Propagation and channel modelling for vehicular environments

智能交通系统(ITS)是一套新兴技术，将用于使城市中心或交通走廊沿线的陆地车辆运行更安全、更高效。由于在其应用中传递和交换的大部分信息是时间敏感和位置相关的，由车辆与路边单元或紧邻的其他车辆之间的无线链路组成的短程车辆网络近年来引起了人们的特别兴趣。这些网络的预期应用包括：(1)通过实时提供警告和警报来增强交通安全，(2)通过自适应地改变交通规则来缓解交通拥堵，(3)向司机提供位置相关的信息，(4)辅助交通法规的执行，(5)实现电子支付和收费，(6)协助方向和路线优化，(7)为出行者提供有关服务的信息，以及(8)实现自动化高速公路。由于车辆到车辆和车辆到路边的链路同时涉及终端和移动中的障碍物，它们经历了相对严重的衰落，这既是时间选择性的，也是频率选择性的。为了分析、设计和模拟短程车载网络，设计人员和开发人员需要能够捕获在这种环境中降低无线信号的传播损伤的信道模型。在该项目的过程中，我们将通过以下方式为在车辆环境中测量和建模短距离无线信道的全球努力做出贡献：(1)开发描述此类环境中的典型和极端操作场景的使用模型；(2)开发能够表征在此类环境中遇到的类型的时间和频率选择性信道的信道测量设备，也称为信道探测仪；以及(3)以对设计和开发人员有用的信道模型的形式捕获结果。

Intelligent transportation systems (ITS) are a suite of emerging technologies that will be used to make operation of land vehicles in urban centres or along transportation corridors safer and more efficient. Because much of the information that will be delivered and exchanged in ITS applications is time-sensitive and location-dependent, short-range vehicular networks that consist of wireless links between a vehicle and either roadside units or other vehicles in the immediate vicinity and that operate between 4.9 and 5.9 GHz have attracted particular interest in recent years. Anticipated applications of such networks include: (1) enhancing traffic safety by providing warnings and alerts in real time, (2) easing traffic congestion by adaptively changing traffic rules, (3) providing location-dependent information to drivers, (4) aiding traffic regulation enforcement, (5) enabling electronic payments and toll collection, (6) assisting in direction and route optimization, (7) providing information concerning services for travelers and (8) enabling automated highways. Because vehicle-to-vehicle and vehicle-to-roadside links involve both terminals and obstructions that are in motion, they experience relatively severe fading that is both time and frequency selective. In order to analyze, design and simulate short-range vehicular networks, designers and developers require channel models that capture the propagation impairments that degrade wireless signals in such environments. During the course of this project, we will contribute to the worldwide effort to measure and model short-range wireless channels in vehicular environments by: (1) developing usage models that describe both typical and extreme operating scenarios in such environments, (2) developing channel measurement equipment, also known as channel sounders, that are capable of characterizing time and frequency selective channels of the type encountered in such environments, and (3) capturing the results in the form of channel models useful to designers and developers.