Practical Interference Exploitation Precoding without Symbol-by-Symbol Optimization: A Block-Level Approach

Fuente: arXiv
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Hauptverfasser: Li, Ang, Shen, Chao, Liao, Xuewen, Masouros, Christos, Swindlehurst, A. Lee
Format: Preprint
Veröffentlicht: 2022
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author Li, Ang
Shen, Chao
Liao, Xuewen
Masouros, Christos
Swindlehurst, A. Lee
author_facet Li, Ang
Shen, Chao
Liao, Xuewen
Masouros, Christos
Swindlehurst, A. Lee
contents In this paper, we propose a constructive interference (CI)-based block-level precoding (CI-BLP) approach for the downlink of a multi-user multiple-input single-output (MU-MISO) communication system. Contrary to existing CI precoding approaches which have to be designed on a symbol-by-symbol level, here a constant precoding matrix is applied to a block of symbol slots within a channel coherence interval, thus significantly reducing the computational costs over traditional CI-based symbol-level precoding (CI-SLP) as the CI-BLP optimization problem only needs to be solved once per block. For both PSK and QAM modulation, we formulate an optimization problem to maximize the minimum CI effect over the block subject to a block- rather than symbol-level power budget. We mathematically derive the optimal precoding matrix for CI-BLP as a function of the Lagrange multipliers in closed form. By formulating the dual problem, the original CI-BLP optimization problem is further shown to be equivalent to a quadratic programming (QP) optimization. Numerical results validate our derivations, and show that the proposed CI-BLP scheme achieves improved performance over the traditional CI-SLP method, thanks to the relaxed power constraint over the considered block of symbol slots.
format Preprint
id arxiv_https___arxiv_org_abs_2202_09830
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Practical Interference Exploitation Precoding without Symbol-by-Symbol Optimization: A Block-Level Approach
Li, Ang
Shen, Chao
Liao, Xuewen
Masouros, Christos
Swindlehurst, A. Lee
Information Theory
Signal Processing
In this paper, we propose a constructive interference (CI)-based block-level precoding (CI-BLP) approach for the downlink of a multi-user multiple-input single-output (MU-MISO) communication system. Contrary to existing CI precoding approaches which have to be designed on a symbol-by-symbol level, here a constant precoding matrix is applied to a block of symbol slots within a channel coherence interval, thus significantly reducing the computational costs over traditional CI-based symbol-level precoding (CI-SLP) as the CI-BLP optimization problem only needs to be solved once per block. For both PSK and QAM modulation, we formulate an optimization problem to maximize the minimum CI effect over the block subject to a block- rather than symbol-level power budget. We mathematically derive the optimal precoding matrix for CI-BLP as a function of the Lagrange multipliers in closed form. By formulating the dual problem, the original CI-BLP optimization problem is further shown to be equivalent to a quadratic programming (QP) optimization. Numerical results validate our derivations, and show that the proposed CI-BLP scheme achieves improved performance over the traditional CI-SLP method, thanks to the relaxed power constraint over the considered block of symbol slots.
title Practical Interference Exploitation Precoding without Symbol-by-Symbol Optimization: A Block-Level Approach
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2202.09830