ELECTRONICS LETTERS, vol.40, no.11, pp.678-679, 2004 (SCI-Expanded)
A simple closed-form expression is derived for the low signal-to-noise ratio (SNR) asymptote of the Cramer-Rao bound (CRB) on the estimation of SNR for quarternary phase-shift-keying signals received over Nakagami-m fading channels with L branch equal gain diversity combining.