论文标题
$λ$ -MIMO：通过Modulo采样大规模MIMO
$λ$-MIMO: Massive MIMO via Modulo Sampling
论文作者
论文摘要
大量的多输入多输出（M-MIMO）体系结构是现代通信系统的主力。目前，两个基本的瓶颈，即功耗和接收器饱和，限制了该技术的全部潜在成就。这些瓶颈与在每个射频（RF）链中使用的类似物到数字转换器（ADC）复杂地联系在一起。 MIMO系统中的功耗随着ADC的位预算而成倍增长，而ADC饱和度会导致信息永久丢失。这激发了需要一种可以同时解决上述瓶颈的解决方案的需求，同时提供了比现有替代方案（例如低分辨率ADC）的优势。以根本不同的方法来解决此问题，我们建议使用Modulo ADC（$M_λ$ -ADC）而不是常规ADC的$λ$ -MIMO架构。我们的工作灵感来自无限的采样框架。 RF链中的$M_λ$ -ADC将高动态范围信号折叠到低动态范围模拟样本中，从而减轻了ADC饱和问题。同时，Modulo信号的数字化导致高分辨率量化。在新颖的$λ$ -MIMO上下文中，我们讨论了基带信号重建，检测和上行链路可实现的总和结果性能。我们工作的关键要点包括，（a）利用较高的信噪比噪声比（SQNR），（b）检测和平均上行链路总和率性能与常规的无限分辨率ADC相当，当时使用$ 1 $ 1 $ -2 $ -2 $ 2 $ 2 $ -2 $ $ $ $ $M_λ$ -ADC。这可以实现高阶调制方案，例如$ 1024 $ QAM似乎以前是不可能的，（c）能源效率和位预算之间的较高权衡，从而提高了功率效率。数值模拟和基于模型ADC的硬件实验证实了我们的理论，并增强了$λ$ -MIMO方法的明确好处。
Massive multiple-input multiple-output (M-MIMO) architecture is the workhorse of modern communication systems. Currently, two fundamental bottlenecks, namely, power consumption and receiver saturation, limit the full potential achievement of this technology. These bottlenecks are intricately linked with the analog-to-digital converter (ADC) used in each radio frequency (RF) chain. The power consumption in MIMO systems grows exponentially with the ADC's bit budget while ADC saturation causes permanent loss of information. This motivates the need for a solution that can simultaneously tackle the above-mentioned bottlenecks while offering advantages over existing alternatives such as low-resolution ADCs. Taking a radically different approach to this problem, we propose $λ$-MIMO architecture which uses modulo ADCs ($M_λ$-ADC) instead of a conventional ADC. Our work is inspired by the Unlimited Sampling Framework. $M_λ$-ADC in the RF chain folds high dynamic range signals into low dynamic range modulo samples, thus alleviating the ADC saturation problem. At the same time, digitization of modulo signal results in high resolution quantization. In the novel $λ$-MIMO context, we discuss baseband signal reconstruction, detection and uplink achievable sum-rate performance. The key takeaways of our work include, (a) leveraging higher signal-to-quantization noise ratio (SQNR), (b) detection and average uplink sum-rate performances comparable to a conventional, infinite-resolution ADC when using a $1$-$2$ bit $M_λ$-ADC. This enables higher order modulation schemes e.g. $1024$ QAM that seemed previously impossible, (c) superior trade-off between energy efficiency and bit budget, thus resulting in higher power efficiency. Numerical simulations and modulo ADC based hardware experiments corroborate our theory and reinforce the clear benefits of $λ$-MIMO approach.
