基于传播图理论的真空管飞行列车的无线信道建模与容量分析

Wireless channel modeling and capacity analysis of vacuum tube flying train based on propagation graph theory

无线信道建模是分析和评估无线通信系统特性的重要环节。为了满足下一代轨道列车的通信需求,本文基于传播图信道建模理论,对真空管环境下列车在管道内运行过程中的无线电传播信道进行研究。结合朗伯散射模型和几何绕射理论模型进行仿真,过程中主要考虑了视距传输、单散射径、单散射加绕射三种情况。仿真得到了多输入多输出(multiple-input multiple-output,MIMO)条件下的信道传输矩阵,提取并分析了功率时延谱、K因子、多普勒谱和信道容量在列车处于不同位置时的变化情况,结果表明,所提出的模型有助于分析在真空管场景下MIMO系统的信道衰落特性和信道容量。

Wireless channel modeling is an important step in analyzing and evaluating the characteristics of wireless communication systems.In order to meet the communication requirements of the next generation of rail trains,this paper studies the radio transmission channel of trains running in tubes under vacuum tube environment based on the propagation graph channel modeling theory.Combined with Lambertian scattering model and geometric diffraction model,three cases of line-of sight transmission,single reflection path and single reflection plus diffraction are considered in the simulation process.The channel transmission matrix under the condition of multiple-input multipleoutput(MIMO)is simulated,and the power delay spectrum,K factor,Doppler spectrum and channel capacity are extracted and analyzed when the train is in different positions.The proposed model is helpful to analyze channel fading characteristics and channel capacity of MIMO system in vacuum tube scenarios.