基于几何统计的无人机信道模型及硬件模拟

针对无人机(unmanned aerial vehicle, UAV)通信信号三维空间传播特点,提出了基于多圆柱体的非平稳几何统计模型(geometry-based stochastic channel model, GSCM),该模型通过引入天线位置变换矩阵,可支持UAV〖JP2〗和地面移动端(mobile terminal,MT)任意三维移动轨迹。在此基础上,构建了适合硬件模拟实现的离散化模型,并设计实现了模拟时变信道特性的随机簇生灭算法,以及基于线性调频叠加原理的非平稳衰落模拟方法。硬件实测结果表明,本文信道模拟器输出的衰落幅值分布、时延功率谱和多普勒功率谱等统计特性与理论结果比较吻合,有效复现了信道时变衰落、多径时延、多径功率和多普勒频率随着UAV的位置和速度变化而变化的过程。

Geometry-based UAV channel modeling and its hardware emulation

For the three-dimensional (3D) propagation scenarios of unmanned aerial vehicle (UAV) communication, a multi-cylinder geometry-based stochastic channel model (GSCM) for non-stationary UAV channels is proposed in this paper. The model allows 3D arbitrary trajectories of the UAV as well as the mobile terminal (MT) on ground. On this basis, a corresponding discrete channel model suitable for hardware implementation is developed. Moreover, a birth-and-death algorithm of random cluster is designed to simulate the time-varying channel characteristics, and a new method, i.e., the summation of several linear frequency modulation signals, is applied to reproduce the non-stationary channel fading. Hardware measurement results show that the output statistical properties, i.e., fading amplitude distribution, delay power spectrum density (DPSD) and Doppler power spectrum density(DPSD) agree well with the theoretical ones, and they also clearly demonstrate the time evolving of channel parameters, e.g., the fading, path delay, path power and Doppler frequency, with the position and velocity variations of the UAV.