A non-data-aided SNR estimation algorithm for QAM signals

We propose a non-data-aided (NDA) signal-to-noise-ratio (SNR) estimation algorithm for quadrature amplitude modulation (QAM) signals in an additive white Gaussian noise (AWGN) channel. The NDA SNR estimation algorithm for QAM signals is derived based on a statistical ratio of observables over a block of data. The simple analysis and computer simulation for some kinds of QAM signals have been done, the results of which have proved that all the tested QAM signals can be effectively estimated by this algorithm.