车联网MAC层退避算法与信道预留策略研究
发布时间：2018-10-08 12:42
【摘要】：随着汽车在普通家庭中的普及,交通安全、效率以及行车体验慢慢得到了人们的关注。车联网属于智能交通,实现了车辆之间的相互通信,可以为用户提供安全行车与舒适的行车体验。它不仅可以提供安全信息来减少事故的发生,而且可以为车辆用户提供非安全的多媒体等娱乐信息。目前,它已经成为了智能交通领域的重要研究课题。车联网采用固定大小的竞争窗口以及二进制指数退避策略,不适应于不同车流密度的车辆环境。当车流密度较大时,固定的窗口和退避策略会导致大量的碰撞,增大了时延,影响了安全信息的传输；当车流密度较小时,固定的窗口和退避策略又会导致大量的空闲时间,造成信道资源的浪费。此外,在多信道协作方面,车联网采用了固定的切换周期。当车流密度较小时,安全信息相对较少,产生了大量的空闲时隙,导致了信道资源的浪费。 针对车联网中固定窗口和传统退避策略引起的信道接入问题,本文设计了一种自适应窗口的退避算法。通过建立广播的一维马尔科夫链模型,利用饱和吞吐量公式计算最优竞争窗口与节点数量的关系,设计基于节点数量自适应窗口的退避算法。仿真结果表明,该算法可以有效降低车联网的通信时延,增大了系统的吞吐量,并适用于不同的车流密度环境。针对信道切换引起的资源浪费问题,本文提出了一种基于信道预留的RCMAC协议。为了提高车流密度较少时信道资源的利用率,通过划分业务的优先级,建立信道状态表,利用空闲的控制信道时隙对服务信道进行预约,实现一种近似无竞争的服务信道接入方式。仿真结果表明,在车流密度小的情况下,该协议可以有效增加服务信道的吞吐量,降低不同优先级业务的传输时延。
[Abstract]:With the popularity of cars in ordinary families, traffic safety, efficiency and driving experience gradually get people's attention. The network of cars belongs to intelligent transportation, which realizes the mutual communication between vehicles, and can provide users with a safe and comfortable driving experience. It can not only provide safety information to reduce accidents, but also provide non-safe multimedia and other entertainment information for vehicle users. At present, it has become an important research topic in the field of intelligent transportation. The fixed size competition window and binary exponent Backoff strategy are used in the vehicle networking, which is not suitable for the vehicle environment with different traffic density. When the traffic density is high, the fixed window and Backoff strategy will lead to a large number of collisions, increase the delay, affect the transmission of security information, when the traffic density is small, the fixed window and Backoff strategy will lead to a lot of idle time. Causes the waste of channel resources. In addition, in the aspect of multi-channel collaboration, vehicle networking adopts a fixed switching period. When the traffic density is small, the security information is relatively less, resulting in a large number of idle time slots, resulting in a waste of channel resources. In order to solve the channel access problem caused by fixed window and traditional Backoff strategy in vehicle networking, an adaptive window Backoff algorithm is designed in this paper. By establishing a one-dimensional Markov chain model of broadcasting and calculating the relationship between the optimal competition window and the number of nodes by using the saturation throughput formula, a Backoff algorithm based on the adaptive window of the number of nodes is designed. The simulation results show that the proposed algorithm can effectively reduce the communication delay and increase the throughput of the system, and it is suitable for different traffic density environments. In order to solve the problem of resource waste caused by channel switching, a channel reservation based RCMAC protocol is proposed in this paper. In order to improve the utilization of channel resources when the traffic density is low, the channel status table is established by dividing the traffic priority, and the service channel is reserved by the idle control channel time slot. A kind of service channel access method without competition is realized. The simulation results show that the proposed protocol can effectively increase the throughput of the service channel and reduce the transmission delay of different priority services under the condition of low traffic density.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495;TP391.44;TN929.5
本文编号：2256790
[Abstract]:With the popularity of cars in ordinary families, traffic safety, efficiency and driving experience gradually get people's attention. The network of cars belongs to intelligent transportation, which realizes the mutual communication between vehicles, and can provide users with a safe and comfortable driving experience. It can not only provide safety information to reduce accidents, but also provide non-safe multimedia and other entertainment information for vehicle users. At present, it has become an important research topic in the field of intelligent transportation. The fixed size competition window and binary exponent Backoff strategy are used in the vehicle networking, which is not suitable for the vehicle environment with different traffic density. When the traffic density is high, the fixed window and Backoff strategy will lead to a large number of collisions, increase the delay, affect the transmission of security information, when the traffic density is small, the fixed window and Backoff strategy will lead to a lot of idle time. Causes the waste of channel resources. In addition, in the aspect of multi-channel collaboration, vehicle networking adopts a fixed switching period. When the traffic density is small, the security information is relatively less, resulting in a large number of idle time slots, resulting in a waste of channel resources. In order to solve the channel access problem caused by fixed window and traditional Backoff strategy in vehicle networking, an adaptive window Backoff algorithm is designed in this paper. By establishing a one-dimensional Markov chain model of broadcasting and calculating the relationship between the optimal competition window and the number of nodes by using the saturation throughput formula, a Backoff algorithm based on the adaptive window of the number of nodes is designed. The simulation results show that the proposed algorithm can effectively reduce the communication delay and increase the throughput of the system, and it is suitable for different traffic density environments. In order to solve the problem of resource waste caused by channel switching, a channel reservation based RCMAC protocol is proposed in this paper. In order to improve the utilization of channel resources when the traffic density is low, the channel status table is established by dividing the traffic priority, and the service channel is reserved by the idle control channel time slot. A kind of service channel access method without competition is realized. The simulation results show that the proposed protocol can effectively increase the throughput of the service channel and reduce the transmission delay of different priority services under the condition of low traffic density.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U495;TP391.44;TN929.5
【共引文献】
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1 荆涛;关明阳;;基于RFID技术的位置信息辅助系统[J];北京交通大学学报;2014年05期
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相关博士学位论文 前4条
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2 张秀华;基于WLAN/RFID信息融合的移动机器人自主定位算法研究[D];哈尔滨理工大学;2013年
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相关硕士学位论文 前4条
1 王勤龙;基于路侧设备的车辆定位和交叉口防撞预警方法研究[D];北京交通大学;2013年
2 刘庆;DTN网络中基于概率的散发等待路由算法[D];华中师范大学;2013年
3 张鹤丹;基于WiFi技术的井下人员定位系统研究[D];西安建筑科技大学;2013年
4 关明阳;面向RFID-VANETs的位置信息辅助系统[D];北京交通大学;2015年
，本文编号：2256790
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