论文标题
毫米波大量的MIMO系统具有量化相位变速器的两步代码字设计
Two-Step Codeword Design for Millimeter Wave Massive MIMO Systems with Quantized Phase Shifters
论文作者
论文摘要
在本文中，提出了一种毫米波（MMWave）的两步代码字设计方法。理想的代码字是首先设计的，它忽略了相移分辨率和RF链数方面的硬件约束。基于理想的代码字，然后将实用的代码字考虑到硬件约束。对于第一步中理想的代码字设计，将额外的阶段引入梁增益以提供额外的自由度。我们开发了一种相移的理想代码字设计（PS-ICD）方法，该方法基于替代最小化，每次迭代都具有封闭形式的解决方案，并且可以扩展到具有不同光束图案的更通用的光束成形向量。一旦在第一步中获得理想的代码字，第二步中实用的代码字设计问题就是通过相位变速器分辨率和RF链的数量来考虑混合预码结构的硬件约束来接近理想的代码字。我们提出了一种基于快速搜索的替代最小化（FS-ALTMIN）算法，该算法或设计模拟预编码器和数字预编码器。仿真结果验证了所提出的方法的有效性，并表明基于两步方法设计的代码字优于现有方法设计的代码。
In this paper, a two-step codeword design approach for millimeter wave (mmWave) massive MIMO systems is presented. Ideal codewords are first designed, which ignores the hardware constraints in terms of phase shifter resolution and the number of RF chains. Based on the ideal codewords, practical codewords are then obtained taking the hardware constraints into consideration. For the ideal codeword design in the first step, additional phase is introduced to the beam gain to provide extra degree of freedom. We develop a phase-shifted ideal codeword design (PS-ICD) method, which is based on alternative minimization with each iteration having a closed-form solution and can be extended to design more general beamforming vectors with different beam patterns. Once the ideal codewords are obtained in the first step, the practical codeword design problem in the second step is to approach the ideal codewords by considering the hardware constraints of the hybrid precoding structure in terms of phase shifter resolution and the number of RF chains. We propose a fast search based alternative minimization (FS-AltMin) algorithm that alternatively designs the analog precoder and digital precoder. Simulation results verify the effectiveness of the proposed methods and show that the codewords designed based on the two-step approach outperform those designed by the existing approaches.
