Research On Roadside Unit Placement For Traffic Flows Coverage In Vehicular Networks

As an important infrastructure in the vehicular networks,the RoadSide Unit(RSU)is mainly used to implement the communication of vehicle to infrastructure.RSU is a key device for achieving intelligent road and vehicle-road coordination.The RSU is mainly located on the roadside,and performs two-direction communication and data exchange with passing vehicles.The RSU is an important device to realize various functions in the vehicular networks.However,due to the high placement cost,it is necessary to find the optimal location to place the RSU,which makes the budget the lowest.This thesis studies the relationship between traffic flow coverage requirements and placement costs.Firstly,the thesis studies how to minimize placement costs when the coverage requirements is certain.Full placement and incremental placement are proposed according to the different placement requirements.Full placement is used to meet the coverage requirements when the requirement is certain.Incremental placement refers to the fact that although there are some RSU in the system,the existing RSU can't meet the increasing coverage requirements,and the more RSU is needed to placed.Firstly,the problem model is established and complexity of the problem is proved.Then,the greedy deployment algorithm GDA and the incremental weight deployment algorithm IDW are proposed to solve the full placement problem and incremental placement problem.Finally,the feasibility of the algorithms are verified by simulation experiment in different scenarios.Secondly,the thesis studies how to place to make the given traffic flows pass the number of RSU the largest when the budget is limited.Through considering the relationship between different traffic flows,the value range of RSU the traffic flow passing through at least and the placed RSU on each traffic flow can be known according to the pigeonhole principle.The optimal placement position of RSU is derived and generalized to general,and the greedy coverage placement strategy is proposed.Then,considering the impact of RSU which have been placed,the greedy coverage placement strategy is improved and greedy incremental strategy is proposed.Through a large number of experiments,it is shown that the two proposed algorithms can achieve better coverage requirements for the given traffic flow when the budget is limited.In summary,the thesis proposes different RSU placement algorithms by discussing the relationship between coverage requirement and budget,and the thesis verifies the effectiveness of the proposed algorithm through theoretical analysis and experiments,which provides the technical support for the placement of RSU in the internet of vehicles.