Design and analysis of linear precoders under a mean square error criterion, Part II: MMSE designs and conclusions

Abstract

Part I of this two-part paper formulated the precoder design problem as an optimisation problem and solved it with respect to a worst case criterion. Part II studies a similar optimisation problem but with respect to a criterion measuring average performance. A stochastic optimisation algorithm is proposed for solving this problem. For special cases, closed form solutions are also given. These results indicate linear precoders reduce the effects of frequency distortion caused by multipath channels but are powerless to counteract additive white Gaussian noise. The conclusion is linear precoders should introduce only a small amount of redundancy and be used in conjunction with an error correcting code capable of combatting additive noise.