In this paper, we first give an overview of the coexistence of cellular with IEEE 802.11 technologies in the unlicensed bands. We then present a coexistence mechanism for Fifth-Generation (5G) New Radio on Unlicensed (NR-U) small cells located within buildings to coexist with the IEEE 802.11ad/ay, also termed as Wireless Gigabit (WiGig). Small cells are dual-band enabled operating in the 60 GHz unlicensed and 28 GHz licensed millimeter-wave (mmW) bands. We develop an interference avoidance scheme in the time domain to avoid cochannel interference (CCI) between in-building NR-U small cells and WiGig access points (APs). We then derive average capacity, spectral efficiency (SE), and energy efficiency (EE) performance metrics of in-building small cells. Extensive system-level numerical and simulation results and analyses are carried out for a number of variants of NR-U, including NR standalone, NR-U standalone, and NR-U anchored. We also analyze the impact of the spatial reuse of both mmW spectra of multiple NR-U anchored operators with a WiGig operator. It is shown that NR-U anchored provides the best average capacity and EE performances, whereas NR-U standalone provides the best SE performance. Moreover, both vertical spatial reuse intrabuilding level and horizontal spatial reuse interbuilding level of mmW spectra in small cells of an NR-U anchored can improve its SE and EE performances. Finally, we show that by choosing appropriate values of vertical and horizontal spatial reuse factors, the proposed coexistence mechanism can achieve the expected SE and EE requirements for the future Sixth-Generation (6G) mobile networks.

中文翻译：

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室内小基站毫米波频谱中5G NR-U（New Radio Unlicensed）共存的概述和机制

在本文中，我们首先概述了蜂窝与 IEEE 802.11 技术在未授权频段中的共存。然后，我们为位于建筑物内的未授权 (NR-U) 小基站上的第五代 (5G) 新无线电提出了一种共存机制，以与 IEEE 802.11ad/ay 共存，也称为无线千兆 (WiGig)。小型基站支持双频段，可在 60 GHz 未授权和 28 GHz 授权毫米波 (mmW) 频段中运行。我们开发了一种时域干扰避免方案，以避免室内 NR-U 小基站和 WiGig 接入点 (AP) 之间的同信道干扰 (CCI)。然后我们推导出室内小型基站的平均容量、频谱效率 (SE) 和能源效率 (EE) 性能指标。对 NR-U 的许多变体进行了广泛的系统级数值和模拟结果和分析，包括 NR 独立、NR-U 独立和 NR-U 锚定。我们还分析了多个 NR-U 锚定算子和 WiGig 算子的两个毫米波频谱的空间重用的影响。结果表明，NR-U 锚定提供最佳平均容量和 EE 性能，而 NR-U 独立提供最佳 SE 性能。此外，在NR-U锚定的小小区中，mmW光谱的垂直空间重用建筑物内水平和水平空间重用建筑物内水平都可以提高其SE和EE性能。最后，我们表明通过选择适当的垂直和水平空间重用因子值，