Design of Linear Precoders for Correlated Sources in MIMO Multiple Access Channels
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Date
2018
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Journal ISSN
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Publisher
IEEE
Abstract
This work focuses on distributed linear precod ing 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.