Capacity-Achieving MIMO-NOMA: Iterative LMMSE Detection
Capacity-Achieving MIMO-NOMA: Iterative LMMSE Detection
复制标题
容量实现 MIMO-NOMA：迭代 LMMSE 检测
DOI：
10.1109/tsp.2019.2896242
复制
发表时间：
2019-04-01
影响因子：
5.4
通讯作者：
Li, Ying
中科院分区：
文献类型：
--
作者：
Liu, Lei;Chi, Yuhao;Li, Ying
针对多输入多输出非正交多址系统（MIMO-NOMA）中多个单天线用户同时与多天线基站（BS）通信的情况，研究了一种低复杂度迭代线性最小均方误差（LMMSE）多用户检测器。虽然LMMSE是一种线性检测器，复杂度较低，但由于LMMSE检测与多用户解码不匹配，在多用户检测场景下性能不理想。因此，在本文中，我们提供了MIMO-NOMA的检测器和解码器之间的匹配条件，然后利用这些条件推导出迭代检测的可实现率。证明了匹配迭代LMMSE检测器可以实现任意用户数下对称MIMO-NOMA系统的最优容量，任意用户数下非对称MIMO-NOMA系统的最优和容量，任意用户数下非对称MIMO-NOMA系统容量区内的所有极大极值点，以及两用户和三用户非对称MIMO-NOMA系统容量区内的所有点。此外，设计了一种实用的低复杂度纠错多用户码，称为不规则重复累积码，以匹配LMMSE检测器。数值结果表明，所提出的迭代LMMSE检测的误码率性能优于目前的方法，并且与相关容量限制的误差在0.8 dB以内。
This paper considers a low-complexity iterative linear minimum mean square error (LMMSE) multiuser detector for the multiple-input and multiple-output system with nonorthogonal multiple access (MIMO-NOMA), where multiple single-antenna users simultaneously communicate with a multiple-antenna base station (BS). While LMMSE being a linear detector has a low complexity, it has suboptimal performance in multiuser detection scenario due to the mismatch between LMMSE detection and multiuser decoding. Therefore, in this paper, we provide the matching conditions between the detector and decoders for MIMO-NOMA, which are then used to derive the achievable rate of the iterative detection. We prove that a matched iterative LMMSE detector can achieve the optimal capacity of symmetric MIMO-NOMA with any number of users, the optimal sum capacity of asymmetric MIMO-NOMA with any number of users, all the maximal extreme points in the capacity region of asymmetric MIMO-NOMA with any number of users, and all points in the capacity region of two-user and three-user asymmetric MIMO-NOMA systems. In addition, a kind of practical low-complexity error-correcting multiuser code, called irregular repeat-accumulate code, is designed to match the LMMSE detector. Numerical results shows that the bit error rate performance of the proposed iterative LMMSE detection outperforms the state-of-art methods and is within 0.8 dB from the associated capacity limit.