Research On SNR Estimation Methods For OFDM Systems

Many communication technologies such as adaptive modulation technology, power control, diversity reception and so on, adjust their signal parameters or processing methods according to the SNR so as to maximize the frequency efficiency. SNR estimation technique is an important research issue in communication systems. The paper mainly deals with the problem of SNR estimation in OFDMcommunications systems. Firstly, the time-frequency autocorrelation characteristics of the wireless channels are analyzed in detail. Then the time autocorrelation coefficients and frequency autocorrelation coefficients of the wireless channels are obtained. Secondly, the SNR estimation algorithms of OFDM systems are discussed in the AWGN channels and wireless channels respectively. According to the characteristics of the wireless channels with the exponential decay delay profile, a novel SNR estimation algorithm is proposed based on the frequency autocorrelation coefficients of the wireless channels. It is easy to implement with low complexity, but its shortcoming is that it can only be applied to the channels with the exponential decay delay profile. Lastly, we make an extension, and thus obtain an SNR estimation algorithm which is suitable for any channel.