基于数据优先级和车辆密度的安全数据的转发算法

摘要

In order to ensure the precision of safety data in VANET,the safety-related data often requires a higher priority and preferred dissemination,which the existing data dissemination algorithms of VANET cannot satisfy.In order to meet the demand of the differentiated transmission priorities of safety data in VANET,we propose a model of data priority and an algorithm of safety data dissemination based on data priority and vehicle density,called priority density transmit (PDT).Firstly,in order to differentiate the data priority of different packets,we propose a model of data priority,which assigns different priorities based on data state.Secondly,based on the difference of data priority and vehicle density,we propose an algorithm of safety data dissemination-PDT,which dynamically assigns the counter threshold and collision window based on data priority and vehicle density.Dynamically assigning the collision window can ensure the transmission order of data,and dynamically assigning the counter threshold cannot only ensure reliable transmission of data but also reduce the broadcast storm.We evaluate the performance of the PDT by comparing it with the counter-based algorithm and slotted-P algorithm.Simulation results show that the PDT can significantly improve vehicle throughput and packet delav,and reduce the broadcast storm.%在VANET中,为了保证安全数据的准确性和实时性,和安全相关的数据通常需要较高的优先级并且优先传输,现有的VANET数据转发算法不能满足这一点.为了满足VANET中安全数据的优先传输需求,提出了一种数据优先级模型,并基于数据优先级和车辆密度提出了一种安全数据转发算法.数据优先级模型可以给不同状态的数据分配相应的优先级;基于数据优先级和车辆密度的数据转发算法PDT动态分配计数器阈值和碰撞窗口,动态分配碰撞窗口可以确保数据的传输次序,而动态设定计数器阈值既能够保证数据的可靠传输又能有效地抑制广播风暴.仿真结果表明,与传统的counter-based数据转发算法和slotted-p数据转发算法相比,在数据吞吐量、传输时延和抑制广播风暴方面,PDT算法都有显著的性能提升.