基于几何随机的无人机空地信道模型

针对传统无人机空地信道模型不支持三维飞行轨迹和三维天线的问题,通过引入空间旋转矩阵和轨迹参数,提出了一种基于几何随机的无人机空地三维信道改进模型。该模型结合无人机对地通信场景的特殊性,利用时变布尔变量描述视距路径、地面反射径和散射路径的动态生灭过程。同时,文中还给出了二维角度、时延和功率等模型参数的时间演进算法,用于复现无人机对地信道的时变统计特性。数值仿真结果表明,改进模型输出的空时相关特性和多普勒功率谱均与理论值吻合,并且自相关特性与实际测量结果基本一致,该模型可应用于辅助无人机空地无线通信设备的方案优化、算法验证和性能评估等领域。

Novel Geometry-Based Stochastic Model for UAV-Based Air-to-Ground Channels

Traditional unmanned aerial vehicle (UAV) air-to-ground channel models cannot support three-dimensional (3D) flight trajectories and 3D antenna arrays. In this paper, by introducing the spatial rotation matrix and trajectory parameters, a modified 3D geometry-based stochastic channel model for UAV-based air-ground links is proposed. Considering UAV air-to-ground communication scenarios, the proposed model adopts the time-varying Boolean variables to describe the dynamic birth and death processes of line-of-sight path, ground reflection path and other scattering paths. Meanwhile, the corresponding time-evolving algorithms of channel parameters, i.e., two-dimensional angle, delay and power, are given and analyzed. The upgraded method can be used to reproduce the time-variant statistical properties of UAV air-to-ground channels. The numerical simulation results have demonstrated that the output spatial-temporal correlation characteristics and Doppler power spectrum of our model are consistent well with the theoretical ones, and the auto-correlation characteristic agree well with the measured one. The proposed model is helpful for communication system optimization, algorithm verification and performance evaluation of UAV-based wireless communication equipment.