Maximum likelihood estimation of SNR using digitally modulated signals

The problem of estimating two measures of signal-to-noise ratio (SNR) is investigated, both for static and slowly fading channels without memory. Maximum likelihood SNR estimators that use digitally modulated signals are derived for sampled signal processing receivers as well as continuous time signal processing receivers. The performances of the estimators are examined analytically in terms of biases and root-mean-squared errors. Numerical results are presented to show their good performances