摘要
基于802.11p/WAVE的车联网是一项涉及道路交通、无线通信、自组织系统等多学科综合性的技术领域,车联网中,RSU单元可作为AP,让在行驶的汽车中的人们可以随时随地接入Internet,其中,如何建立RSU单元的下行流量模型是一个关键问题.通过引入车辆密度概率质量函数,分析车联网MAC层车辆通过RSU设备访问Internet的信道竞争情形,提出了适用于高速公路交通场景的RSU单元网络吞吐量模型,并推导出RSU上行及下行流量的性能解析式.针对RSU单元通信范围有限、相邻RSU单元之间可能存在盲区的问题,提出了一种利用同向行驶的车辆协助数据下载的VCo DS方案,以达到提高某时间段RSU的下行流量的目标.仿真实验结果证实,VCo DS方案可有效提高RSU单元的下行流量.
Abstract： VANET （vehicular adhoc network） based on 802.1 lp/WAVE is a comprehensive and systematic field of study which involves many subjects such as intelligent traffic system, wireless communication and self-organizing system. Roadside unit （RSU） works as IEEE 802.1 lp access points （APs） to open up services to clients from traveling vehicles for anytime and anywhere connection to Interact, thus making the modeling of downlink performance of RSU a key challenge. By introducing the vehicle density probability on freeway, the channel access contention scenarios of CSMA/DCF-based MAC layer well adapted to the time-varying vehicle arrivals are analyzed in detail. Then on that basis, the throughput performance model of VANET, including both the data downlink and the uplink through RSU for travelling vehicles, is presented. To address the issue of intermittent connectivity caused by RSU＇s inability to cover all the highway areas,VANET cooperative downloading scheme （VCoDS） is constructed to extend the downlink output of RSU. Simulations also verify the effectiveness of the proposed VCoDS scheme.
出处
《软件学报》
EI
CSCD
北大核心
2015年第7期1700-1710,共11页
Journal of Software
基金
国家自然科学基金(61373139)
教育部重点实验室开放基金(K93-9-2010-14)
江苏省自然科学基金(BK2012833)
江苏省博士后基金(1101136C)
江苏省高校自然科学研究项目(12KJB520011)
关键词
车联网
802.11p
协助下载
下行性能
流量
vehicular ad-hoc network
802.11 p
cooperative downloading
downlink performance
through output
