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更安全、更高效地运行。由于在ITS应用中传递和交换的大部分信息都是时间敏感和位置相关的，因此，由车辆与路边装置或附近其他车辆之间的无线链路组成的短距离车载网络近年来引起了人们的特别关注，该网络的工作频率在4.9至5.9 GHz之间。此类网络的预期应用包括：(1)通过提供实时警告和警报来提高交通安全；(2)通过自适应改变交通规则来缓解交通拥堵；(3)为驾驶员提供与位置相关的信息；(4)协助交通法规的执行；(5)实现电子支付和收费；(6)协助方向和路线优化；(7)为旅客提供有关服务的信息；(8)实现高速公路自动化。由于车对车和车对路边的连接涉及终端和运动中的障碍物，因此它们经历了相对严重的时间和频率选择性衰落。为了分析、设计和模拟短距离车辆网络，设计人员和开发人员需要信道模型来捕捉在这种环境中导致无线信号降级的传播障碍。在这个项目的过程中，我们将通过以下方式为全球范围内测量和模拟车载环境中的短距离无线信道做出贡献：(1)开发描述此类环境中典型和极端操作场景的使用模型；(2)开发能够表征此类环境中遇到的类型的时间和频率选择通道的通道测量设备，也称为通道测深器；(3)以对设计人员和开发人员有用的通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.