城市车载网络的路边单元部署机制

在支持车路通信的城市车载网络中,路边单元的部署方案影响着整个车载网络的性能,而传统的部署方案采用无线自组织网络中的布点方式,未充分考虑道路网络的拓扑结构和车辆移动的规律性,导致部署成本高和资源浪费.因此,本文提出了一种基于路口优先级和部署均匀性的路边单元部署机制,称为PUD(intersection Priority and deployment Uniformity based roadside unit Deployment scheme),保证其服务能力的同时降低部署成本.PUD以交叉路口作为路边单元的候选部署点,综合车辆移动特性和路网拓扑,以车流密度、连接中心性和公共交通线路数作为主要因素,计算每个交叉路口处部署路边单元的优先级,作为部署位置选择的标准.为了提高部署均匀性,避免路边单元的覆盖范围重叠导致的资源浪费,设置了四条部署约束规则,即位置约束、范围约束、优先级约束和覆盖约束,满足条件的交叉路口可被选择为部署位置.实验表明,与其他路边单元部署方案相比,PUD具有更低的部署成本、更高的覆盖率和车辆覆盖时间比例.

Roadside Unit Deployment Mechanism for Urban Vehicular Networks

In the vehicular networks with vehicle-to-infrastructure communication,the deployment of roadside units affects the performance of the entire networks.The traditional roadside unit deployment schemes use the deployment methods in wireless ad hoc networks,which do not fully consider the road network topology and the regularity of vehicle movement,resulting in a high deployment cost and resource waste.Therefore,this paper proposes a roadside unit deployment scheme based on intersection priority and deployment uniformity,namely PUD(intersection Priority and deployment Uniformity based roadside unit Deployment scheme),which guarantees the service capability and reduces deployment costs.PUD takes the intersections as the candidate deployment locations for RSUs and comprehensively considers the vehicle mobility features and the road network topology.For each intersection, PUD calculates its deployment priority as the criterion for the deployment location selection by utilizing the vehicle flow density, the connection centrality degree and the number of public routes through this intersection.In order to improve deployment uniformity and avoid resource waste caused by the overlapping of roadside units’ coverage areas,four deployment constraint rules are designed,namely the location constraint,the range constraint,the priority constraint and the coverage constraint.The intersections that meet the conditions can be selected as the deployment locations.Experiments show that compared with other roadside unit deployment schemes,PUD has lower deployment cost,higher coverage ratio,and higher coverage time ratio.