Quantization and Feedback of Spatial Covariance Matrix for Massive MIMO Systems With Cascaded Precoding
Quantization and Feedback of Spatial Covariance Matrix for Massive MIMO Systems With Cascaded Precoding
复制标题
级联预编码大规模 MIMO 系统空间协方差矩阵的量化和反馈
DOI：
10.1109/tcomm.2017.2658619
复制
发表时间：
2017
影响因子：
8.3
通讯作者：
Han Wei
中科院分区：
文献类型：
--
作者：
Liu Yinsheng;Li Geoffrey Ye;Han Wei
本文研究了级联预编码的大规模多输入多输出（MIMO）系统下行链路空间协方差矩阵的量化和反馈问题。大规模MIMO技术由于能够显著提高网络性能而受到广泛关注。为了减少频分双工大规模MIMO系统中下行链路信道估计和上行链路反馈的开销，级联预编码被用于将高维物理信道转换为低维有效信道。对于级联预编码，内部预编码器由下行链路空间协方差矩阵确定，其在基站（BS）中是未知的。为了解决这个问题，我们提出了一个基于空间谱的方法的量化和空间协方差矩阵的反馈。以这种方式，BS可以获得关于下行链路空间协方差矩阵的部分信息。我们的结果表明，内部预编码器的基础上提出的方法可以被看作是调制离散长椭球序列，从而实现更小的空间泄漏比传统的离散傅里叶变换子矩阵为基础的预编码。本文还讨论了所提出的方法的应用的实际问题。
In this paper, we investigate the quantization and the feedback of downlink spatial covariance matrix for massive multiple-input multiple-output (MIMO) systems with cascaded precoding. Massive MIMO has gained a lot of attention recently because of its ability to significantly improve the network performance. To reduce the overhead of downlink channel estimation and uplink feedback in frequency-division duplex massive MIMO systems, cascaded precoding has been used to convert high-dimensional physical channels into low-dimensional effective channels. For the cascaded precoding, the inner precoder is determined by the downlink spatial covariance matrix, which is unknown in the base station (BS). To address this issue, we propose a spatial spectrum-based approach for the quantization and the feedback of the spatial covariance matrix. In this manner, the BS can obtain partial information on the downlink spatial covariance matrix. Our result shows that the inner precoder based on the proposed approach can be viewed as modulated discrete prolate spheroidal sequences and thus achieves much smaller spatial leakage than the traditional discrete Fourier transform submatrix-based precoding. Practical issues for the application of the proposed approach are also addressed in this paper.