Block-Level Interference Exploitation Precoding without Symbol-by-Symbol Optimization
Block-Level Interference Exploitation Precoding without Symbol-by-Symbol Optimization
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DOI：
10.1109/wcnc55385.2023.10118875
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
Ang Li;Chao Shen;Xuewen Liao;C. Masouros;A. L. Swindlehurst
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作者：
Ang Li;Chao Shen;Xuewen Liao;C. Masouros;A. L. Swindlehurst
基于构造性干扰(CI)概念的符号级预编码(SLP)优于传统的块级预编码(BLP)，但在预编码设计过程中以逐符号优化为代价。提出了一种用于多用户多输入单输出(MU-MISO)通信系统下行链路传输的基于CI的块级预编码(CI-BLP)方案，该方案为一组符号时隙设计了一个恒定的预编码矩阵，以同时利用每个符号时隙的CI。由于优化问题在每个块上只需求解一次，因此提出了在整个块上最大化最小CI效应的单个优化问题，从而降低了传统SLP的计算成本。通过利用Karush-Kuhn-Tucker(KKT)条件和对偶问题的表述，最终证明了原始优化问题等价于单纯形上的二次规划(QP)。数值结果验证了我们的推导，并且由于放宽了块级功率限制，所提出的CI-BLP方案的性能优于传统的BLP和SLP方案。
Symbol-level precoding (SLP) based on the concept of constructive interference (CI) is shown to be superior to traditional block-level precoding (BLP), however at the cost of a symbol-by-symbol optimization during the precoding design. In this paper, we propose a CI-based block-level precoding (CI-BLP) scheme for the downlink transmission of a multi-user multiple-input single-output (MU-MISO) communication system, where we design a constant precoding matrix to a block of symbol slots to exploit CI for each symbol slot simultaneously. A single optimization problem is formulated to maximize the minimum CI effect over the entire block, thus reducing the computational cost of traditional SLP as the optimization problem only needs to be solved once per block. By leveraging the Karush-Kuhn-Tucker (KKT) conditions and the dual problem formulation, the original optimization problem is finally shown to be equivalent to a quadratic programming (QP) over a simplex. Numerical results validate our derivations and exhibit superior performance for the proposed CI-BLP scheme over traditional BLP and SLP methods, thanks to the relaxed block-level power constraint.