SNR estimation for OFDM signals in frequency selective fading channels

Owing to the frequency-selective fading channel with a carrier frequency of OFDM (orthogonal frequency division multiplexing) signal to noise ratio (SNR) estimation problem, we proposed SNR blind estimation method based on air carrier OFDM system. Due to the inconsistency between the oscillator and the received signal, the received signal will be with a certain deviation. The presence of frequency offset destroyed the orthogonality among subcarriers and increased the interference noise, and then reduced the SNR. This paper analyzed the effects of frequency offset on the signal to noise ratio, followed by characteristics of air carrier to estimate the SNR where there is no frequency offset, and then based on the above premise to estimate SNR where the signal has the frequency offset. Finally, this paper proved the correctness of theoretical analysis by simulation.