摘要
车路协同技术是解决自动驾驶中单车智能现存缺陷的关键技术。而智能网联高速公路的出现为车路协同技术真正应用于实际提供了良好的平台,其中,路侧单元(Road Side Unit, RSU)如何将路侧传感器信息或交通监控中心发布消息传递给路上车辆,是车路协同技术的一个关键环节。为此,提出一种基于V2V(Vehicle to Vehicle)和V2I(Vehicle to Infrastructure)融合的自适应数据分发协议(Adaptive Network and Road Traffic Data Dissemination for V2X, NRT-V2X)。NRT-V2X协议在影响通行效率事件的车流上游为RSU定义了一段服务区域(ROI, Region of Interest)。RSU通过感知服务区域中车辆的无线通信网络状况和路面交通状况来自适应调整其信息发送间隔,从而在保证ROI中车辆信息全覆盖的前提下,降低RSU发送信息开销,抑制ROI内车辆的接收信息冗余。基于创建的2个场景和2个车路协同应用,利用双向耦合车联网仿真平台进行性能评估。试验结果表明:采用NRT-V2X协议的车路协同技术可使高速公路的通行效率提高28%以上;与RSU固定发送间隔协议和典型V2X协议ATB相比,NRT-V2X的信息覆盖率稳定在100%,发送信息开销降低了至少30%,接收信息冗余下降了20%以上;NRT-V2X能够将智能网联高速公路通行效率相关信息高效地由RSU分发到其定义的ROI中的所有车辆,从而保证所有车辆预先接收到相关信息,选择最优行车路线,提高通行效率。
Intelligent vehicle infrastructure cooperative technique is the key to resolving the drawbacks of the current intelligent and autonomous vehicles. The development of a connected and automated highway makes this technique a potential platform. However, it is still a challenge to determine how the road side unit(RSU) disseminates the information from road side sensors or the traffic control center. This paper proposes an adaptive data dissemination protocol based on the fusion of V2 V and V2 I, named NRT-V2 X. The protocol defines a region of interest(ROI) before the event area in the upstream traffic direction. The RSU can adaptively adjust the transmit interval according to the network traffic and the road traffic in the ROI. Thus, the packet delivery ratio can be guaranteed to be near 100%, while decreasing the overhead of RSU and the network redundancy of vehicles. Two scenarios and applications were built on the bi-directional coupled IoV simulation platform, based on which the proposed technique can be evaluated. The NRT-V2 X can improve the traffic efficiency of highway by at least 28%. Moreover, unlike the fixed transmit interval method and ATB protocol, NRT-V2 X can ensure that the packet delivery ratio is close to 100%; the transmit overhead and received message redundancy decrease by more than 30% and 20%, respectively. Therefore, NRT-V2 X can efficiently disseminate traffic-related information to the vehicles in the ROI, and help the vehicles select an optimal trajectory leading to a shorter journey.
引文
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