On Achievable Data Rates and Optimal Power Allocation in Fading Channels with Imperfect Channel State Information

Abstract

Achievable rates of wireless communication systems with pilot-based channel estimation are investigated for the case of time-selective fading. Novel analytical expressions for the maximum achievable rates of such systems are derived in terms of the system signal-to-noise ratio (SNR), fading rate and estimation scheme deployed. The frame size is optimized jointly based on the SNR and the fading rate. The maximum rate achieving coding scheme is suggested and shown to be a modified version of the classical water-filling algorithm that accounts for imperfect channel state information (CSI) at the transmitter. The impact of the estimation scheme and the angular spread of the received signal on the quality of estimation and achievable rates is evaluated. A number of numerical simulations are provided to illustrate the dependence of the optimal block length and achievable rates on SNR, fading rate, estimation scheme and angular spread of the channel.

Effect of scattering environment on estimation quality in V2I and V2V communications

“…At the receiver vector y = [y [1] y [2]] is projected onto orthogonal columns of the channel matrix:…”

Light Wiener filters for estimation of slowly varying wireless channels

“…A channel estimation of high quality and efficiency is essential for the reliable performance of many diversity schemes. The most common approach is estimation via training sequences (pilots) which are periodically inserted into the data stream [1] - [4]. At the receiver side pilots are accumulated and used for calculation of channel gains via different pilot filters.…”