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

TL;DR

This paper derives a lower bound on the achievable data rate over noncoherent doubly selective Rician-fading channels with peak-power constraints, analyzing the effects of channel parameters and providing numerical results in underwater acoustic environments.

Contribution

It introduces a new lower bound on mutual information for noncoherent Rician channels considering peak-power constraints and channel memory, with explicit dependence on Doppler spectrum.

Findings

The lower bound accounts for channel uncertainty and peak-power limitations.

Channel delay and Doppler spread significantly impact the achievable rate.

Numerical results demonstrate the bound's applicability to underwater acoustic channels.

Abstract

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.