Impact of imperfect channel state information upon the outage capacity of Rayleigh fading channels

The outage capacity of a Rayleigh flat fading channel completely unknown at the transmitter and partially known at the receiver is considered in this paper. Analytical expressions for the upper and lower bounds of the outage capacity of such channels are obtained as a function of the channel estimation error at the receiver. Those results reveal how the noise level and the channel uncertainty combine in reducing the outage capacity of the fading channel. In addition, by deriving an expression for the estimation error variance of pilot symbol assisted modulation (PSAM), we are able to establish direct relations among estimation parameters, channel characteristics (in terms of SNR and normalized Doppler spread) and its impact on the outage capacity.