基于分布式合作的CAM消息均衡重构算法  

CAM reconstruction algorithm with network equilibrium and distributed cooperation

作　　者：肖广兵[1] 刘欣雨 孙宁[1] 张涌 XIAO Guang-bing;LIU Xin-yu;SUN Ning;ZHANG Yong(School of Automotive and Transportation Engineering,Nanjing Forestry University,Nanjing 210037,Jiangsu,China)

机构地区：[1]南京林业大学汽车与交通工程学院,江苏南京210037

出　　处：《长安大学学报（自然科学版）》2023年第5期119-128,共10页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(61803206);江苏省产业前瞻与共性关键技术重点项目(BE2017008-2);南京林业大学青年科学创新基金项目(CX2018004);南京林业大学大学生创新训练计划项目(202010298027Z)。

摘　　要：为了提高智能车队广播的可靠性和均衡性,针对智能车队中合作感知消息(cooperative awareness message,CAM)的频繁丢包问题,提出一种基于分布式合作的CAM消息均衡重构算法。首先将智能车队中奇数和偶数编号的车辆分别连接成2条虚拟线,然后将2条虚拟线的首尾对应相连以形成一个封闭的虚拟逻辑环,至此将智能车队的带状拓扑转换为环状拓扑,实现在智能车队中能够交互每个车辆的CAM消息重构任务。在此基础上,将智能车队沿着虚拟逻辑环分割成若干个相互交叠的博弈小组,通过建立合作博弈机制,实现交叠博弈小组之间对CAM消息重构策略的交互和修正,最终均衡分配车辆之间的CAM消息重构任务。采用NS2软件对CAM消息在智能车队内部的交互共享进行仿真试验,所有试验均采用相同的模拟配置:智能车队中的所有车辆均采用自组织时分复用(STDMA)机制来访问信道,并在其时隙内周期性广播CAM消息,车辆在每次传输中最多可以携带2条消息。研究结果表明:该算法在高密度车辆场景下的负载均衡度可达到0.940,平均消息接收率可达到85.1%;车辆之间的合作偏差最终逐渐减小并收敛于0,避免了大量冗余消息的转发,将平均延迟降低到180.385 ms。To improve the broadcast reliability and network load balance when distributing CAM among vehicles in a platooning,an equilibrium reconstruction algorithm via distributed cooperation was proposed to address the issue of frequent packet losses in the broadcasting of CAM.Firstly,both the odd-numbered and even-numbered vehicles in a platooning were connected into two virtual lines respectively,and then the end of the two virtual lines were linked together to form a closed virtual logic-ring.Thus,the topology of a platooning was modeled as a virtual logic-ring,and the task of CAM reconstruction could be somehow shared and negotiated among all vehicles along the virtual logic-ring.Specifically,all vehicles along the virtual logic-ring were divided into several overlapped game groups,and these vehicles keep exchanging and updating their strategies on how to recover the lost CAMs between overlapped game groups until a Nash equilibrium was achieved.NS2 was employed to simulate the process of cooperative CAM reconstruction in the platooning.For fair comparison,all vehicles used STDMA to access the radio channel for broadcasting,and each vehicle could carry two CAMs in each packet.The results show that the proposed algorithm can yield a high degree of network load balance as 0.940,whereas the average message reception rate can reach a high value of 85.1%.Meanwhile,the deviation in the game cooperation converge to 0 gradually,and the average time delay is cut down to 180.385 ms since redundant forwarding of CAMs is reduced.8 figs,27 refs.

关 键 词：汽车工程 智能车队 可靠广播 丢包 负载均衡 合作博弈 纳什平衡 

分 类 号：U461[机械工程—车辆工程]