Stochastic construction of optimal linear channel precoders for random channels

Abstract

Redundant linear precoders improve the reliability of digital communications over frequency selective fading channels by spreading the spectrum of each transmitted block, thus reducing the detrimental effects of channel spectral nulls. The design of optimal precoders under the simplifying assumption that the channel is known has already been studied in the literature. However, the design of optimal precoders for random (i.e., unknown) channels is an unresolved issue. This paper demonstrates that stochastic optimisation algorithms are a natural and effective solution to the optimal precoder design problem for random channels.