Research On Resource Allocation Algorithm Of V2X And Joint Control Technology For Vehicle Platooning

In recent years,with the continuous growth of vehicle ownership,society is faced with a series of serious problems such as frequent traffic accidents,road congestion,and serious environmental pollution.To solve the above social problems,vehicle platooning is a very effective means,which plays a significant role in improving road safety,increasing traffic throughput,and reducing fuel consumption.The performance of vehicle platooning depends greatly on the communication performance of the vehicle network.The highly reliable and low-latency vehicle-to-vehicle(V2V)communication enables platooning vehicles to drive more closely and achieve higher fuel economy.However,due to the scarcity of spectrum resources,the reliable communication of V2V cannot be guaranteed in high-density vehicle scenarios,which can dramatically decrease platooning performance,even leading to crashes.Therefore,how to improve spectrum utilization while ensuring the reliability of V2V communication,and how to improve the platoon driving performance when spectrum resources are scarce are the key research issues of this dissertation.For vehicle platooning,this dissertation starts from the perspective of resource allocation of V2X.It successively studies the platoon member communication,the platoon leader broadcast communication,and the integrated communication and longitudinal control of the platoon.Firstly,to enable high-density platooning,a resource allocation algorithm for concurrent communication with platoon members is studied.Secondly,to promote the coordination and management of the platoon,the method of reliable broadcast communication of the platoon leader is studied.Finally,the method of improving vehicle platooning performance is studied by integrating resource allocation algorithm and longitudinal driving technology.The main work and contributions of the dissertation are summarized as follows:1.For high-density vehicle scenarios,the reliability of V2V communication cannot be guaranteed.This dissertation proposes a reuse maximization algorithm while ensuring the reliability of V2V communication.Among them,the reliability of V2V communication is guaranteed by maintaining the constraints of links outage probability.The reliability and power control of the V2V communication are combined to model the reuse maximization problem of the V2V link.Using the upper bound of the link outage probability to transform the reuse maximization problem,the problem can be solved efficiently under the framework of the Perron-Frobenius Theorem.Further,for high-density vehicle platooning,which has strict requirements on the frequency and reliability of cooperative awareness message(CAM)exchange,based on the reuse maximization algorithm,a greedy resource allocation algorithm for platoon member V2V communication is proposed.The algorithm realizes the concurrent and reliable transmission of the platoon members,which can increase the frequency of exchanging CAM.The relationships between frequency reuse and platoon size,inter-vehicle distance,reliability constraints are analyzed by simulation,and the excellent performance of the proposed algorithm in frequency reuse is shown.2.Aiming at the problem of resource reuse is ignored when the dedicated spectrum is allocated to the platoon leader broadcast communication,and the problem that the communication reliability of platoon leader is difficult to guarantee due to the influence of long platoon and obstacles such as buildings,trees,and moving vehicles,a broadcast communication algorithm of joint relay node selection,power control,and mode selection is proposed.Firstly,based on the two-hop relay scheme,the minimization problems of transmission power in cellular mode,dedicated mode,and reusing mode are modeled respectively while ensuring the reliability of V2V communication.Secondly,in cellular mode,the base station is the relay node,and the problem can be solved directly.In dedicated mode,the problem can be transformed into a linear programming solution by selecting a relay node.In reusing mode,the problem is a mixed-integer nonlinear programming problem.The reusing problem is decomposed into three steps to solve,including power control,relay selection,reuse pairing.Finally,the mode selection algorithm is designed to reduce transmission power consumption and enable frequency reuse as much as possible under the premise of satisfying the reliable transmission of platoon leader information.The simulation results show that the proposed algorithm has great performance in frequency reuse,reliability,and power consumption.3.Aiming at the problem of how to ensure safety and stability of vehicle platooning and effectively suppress the increase of fuel consumption in the scenario of spectrum resource scarcity and frequent traffic perturbation,this dissertation proposes a modified distributed model predict control(DMPC)method by integrating control and V2X communication technology to achieve state convergence and fuel-saving in vehicle platooning.In the scenario of a shortage of spectrum resources,the motion information of the preceding vehicle obtained by onboard sensors is used to compensate for the safety problems faced by vehicles in the platoon.In addition,for frequent traffic perturbation,the V2V communication is used to monitor the movement of multiple vehicles in front,and a modified DMPC method is proposed to achieve fuel saving.To enable platoon members to monitor multiple vehicles ahead,a resource allocation scheme is proposed to maximize the V2V broadcast distance while ensuring the ergodic capacity requirement of cellular user(CUE)and the reliability of V2V broadcast communication.Simulation results show that the platoon can achieve state convergence.Compared with the existing algorithms,the proposed control algorithm has better fuel economy and fuel consumption stability when available resources decrease.