基于车路协同多业务优先级的车载通信退避算法

为研究车路协同下不同优先级业务的通信，打破传统IEEE802.11 标准的CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance)协议所采用的二进制指数退避策略（Binary Exponential Backoff, BEB）仅适用于传统业务如语音、视频等业务，而未考虑车路协同场景典型业务及其优先级的限制，提出一种面向车路协同的车载通信退避算法。首先，研究车路协同场景下的典型通信业务；然后，利用层次分析法建立了业务优先级层次结构模型，对车路协同下的业务进行了优先级的划定；最后，基于车路协同多业务优先级不同对传统BEB算法进行改进，提出一种面向车路协同的车载通信退避算法。通过仿真，验证了所提算法具有良好的适应性，可针对不同业务优先级，提供差异化的信息资源和业务传输保障，相对于传统的通信协议系统丢包率降低，系统吞吐量增加。

Multiple-Service-Priority-Based Vehicular Communication Backoff Algorithm in Vehicle Infrastructure Cooperative System

In order to study the communication of different priority services under the Vehicle Infrastructure Cooperative System(VICS), break the restriction that the conventional Binary Exponential Backoff (BEB) algorithm adopted by Carrier Sense Multiple Access/Collision Avoidance(CSMA/CA) protocol under IEEE802.11 standard was only applicable to traditional services such as voice and video, etc., which ignored the typical services and their priorities of VICS, a multiple-service-priority-based vehicular communication backoff algorithm was proposed. Firstly, the typical communication services under VICS was studied; secondly, the VICS service models were constructed based on the priority by using Analytic Hierarchy Process(AHP) which defined the priority of the services in VICS; lastly, a multiple-service-priority-based vehicular communication backoff algorithm was proposed by improving traditional BEB algorithm based on different priority services in VICS. The simulation result shows that the proposed algorithm has good adaptability based on different service types, provides differentiated information resources and service transmission guarantee, the packet loss rate is reduced and the throughput is increased comparing with conventional scheme.