Low-complexity Precoding for MIMO Channels with Finite Alphabet Input

What is it about?

This paper studies low-complexity precoding design without iteration for multiple-input multiple-output (MIMO) channels with finite alphabet input. Contrast to the iterative gradient method for finding the globally optimal precoder, which is time-consuming and computationally complicated, this work studies low-complexity precoding design with high-performance. We transform the problem of optimizing the mutual information into maximizing the minimum Euclidean distance of the input vector. Furthermore, we reveal that the precoding design can be formulated as semi-definite programming (SDP) problem and thus can be optimally solved. Numerical examples show that the proposed scheme achieves good tradeoff between the computational complexity and high performance compared to the conventional counterparts.

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