Signal detection in large multiple-input multiple-output (large-MIMO) systems presents greater challenges compared to conventional massive-MIMO for two primary reasons. First, large-MIMO systems lack favorable propagation conditions as they do not require a substantially greater number of service antennas relative to user antennas. Second, the wireless channel may exhibit spatial non-stationarity when an extremely large aperture array (ELAA) is deployed in a large-MIMO system. In this paper, we propose a scalable iterative large-MIMO detector named ANPID, which simultaneously delivers 1) close to maximum-likelihood detection performance, 2) low computational-complexity (i.e., square-order of transmit antennas), 3) fast convergence, and 4) robustness to the spatial non-stationarity in ELAA channels. ANPID incorporates a damping demodulation step into stationary iterative (SI) methods and alternates between two distinct demodulated SI methods. Simulation results demonstrate that ANPID fulfills all the four features concurrently and outperforms existing low-complexity MIMO detectors, especially in highly-loaded large MIMO systems.

翻译：大规模多输入多输出（large-MIMO）系统中的信号检测相比于传统大规模MIMO面临更大挑战，主要原因有二：其一，large-MIMO系统无需相较于用户天线数量显著增加服务天线，因而缺乏有利传播条件；其二，当在large-MIMO系统中部署超大规模孔径阵列（ELAA）时，无线信道可能呈现空间非平稳性。本文提出一种名为ANPID的可扩展迭代大规模MIMO检测器，该检测器同时具备以下特性：1）接近最大似然检测性能；2）低计算复杂度（即发射天线数的平方阶）；3）快速收敛性；4）对ELAA信道空间非平稳性的鲁棒性。ANPID将阻尼解调步骤融入平稳迭代（SI）方法，并在两种不同的解调SI方法间交替运行。仿真结果表明，ANPID能够同时实现上述四种特性，并在高负载大规模MIMO系统中优于现有低复杂度MIMO检测器。