A robust receiver structure for time-varying, frequency-flat, Rayleigh fading channels

A receiver structure for unknown time-varying, frequency-flat, Rayleigh fading channels is proposed. Unlike the maximum-likelihood receiver structure, this receiver does not need any knowledge of the channel autocovariance or the received signal-to-noise ratio, and yet analytic and simulation results show that its bit-error rate performance is close to the optimal structure. The receiver is applicable to signals with constant or approximately constant envelopes or to linearly modulated signals using Nyquist pulses.