodulation performance. Therefore, estimation and correction of frequency offset is a very important task in digital communication systems. Traditional frequency offset estimation methods usually use pilot sequences or synchronization words for frequency offset estimation, but these methods require a high signal-to-noise ratio, and the signal rate is relatively low. For signals with low signal-to-noise ratio and high rate, the effect of traditional frequency offset estimation methods is poor. The low SNR QAM signal frequency offset estimation method based on FFT transform is a new type of frequency offset estimation method. It does not need pilot sequence or synchronization word, but uses FFT transform to estimate frequency offset. This method is suitable for low signal-to-noise ratio and high-rate signals, with