AI 中文总结
针对无小区毫米波大规模MIMO网络的非均匀空间业务分布，提出基于拟合优度检验的高能效接入点睡眠模式策略，可提升网络能量效率。
AI 中文摘要
无小区大规模多输入多输出（MIMO）是一种新型的后5G（B5G）和6G范式，它通过共用中央处理器（CPU）协调大量分布式接入点（AP），在同一时频资源上相干服务移动站（MS）。利用新的低拥塞毫米波（mmWave）频段的特性，这些网络可通过使用低复杂度的混合预编码器/解码器来提升整体系统的频谱和能量效率。为此，系统必须合理配置，以在不同业务负载条件下为MS提供所需的服务质量（QoS）。然而，在分析这些网络时通常仅考虑重业务负载条件，因此在低业务负载时段可能存在大量未充分利用的AP，导致资源利用效率低下和能源浪费。针对高能效AP开/关策略的实现，文献中已提出多种方法，但这些方法仅考虑整个覆盖区域内相当不现实的均匀空间业务分布。与现有工作不同，本文为无小区毫米波大规模MIMO网络提出了高能效AP睡眠模式技术，该技术能够捕捉实际无线网络中空间业务分布的非均匀特性。所提框架考虑、分析并比较了不同的AP开/关（ASO）策略，这些策略基于拟合优度（GoF）检验，专门设计用于动态开启/关闭AP，以适应网络中MS的数量和统计分布。数值结果表明，在非均匀空间业务分布下，使用精心设计的基于GoF的ASO策略可显著提升可实现的能量效率。
英文摘要
Cell-free massive multiple-input multiple-output (MIMO) is a novel beyond 5G (B5G) and 6G paradigm that, through the use of a common central processing unit (CPU), coordinates a large number of distributed access points (APs) to coherently serve mobile stations (MSs) on the same time/frequency resource. By exploiting the characteristics of new less-congested millimeter wave (mmWave) frequency bands, these networks can improve the overall system spectral and energy efficiencies by using low-complexity hybrid precoders/decoders. For this purpose, the system must be correctly dimensioned to provide the required quality of service (QoS) to MSs under different traffic load conditions. However, only heavy traffic load conditions are usually taken into account when analysing these networks and, thus, many APs might be underutilized during low traffic load periods, leading to an inefficient use of resources and waste of energy. Aiming at the implementation of energy-efficient AP switch on/off strategies, several approaches have been proposed in the literature that only consider rather unrealistic uniform spatial traffic distribution in the whole coverage area. Unlike prior works, this paper proposes energy efficient AP sleep-mode techniques for cell-free mmWave massive MIMO networks that are able to capture the inhomogeneous nature of spatial traffic distribution in realistic wireless networks. The proposed framework considers, analyzes and compares different AP switch ON-OFF (ASO) strategies that, based on the use of goodness-of-fit (GoF) tests, are specifically designed to dynamically turn on/off APs to adapt to both the number and the statistical distribution of MSs in the network. Numerical results show that the use of properly designed GoF-based ASO strategies under a non-uniform spatial traffic distribution can serve to considerably improve the achievable energy efficiency.
CommentsAuthor Accepted Manuscript. Published in IEEE Access, vol. 8, pp. 137587-137605, 2020. The final published version is available at: https://doi.org/10.1109/ACCESS.2020.3012199
Journal refJ. García-Morales, G. Femenias and F. Riera-Palou, "Energy-Efficient Access-Point Sleep-Mode Techniques for Cell-Free mmWave Massive MIMO Networks With Non-Uniform Spatial Traffic Density," in IEEE Access, vol. 8, pp. 137587-137605, 2020
DOI：10.1109/ACCESS.2020.3012199
