【作者】 王玮；

【导师】 谭国真；

【作者基本信息】 大连理工大学 ， 计算机应用技术， 2014， 硕士

【摘要】 随着车辆所携带的无线移动设备的大量增加,出现了车联网应用技术来更好的组织和管理道路上车辆所形成的无线网络。车联网以改善交通安全状况、提高运输效率、方便人们出行为目标,对未来的交通系统产生深远的影响。车联网己成为智能交通领域研究的新热点,受到国际工业界和学术界的共同关注,已有越来越多的研究人员投入到车联网研究当中。其中车联网的信息传输机制对支持各类交通安全及娱乐相关应用具有重要意义。车联网中实现高效的信息传输机制具有非常大的挑战性,需要考虑交通环境中车辆节点快速移动及稠密交通数据冗余等实际特性和约束。在众多车联网信息分发策略研究中,Waild等人提出一种路侧单元之间协作的合作式车路通信模型,该模型中设计了一种充分发挥车辆间共享信息能力的路侧单元协作策略,目的是提高网络中传输数据的多样性,并利用联盟博弈(CGS)方法将骨干网中的路侧单元划分为协作联盟来协调管理,但是该策略需要成员对联盟中其他所有成员有所贡献才能加入联盟,这样带来的不足是没有考虑一个成员对某一联盟中部分成员有贡献,而对剩余成员的影响可以忽略的情况。另有基于图划分理论的路侧单元联盟形成策略,联盟内部成员依赖路网拓扑关系进行协作而不能更加灵活地协调各成员的协作关系。而且在单行路环境中因不能发掘相对行驶车辆共享信息的能力而变得低效。针对以上问题,本文通过分析路侧单元间协作通信特点提出基于遗传算法的路侧单元协作联盟划分(CFGA)策略,选择合适的编码方式充分表达骨干网路侧单元的联盟组成及联盟内部成员间的协作关系,保证种群初始化、选择操作和交叉操作产生的个体是符合路网拓扑的合理个体,并利用边界基因变异有效实现解空间的局部搜索。针对路侧单元间协作通信在单行路上的局限性提出车辆向后方共享信息的策略,利用集合覆盖原理选择共享中继车辆使共享信息重复转发次数降低。更多还原

【Abstract】 With the significant increase of vehicle wireless mobile devices, Vehicular Networks(VANET) appears,which can better organize and manage wireless network consisting of vehicles. VANET aims at improving traffic safety conditions, enhancing transport efficiency and facilitating people travelling. Increasing researchers focus on VANET in industry and academia as VANET has been a hotspot of ITS. The information transfer mechanism in VANET is important to supporting various kinds of applications that is related to traffic safety and entertainment.Achieving efficient information transfer mechanism is a huge challenge in VANET, considering fast moving vehicles and data redundancy associated with dense traffic. Waild, et al proposed a novel cooperation protocol depending on the content sharing possibilities of the underlying communications between vehicles in the opposite direction. Then Coalition Formation Games(CGS) is proposed to dividing RSUs into different coalitions for the coordination of RSUs. But a member must contribute to each member belonging to the same coalition. And the coalition formation based on graph partition theory results in the cooperation among RSUs is not flexible. In addition, the cooperation protocol is inefficient on one-way road because the content sharing possibilities of the underlying communications between vehicles in the opposite direction is low.Aiming at problems above, this paper proposes a Coalition Formation based on Genetic Algorithm(CFGA) strategy by analyzing characteristics of the cooperation protocol. A diversity of cooperation among RSUs can be represented with appropriate genetic representation. Qualified solutions that accord with road topology can be generated by initialization, Selection and Crossover. Local searching of solution space can be implemented by margin gene mutation. Considering the limitation of the cooperation protocol on one-way road, this paper proposes the strategy that vehicles share information backwards and selects (Multipoint Relay)MPR vehicles based on set cover to reducing redundancy forwarding data.更多还原