Massive multiple-input multiple-output (MIMO) is a key technology to meet the user demands in performance and quality of services (QoS) for next generation communication systems. Due to a large number of antennas and radio frequency (RF) chains, complexity of the symbol detectors increased rapidly in a massive MIMO uplink receiver. Thus, the research to find the perfect massive MIMO detection algorithm with optimal performance and low complexity has gained a lot of attention during the past decade. A plethora of massive MIMO detection algorithms has been proposed in the literature. The aim of this paper is to provide insights on such algorithms to a generalist of wireless communications. We garner the massive MIMO detection algorithms and classify them so that a reader can find a distinction between different algorithms from a wider range of solutions. We present optimal and near-optimal detection principles specifically designed for the massive MIMO system such as detectors based on a local search, belief propagation and box detection. In addition, we cover detectors based on approximate inversion, which has gained popularity among the VLSI signal processing community due to their deterministic dataflow and low complexity. We also briefly explore several nonlinear small-scale MIMO (2-4 antenna receivers) detectors and their applicability in the massive MIMO context. In addition, we present recent advances of detection algorithms which are mostly based on machine learning or sparsity based algorithms. In each section, we also mention the related implementations of the detectors. A discussion of the pros and cons of each detector is provided.

中文翻译：

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大规模 MIMO 检测技术：调查

大规模多输入多输出 (MIMO) 是满足用户对下一代通信系统性能和服务质量 (QoS) 需求的关键技术。由于大量天线和射频 (RF) 链，大规模 MIMO 上行链路接收器中符号检测器的复杂性迅速增加。因此，寻找具有最优性能和低复杂度的完美大规模 MIMO 检测算法的研究在过去十年中受到了广泛关注。文献中已经提出了大量的大规模 MIMO 检测算法。本文的目的是为无线通信通才提供有关此类算法的见解。我们收集了大规模 MIMO 检测算法并对它们进行了分类，以便读者可以从更广泛的解决方案中找到不同算法之间的区别。我们提出了专为大规模 MIMO 系统设计的最优和接近最优检测原理，例如基于局部搜索、置信传播和框检测的检测器。此外，我们还介绍了基于近似反演的检测器，由于其确定性数据流和低复杂性，它在 VLSI 信号处理社区中很受欢迎。我们还简要探讨了几种非线性小规模 MIMO（2-4 个天线接收器）检测器及其在大规模 MIMO 环境中的适用性。此外，我们介绍了检测算法的最新进展，这些算法主要基于机器学习或基于稀疏性的算法。在每个部分，我们还提到了检测器的相关实现。提供了每个检测器的优缺点的讨论。