摘要:由于车辆节点与路边设施的强大存储与计算能力、良好的无线通信能力以及不间断的能量供应，车载自组网（vehicular ad-hoc network，简称VANET）可检测车辆行驶环境的变化，评测危险路况并预警，如前方事故现场预警、交叉路口防碰撞预警等，预估司机的反应时间，为安全驾驶及驾驶体验提供技术支持.但VANET中，数据传输面临无线信道质量不稳定、网络拓扑瞬息万变、无线链路寿命短、带宽受限、通信负载量大等多重挑战.因此，如何将数据及时而可靠地传输到"城市大脑"，已成为一个研究热点.考虑存储成本、丢包惩罚与传输奖励，首先提出了面向VANET的混合流调度策略，为不同优先级的数据流分配传输资源；结合链路状况，接着提出了VANET中混合流调度与路径选择联合优化的数据传输策略，满足了强实时数据流对传输时延的需求，同时提高了弱实时数据流的传输可靠性.大量的仿真实验与性能分析表明，这些策略能够为VANET中数据传输提供QoS保障.



Abstract:Due to the powerful storage and computing capability, wireless communication capability and abundant energy supply of vehicle nodes and roadside facilities, the vehicular ad-hoc network (VANET) can detect change of vehicle driving environment, evaluate dangerous road conditions and warn drivers, such as warning of accident sites, collision prevention at intersections, predict the reaction time of drivers, so as to provide technical support for safe driving and driving experience. However, data transmission in a VANET faces multiple challenges, such as unstable wireless channel quality, time-varying network topology, short lifetime of wireless links, limited bandwidth and large communication load. Therefore, how to transmit data timely and reliably to the "urban brain" has become a issue. Taking storage cost, packet loss penalty and transmission reward into account, In this paper, a hybrid flow scheduling strategy for VANETs is first proposed, which allocates transmission resources for data flows with different priorities; then, combined with link status, a data transmission strategy for joint optimization of hybrid flow scheduling and path selection is introduced to meet the requirement on delay for real-time data and improve reliability for non real-time at the same time. Simulation results and analysis demonstrate the performance of proposed strategies.



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