Underlay Radar-Massive MIMO Spectrum Sharing: Modeling Fundamentals and Performance Analysis
Underlay Radar-Massive MIMO Spectrum Sharing: Modeling Fundamentals and Performance Analysis
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DOI：
10.1109/twc.2021.3081458
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发表时间：
2020-08
影响因子：
10.4
通讯作者：
Raghunandan M. Rao;Harpreet S. Dhillon;V. Marojevic;Jeffrey H. Reed
中科院分区：
文献类型：
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作者：
Raghunandan M. Rao;Harpreet S. Dhillon;V. Marojevic;Jeffrey H. Reed
频谱共享通过两种或两种以上无线技术在同一频率资源上的和谐共存，缓解了低于6 GHz频段的严重频谱短缺。在这项工作中，我们研究了LOS/Near-LOS信道中的衬底雷达-大规模MIMO蜂窝共存，其中两个系统都具有3D波束形成能力。利用随机几何中的数学工具，我们推导了在最坏的“小区边缘波束形成”条件下，3D大规模MIMO蜂窝下行链路对雷达平均干扰功率的上界。为了克服非对称和任意大小区带来的技术挑战，我们设计了一种新的结构，其中每个泊松-沃罗诺伊(Poisson Voronoi，PV)小区以其外接圆为界，以约束随机小区形状对平均干扰的影响。由于相邻光伏电池的形状和大小之间的相关性，该模型很难进行进一步的分析，因此我们提出了一个易于处理的标称干扰模型，将每个光伏电池建模为一个圆盘，其面积等于典型光伏电池的平均面积。我们量化了这两种模型之间的平均干扰功率的差距，并表明对于实际的部署参数，上限是紧的。我们还将它们与一个更实用但更难处理的MU-MIMO调度模型进行了比较，结果表明，我们的最坏情况下的干扰模型显示出相同的趋势，并且没有明显偏离现实的调度器模型。在标称干涉模型下，通过推导典型接收机采用三维波束形成时的等干涉轮廓表达式，利用主导干涉者近似对干扰分布进行了表征。最后，我们使用干扰分布的易于处理的表达式来表征准静态目标跟踪场景中雷达虚警/检测的空间概率。我们的结果揭示了平均干扰作为部署参数(BS密度、隔离区半径、天线高度、每个BS的发射功率等)的函数的有用趋势。通过应用我们的分析结果来设计当前和未来雷达-蜂窝频谱共享场景中的最小隔离区半径，我们还使用雷达接收机工作特性(ROC)曲线提供了有用的系统设计见解。
Spectrum sharing alleviates the severe shortage of spectrum in sub-6 GHz frequency bands through the harmonious coexistence of two or more wireless technologies on the same frequency resources. In this work, we study underlay radar-massive MIMO cellular coexistence in LoS/near-LoS channels, where both systems have 3D beamforming capabilities. Using mathematical tools from stochastic geometry, we derive an upper bound on the average interference power at the radar due to the 3D massive MIMO cellular downlink under the worst-case ‘cell-edge beamforming’ conditions. To overcome the technical challenges imposed by asymmetric and arbitrarily large cells, we devise a novel construction in which each Poisson Voronoi (PV) cell is bounded by its circumcircle to bound the effect of the random cell shapes on average interference. Since this model is intractable for further analysis due to the correlation between adjacent PV cells’ shapes and sizes, we propose a tractable nominal interference model, where we model each PV cell as a circular disk with an area equal to the average area of the typical cell. We quantify the gap in the average interference power between these two models and show that the upper bound is tight for realistic deployment parameters. We also compare them with a more practical but intractable MU-MIMO scheduling model to show that our worst-case interference models show the same trends and do not deviate significantly from realistic scheduler models. Under the nominal interference model, we characterize the interference distribution using the dominant interferer approximation by deriving the equi-interference contour expression when the typical receiver uses 3D beamforming. Finally, we use tractable expressions for the interference distribution to characterize radar’s spatial probability of false alarm/detection in a quasi-static target tracking scenario. Our results reveal useful trends in the average interference as a function of the deployment parameters (BS density, exclusion zone radius, antenna height, transmit power of each BS, etc.). We also provide useful system design insights using radar receiver operating characteristic (ROC) curves by applying our analytical results to design the minimum exclusion zone radius in current and future radar-cellular spectrum sharing scenarios.