标题： 基于空间信息提取和波束选择的FDD下行链路大规模MIMO统计波束成形 显示英文标题

标题： Statistical Beamforming for FDD Downlink Massive MIMO via Spatial Information Extraction and Beam Selection

摘要： 在本文中，我们研究了频分双工（FDD）下行链路大规模MIMO系统中的波束成形设计问题，假设基站（BS）无法获得瞬时信道状态信息（CSI）。我们提出从上行链路信道估计过程中提取下行链路信道的到达角（AoDs）和相应的大尺度衰落系数（也称为空间信息）的信息，基于此提出了一种新的下行链路波束成形设计。通过根据空间信息和物理信道的隐藏稀疏性对不同用户的子路径进行分离，我们在波束成形设计中构建了近正交的虚拟信道。此外，我们推导了所提出系统的总速率表达式及其近似值。基于这些闭式速率表达式，我们开发了两种低复杂度的波束选择方案，并进行了渐近分析，以提供对系统设计的有价值见解。数值结果表明，我们的算法在性能上显著优于现有的波束成形方法。 显示英文摘要

摘要： In this paper, we study the beamforming design problem in frequency-division duplexing (FDD) downlink massive MIMO systems, where instantaneous channel state information (CSI) is assumed to be unavailable at the base station (BS). We propose to extract the information of the angle-of-departures (AoDs) and the corresponding large-scale fading coefficients (a.k.a. spatial information) of the downlink channel from the uplink channel estimation procedure, based on which a novel downlink beamforming design is presented. By separating the subpaths for different users based on the spatial information and the hidden sparsity of the physical channel, we construct near-orthogonal virtual channels in the beamforming design. Furthermore, we derive a sum-rate expression and its approximations for the proposed system. Based on these closed-form rate expressions, we develop two low-complexity beam selection schemes and carry out asymptotic analysis to provide valuable insights on the system design. Numerical results demonstrate a significant performance improvement of our proposed algorithm over the state-of-the-art beamforming approach.