Achievable Rates over Doubly Selective Rician-Fading Channels under Peak-Power Constraint

The goal of this paper is to obtain a better knowledge of the achievable data rate over noncoherent Rician fading channel with time and frequency memory. We assume that the average-power as well as the peak-power of the input signal are finite and the peak-power limitation is applied in the time domain. Expression for this rate is based on a lower bound on mutual information that assume independent and identically distributed input data symbols. The lower bound is expressed as a difference of two terms. The first term is the information rate of the coherent channel with a weighted signal-to-noise ratio that results from the peak-power limitation. The second term is a penalty term, explicit in the Doppler spectrum of the channel, that captures the effect of the channel uncertainty induced by the noncoherent setting. Impact of channel parameters, such as delay and Doppler spread, on the information rate are discussed and numerical applications on an experimental Rician channel surveyed in an acoustic underwater environment are also provided.