高速流变类隧道环境下的ETC系统信道分析与建模

The multi-lane-free-flow (MLFF) makes the transmission channel of Electronic Toll Collection (ETC) with random time-varying and non-stationary characteristics, which effect on the system trading reliability. The project is based on the thought of geometry stochastic modeling method, and grasps the vehicles geometry characteristics and the traffic flow distribution status as the breakthrough point. With fractal geometry, traffic flow theory, percolation theory and stochastic analysis method, firstly, the influence rule which the irregular geometry act on the propagation mechanism of radio waves is revealed. Then, the equivalent model of scatterer for vehicles with different car body structures is set up. Secondly, the random process with rising and vanishing of multipath signal in rheological tunnel-like environment is explored, and the closed-form expressions of relevant parameters for non-stationary channel are acquired. Thirdly, the spatial domain, time domain, and frequency domain character of multipath propagation under the random walk of vehicles are revealed, and the dynamic stochastic channel model of ETC integrated with traffic flow character is established. Finally, the project researches the simulation realization technology of stochastic dynamic heterogeneous distribution of scatterers, and a simulation testing scenario is built to verify the channel model present. Therefore, the results of the project expand the research approach of modeling and measurement of channel for fixed to mobile communication terminal. On the other hand, results of the project can provide technical support for the ETC system design and deployment, and promote the applying potential of vehicle communication technology. It has an important significance of scientific research and practical application value.

多车道自由流（MLFF）使得电子不停车收费（ETC）系统传播信道具有随机时变和非平稳特征，影响系统交易可靠性。本项目基于几何随机建模思想，以车辆几何特征和交通流分布状态为切入点，应用分形几何学、交通流理论、渗流理论和随机分析等方法，①研究不同车体结构车辆的反散射空间等效模型，揭示不规则几何体对电波传播机制的影响规律；②探索流变类隧道环境中多径信号的随机生灭过程，推导非平稳信道相关参数的闭合表达式；③探究MLFF应用场景中信道散射体的空间分布状态，揭示车辆随机游动情形下信道多径传播的空域-时域-频域特性，建立融入交通流特征的系统动态随机性信道模型；④研究随机动态非均匀分布反散射体的模拟实现技术，构建模拟场景，验证信道模型。本项目成果拓宽固定-移动终端通信信道测量和建模的研究思路，为ETC系统设计和部署提供技术支撑，提升车载通信技术应用潜力，具有重要的科学研究意义和实际应用价值。

基于射频识别(RFID)和专用短程通信技术的电子不停车收费（ETC）系统是车-路通信的典型应用。多车道自由流(MLFF)应用模式，其交通断面所有车道均采用ETC模式，已成为现代交通发展的必然趋势。MLFF应用模式下，相邻车道内车辆间隔变小，旁道车辆的影响增大；此外，长头卡车、轿车、大客车等不同外形、长度、速度和加速度特征的多种车辆混合交通、多车道换道行为、及驾驶员多自主行为主体特征，使得路面交通流构成一个随机时变的流变类隧道物理环境；周围车辆的干扰使得传播信道中远近端反散射体数目也随之增加，信道中多径结构分布特性发生改变；同时，车辆的高速运动加剧了因移动所引起的环境变化对电波传播的影响，多普勒效应加剧，信道参数的统计特性也随之改变，传统广义平稳假设不再适用，多径传播的小尺度快衰落特征不再恒定。.本项目从车辆几何特征和交通流分布状态入手，兼顾信道模型的精确性和复杂性，在车辆反散射空间等效、多径信号的动态跟踪、ETC信道建模及模拟场景实现技术方面开展了深入研究，提出了基于车辆几何特征的反散射空间等效、基于分簇的多径信号动态跟踪、基于交通流特征的ETC信道建模以及基于软件定义无线电技术的应用场景模拟实现技术。本项目发表论文23篇，获授权发明专利2项，正在实审4项，计算机软件著作权1项。项目成果作为成果支撑，获得2018年度中国电工学会科学技术奖二等奖、2020年度安徽省技术发明奖二等奖。项目培养博士生2人，硕士生5人。本项目研究对车联网的设计、部署和推广应用具有重要的科学研究意义和实际应用价值；同时，对一些特色应用场景传播信道的分析、无线通信系统设计及部署具有借鉴意义。.