Design of Linear Precoders for Correlated Sources in MIMO Multiple Access Channels

Author:

P. Suárez-Casal, J. P. González-Coma, O. Fresnedo, L. Castedo

Keyword:

Computer Science, Information Theory, Information Theory (cs.IT)

journal:

IEEE Transactions on Communications, vol. 66, n.o 12, pp. 6110-6122, Aug 2018

date:

2024-01-30 00:00:00

Abstract

This work focuses on distributed linear precoding when users transmit correlated information over a fading Multiple-Input and Multiple-Output Multiple Access Channel. Precoders are optimized in order to minimize the sum-Mean Square Error (MSE) between the source and the estimated symbols. When sources are correlated, minimizing the sum-MSE results in a non-convex optimization problem. Precoders for an arbitrary number of users and transmit and receive antennas are thus obtained via a projected steepest-descent algorithm and a low-complexity heuristic approach. For the more restrictive case of two single-antenna users, a closed-form expression for the minimum sum-MSE precoders is derived. Moreover, for the scenario with a single receive antenna and any number of users, a solution is obtained by means of a semidefinite relaxation. Finally, we also consider precoding schemes where the precoders are decomposed into complex scalars and unit norm vectors. Simulation results show a significant improvement when source correlation is exploited at precoding, especially for low SNRs and when the number of receive antennas is lower than the number of transmitting nodes.

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