Cramer-Rao Bound for NDA SNR Estimates of Square QAM Modulated Signals
Faouzi Bellili, Alex Stéphenne, Sofiène Affes · 2009
In this paper, we derive analytical expressions for the inphase/quadrature Cramer-Rao lower bounds (I/Q CRLB) for the non-data-aided (NDA) signal-to-noise ratio (SNR) estimation of square quadrature amplitude modulated (QAM) signals. The channel is supposed to be slowly time-varying so that it can be assumed constant over the observation interval. The signal is assumed to be corrupted by additive white Gaussian noise (AWGN). We will demonstrate that the shape of the bounds differs greatly as the modulation order changes.