大规模离散MU-MIMO：低复杂度、信息理论最优检测与多用户码

摘要：研究了一种实际的大规模离散多用户多输入多输出（MU-MIMO）系统，涵盖了大规模天线与用户、实用的信道编译码、任意输入分布、仅接收机已知信道状态信息、一般右酉不变信道矩阵、模数转化器等实际通信约束。针对理想和低分辨率模数转换器下的大规模离散MU-MIMO系统，分别提出了低复杂度、信息理论最优接收机和多用户码设计准则，并给出实际多用户低密度奇偶校验码（LDPC）设计。数值实验证实所设计的多用户LDPC比现有的单用户LDPC获得了2～5 dB性能增益，同时还解决在信道恶劣和低分辨率模数转换器下单用户码无法准确恢复信息的难题，揭示了现有贝叶斯最优接收机与单用户码直接结合不再是最优方案。

关键词：大规模离散MU-MIMO；低复杂度；信息理论最优；迭代接收机；多用户码

Abstract: A practical massive discrete multi-user multiple-input multiple-output (MU-MIMO) system is studied, which includes massive antennas and users, practical channel coding and decoding, arbitrary input distributions, available channel state information at the receiver, general right-unitarily-invariant channel matrices, and the analog-to-digital converter. For massive discrete MU-MIMO systems with ideal and low-resolution analog-to-digital converters, the low-complexity and information-theoretically optimal receiver and multi-user code design principles are proposed, respectively, on which practical multi-user low-density parity-check codes (LDPC) are designed. Numerical results show that the designed multi-user LDPC can achieve a performance gain of up to 2~5 dB over the existing single-user LDPC. They also address the issue that single-user codes cannot successfully recover information under poor channel and low-resolution analog-to-digital converters, and reveal that the direct combinations of existing Bayes-optimal receivers with single-user codes are no longer optimal.

Keywords: Massive discrete MU-MIMO, low complexity, information-theoretically optimal, iterative receiver, multi-user code