为评估车路协同系统的信息交互实际应用效果,以适应车路协同系统安全可靠的发展要求,测试基于广播式Wi-Fi的车路协同系统信息交互性能。选取丢包率和通信时延作为评价通信性能的代表性指标,构建实际道路交通场景并根据车速将其分为动态和静态两种类型。在不同通信距离和视距条件下设计4种详细的测试方案,在试验场的封闭道路上布设车载和路侧设备进行互相通信,通过采集和处理测试数据,分析通信距离、车速和视距对车路协同系统通信性能的影响。结果表明:通信距离和视距是丢包率最为明显的影响因素,通信距离越长,车路协同信息交互性能越差,丢包率越高,并且视距条件下的丢包率比非视距条件下低,而车速对丢包率无较大影响;车速、通信距离和视距均对通信时延影响不大。由此可知,通信距离和视距是导致基于广播式Wi-Fi的车路协同系统信息交互设备通信性能下降的重要因素,因此车路协同系统应保持在一定的通信距离范围和视距条件下进行信息交互,以确保不同种类消息传输的丢包率和通信时延达到要求值,满足实际道路上的应用要求。
Abstract
In order to evaluate the practical application effect of CVIS (Cooperative Vehicle Infrastructure System) information interaction and adapt to the development requirements of system security and reliability, the performance of CVIS information interaction based on broadcast Wi-Fi was tested. The packet loss rate and communication delay were selected as the test indicators of communication performance. Via constructing actual road traffic scenes divided into dynamic and static ones according to vehicle speed, and designing 4 detailed test schemes under different communication distance and line-of-sight conditions, the OBU (On-Board Unit) and RSU (Roadside Unit) were deployed in the closed test field to communicate with each other and the data was collected and processed to analyze the influence of distance, vehicle speed and line-of-sight on the communication performance of CVIS. The results showed that communication distance and line-of-sight were the most obvious influencing factors of packet loss rate, the farther the communication distance was, the worse the performance of CVIS information interaction was, and the higher the packet loss rate was; the packet loss rate under line-of-sight condition was lower than that under non line-of-sight condition, but the speed had no great influence on the packet loss rate; the speed, communication distance and line-of-sight had little influence on the communication delay. It can be seen that communication distance and line-of-sight are the important factors that lead to the degradation of communication performance of CVIS information interaction based on broadcast Wi-Fi. Therefore, CVIS should maintain information interaction within a certain communication range and line-of-sight conditions to ensure that the packet loss rate and communication delay of different kinds of message transmission reach the required value, so as to meet the application requirements on the actual road.
关键词
车路协同系统;封闭试验场;无线通信;丢包率;通信时延
Key words
CVIS (Cooperative Vehicle Infrastructure System); closed test field; wireless communication; packet loss rate; communication delay
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基金
中央级公益性科研院所基本科研业务费项目(20209024)