高机动无人机通信信道模拟器研制

Novel channel emulator for UAVs with high mobility

针对高机动无人机通信具有信道状态快速时变和直射路径强的特点,建立了一个包含直射径、反射径和多支路散射径的无人机信道模型,并据此设计实现了一种基于有限支路线性调频信号叠加的信道衰落模拟方法,该方法可用于实时产生连续相位的多径及阴影衰落。在此基础上,构建了一个基于数字信号处理器(DSP)和现场可编程门阵列(FPGA)的信道模拟器硬件实现方案,该方案结合DSP浮点运算和FPGA并行处理的优势,可有效模拟无人机通信信号的传播损耗、多径时延及复合衰落影响。实测结果表明,该模拟器输出的时变信道衰落幅值分布和动态多径时延均与理论结果吻合,可用于辅助无人机通信系统的方案设计、算法优化和性能测试。

The communication channels for unmanned aerial vehicles( UAVs) with high mobility have fast time-varying channel states and a strong direct path. First,a UAV communication channel model including the direct path,reflection path and multiple scattering paths is established. On this basis,a new generation method,namely the summation of linear-frequency-modulation signals,is presented to reproduce the multi-path fading and shadowing with continuous fading phases. Then,a new hardware implementation scheme combining the DSP and FPGA is constructed,which can take full advantage of the DSP and FPGA on the floating-point and parallel operations,respectively. The proposed scheme can be used to emulate the influence of path loss,path delay and composite fading on the transmitting signals. The measured results have shown that the output statistical properties,i. e.,the distribution of fading amplitude and path delay,are all consistent well with the theoretical ones,and the proposed emulator can be applied on the system design,algorithm optimization and performance evaluation of the UAV communication systems.