Maximum likelihood estimation for SNR in Nakagami fading channels

The channel state information (CSI) estimation has become more and more important in various wireless communication systems. Signal-to-noise ratio (SNR) is a key part of CSI. The SNR estimation method requires high accuracy. In this paper, the new method of SNR estimation is proposed for PSK and QAM in Nakagami-m fading channels. The proposed method employs the maximum likelihood (ML) estimation based on the probability density function (pdf) of the received signal envelope. This estimation method is effective in unknown power condition without carrier synchronization. The numerical results show the proposed method works better than the moment-based method in high SNR.