Propagation Measurements and Analyses at 28GHz on NSF POWDER

IEEE ICC 2023: Propagation Measurements and Analyses at 28GHz via an Autonomous Beam-Steering Platform This paper details the design of an autonomous alignment and tracking platform to mechanically steer directional horn antennas in a sliding correlator channel sounder setup for 28-GHz V2X propagation modeling. A pan-and-tilt subsystem facilitates uninhibited rotational mobility along the yaw and pitch axes, driven by open-loop servo units and orchestrated via inertial motion controllers. A geo-positioning subsystem augmented in accuracy by real-time kinematics enables navigation events to be shared between a transmitter and receiver over an Apache Kafka messaging middleware framework with fault tolerance. Herein, our system demonstrates a 3D geo-positioning accuracy of 17 cm, an average principal axes positioning accuracy of 1.1 degrees, and an average tracking response time of 27.8 ms. Crucially, fully autonomous antenna alignment and tracking facilitates continuous series of measurements, a unique yet critical necessity for millimeter wave channel modeling in vehicular networks. The power-delay profiles, collected along routes spanning urban and suburban neighborhoods on the NSF POWDER testbed, are used in pathloss evaluations involving the 3GPP TR38.901 and ITU M.2135 standards. Empirically, we demonstrate that these models fail to accurately capture the 28-GHz pathloss behavior in urban foliage and suburban radio environments. In addition to RMS direction-spread analyses for angles-of-arrival via the SAGE algorithm, we perform signal decoherence studies wherein we derive exponential characteristics of the spatial autocorrelation coefficient under distance and alignment effects. Note: This is a smaller version of our dataset. The original dataset collected on the NSF POWDER testbed is approximately 400 GB. Due to Zenodo's size restrictions, the data uploaded here contains only a few of our calibration (USRP 76 dB gain) and measurement logs (fully-autonomous V2X routes onsite). To gain access to our complete dataset, please contact the authors at <[e-mail]> or <[e-mail]>. Additional measurements in our full dataset include USRP 0 dB calibration results; fully-autonomous urban-stadium-van, urban-campus-cart, and urban-presidents-circle-full-van routes; and semi-autonomous (and manual) urban-garage-cart and urban-campus-cart routes.IEEE ICC 2023：基于自主波束调控平台的28GHz传播测量与分析 本文详述了一款自主对准与跟踪平台的设计方案，该平台可在滑动相关器信道探测仪架构中对定向喇叭天线进行机械波束调控，用于28GHz车到万物（Vehicle to Everything, V2X）传播建模。该平台包含方位-俯仰子系统，依托开环伺服单元驱动，通过惯性运动控制器实现偏航与俯仰轴方向的无限制旋转移动。经实时运动学校准提升定位精度的地理定位子系统，可通过具备容错能力的Apache Kafka消息中间件框架，实现发射机与接收机之间的导航数据共享。经测试，本系统的三维地理定位精度可达17厘米，主轴平均定位精度为1.1度，平均跟踪响应时间为27.8毫秒。至关重要的是，全自主的天线对准与跟踪功能可实现连续批量测量，这正是车载网络毫米波信道建模所必需且独有的关键条件。 本数据集采集自NSF POWDER测试平台的城市与郊区道路场景的功率时延谱，用于基于3GPP TR38.901与ITU M.2135标准的路径损耗评估。实验结果表明，现有模型无法精准复现城市植被区与郊区无线环境中的28GHz路径损耗特性。除了通过SAGE算法对到达角进行均方根（Root Mean Square, RMS）角度扩展分析外，本研究还开展了信号去相干研究，推导了距离与对准误差影响下空间自相关系数的指数特性。 注意：本数据集为完整数据集的精简版本。在NSF POWDER测试平台采集的原始数据集容量约为400GB。受Zenodo的文件大小限制，本次上传的数据仅包含部分校准数据（通用软件无线电外设（Universal Software Radio Peripheral, USRP）76dB增益校准）与测量日志（现场全自主V2X行驶路线数据）。 若需获取完整数据集，请联系作者：<[e-mail]> 或 <[e-mail]>。完整数据集包含的额外测量数据包括：USRP 0dB增益校准结果；全自主行驶路线数据（城市体育场-厢式车、校园-手推车、总统环岛-全厢式车）；以及半自主（含手动）行驶路线数据（城市车库-手推车、校园-手推车）。