Oversampling diversity for uncoded transmission of bandlimited sources over parallel fading channels

Uncoded transmission of a bandlimited signal over fading channels is considered. Each K signal samples are transmitted over N channels, thus increasing the sample numbers by a factor of N/K. The signals are pre-filtered to acquire certain statistical or spectral properties and then post-filtered at the receiver to obtain the best estimate. We incorporate the distortion outage probability as a benchmark to evaluate the quality of estimation. The main focus of this work is the scenario when the N fading channels are parallel, while the linear minimum mean square filter is used at the receiver. We show that the distortion outage probability vanishes inversely polynomially with SNR, with the exponent N − K + 1 for the high SNR regime, thus achieving a diversity order of N − K + 1 for the proposed oversampled uncoded transmission system.