With the increase in the number of antennas at base stations (BSs), centralized multi-antenna architectures have encountered scalability problems from excessive interconnection bandwidth to the central processing unit (CPU), as well as increased processing complexity. Thus, research efforts have been directed towards finding decentralized receiver architectures where a part of the processing is performed at the antenna end (or close to it). A recent paper put forth an information-lossless trade-off between level of decentralization (inputs to CPU) and decentralized processing complexity (multiplications per antenna). This trade-off was obtained by studying a newly defined matrix decomposition--the WAX decomposition--which is directly related to the information-lossless processing that should to be applied in a general framework to exploit the trade-off. {The general framework consists of three stages: a set of decentralized filters, a linear combining module, and a processing matrix applied at the CPU; these three stages are linear transformations which can be identified with the three constituent matrices of the WAX decomposition. The previous work was unable to provide explicit constructions for linear combining modules which are valid for WAX decomposition, while it remarked the importance of these modules being sparse with 1s and 0s so they could be efficiently implemented using hardware accelerators.} In this work we present a number of constructions, as well as possible variations of them, for effectively defining linear combining modules which can be used in the WAX decomposition. Furthermore, we show how these structures facilitate decentralized calculation of the WAX decomposition for applying information-lossless processing in architectures with an arbitrary level of decentralization.

翻译：随着基站天线数量的增加，集中式多天线架构因中央处理单元（CPU）间互联带宽过大及处理复杂度提升而面临可扩展性问题。为此，研究重点转向探索去中心化接收机架构，即部分处理在端侧（或靠近端侧）完成。近期一篇论文提出了去中心化程度（CPU输入量）与去中心化处理复杂度（每根天线的乘法次数）之间的一种信息无损权衡。该权衡通过研究一种新定义的矩阵分解——WAX分解——得到，该分解与为利用此权衡而在通用框架中应用的信息无损处理直接相关。该通用框架包含三个阶段：一组去中心化滤波器、一个线性合并模块以及应用于CPU的处理矩阵；这三个阶段均为线性变换，可与WAX分解的三个组成矩阵对应。此前研究未能给出可用于WAX分解的线性合并模块的显式构造，同时指出这些模块应具有由1和0构成的稀疏性，以便利用硬件加速器高效实现的重要性。本文提出多种有效定义可用于WAX分解的线性合并模块的构造方案及其变体。此外，我们展示了这些结构如何促进WAX分解的去中心化计算，从而在任意去中心化程度的架构中应用信息无损处理。