针对车联网中消息多样性与多模态的混合传输需求,多网络介质融合已成为构建车联网网络的必然趋势.如何根据通信需求优化网络资源已成为车联网中亟待解决的问题.基于传统网络协议,本文针对数据链路层协议中调度算法,提出了异构车联网逻...针对车联网中消息多样性与多模态的混合传输需求,多网络介质融合已成为构建车联网网络的必然趋势.如何根据通信需求优化网络资源已成为车联网中亟待解决的问题.基于传统网络协议,本文针对数据链路层协议中调度算法,提出了异构车联网逻辑链路控制层(Logical Link Control,LLC)链路调度算法(HetVNETs Link Scheduling Algorithm in LLC,HLSA).该算法将车联网中交通流密度、数据报文优先级和链路通信状态作为参数,对车联网中不同链路进行调度.首先,根据车联网协议标准,本文定义了四种数据优先级.同时,定义了RTT因子和拥塞因子对数据链路层协议中各个路径状态进行表征.并且,设计了链路相似度(Data Priority-based Link Similarity,DPLS)为分发数据报文提供调度依据.该相似度利用路径中待交互数据报文的优先级与已缓存的数据报文优先级的相似度进行统计.其次,利用Pareto最优计算出IEEE 802.11p链路中非安全短消息数据报文的最大分发频率上界.基于DPLS和该最大分发频率上界,最终设计并实现了面向数据报文优先级的链路调度算法,并根据理论分析,给出算法的时间复杂度为O(n).最后,根据稀疏、中等、密集和极度密集四种交通拥塞场景进行大量实验验证,证明了HLSA算法相对于现有算法,在面向安全与非安全数据报文混合传输场景中数据链路层链路调度算法的有效性.展开更多
为研究车联网环境下异质交通流的演变规律,基于改进的NaSch模型,针对智能网联化程度的前期、中期和后期分别进行仿真实验,得到交通流基本图,并分析通行能力与网联车渗透率的内在联系;其次,通过马尔可夫链证明了网联车形成的有序排列能...为研究车联网环境下异质交通流的演变规律,基于改进的NaSch模型,针对智能网联化程度的前期、中期和后期分别进行仿真实验,得到交通流基本图,并分析通行能力与网联车渗透率的内在联系;其次,通过马尔可夫链证明了网联车形成的有序排列能提高道路通行能力,随机仿真实验验证了理论推导的正确性;最后,引入考虑车辆排列方式的相对熵,从而定量描述异质车流的有序性,阐明了智能网联车辆(connected and autonomous vehicle,CAV)改善交通状况的本质原因.研究结果表明:随着智能网联车渗透率的增加,通行能力增加,在智能网联化前期,渗透率的增加对通行能力提升较小,最高仅提升23.5%,中、后期通行能力最高能提升125.0%;在一定交通密度下,CAV渗透率与流量呈现正相关,相对熵与流量呈现负相关;智能网联车处于分离态时相对熵较小,分离态对随机混合的通行能力的提升随着CAV渗透率的增加而降低.展开更多
With the development of intelligent and interconnected traffic system,a convergence of traffic stream is anticipated in the foreseeable future,where both connected automated vehicle(CAV)and human driven vehicle(HDV)wi...With the development of intelligent and interconnected traffic system,a convergence of traffic stream is anticipated in the foreseeable future,where both connected automated vehicle(CAV)and human driven vehicle(HDV)will coexist.In order to examine the effect of CAV on the overall stability and energy consumption of such a heterogeneous traffic system,we first take into account the interrelated perception of distance and speed by CAV to establish a macroscopic dynamic model through utilizing the full velocity difference(FVD)model.Subsequently,adopting the linear stability theory,we propose the linear stability condition for the model through using the small perturbation method,and the validity of the heterogeneous model is verified by comparing with the FVD model.Through nonlinear theoretical analysis,we further derive the KdV-Burgers equation,which captures the propagation characteristics of traffic density waves.Finally,by numerical simulation experiments through utilizing a macroscopic model of heterogeneous traffic flow,the effect of CAV permeability on the stability of density wave in heterogeneous traffic flow and the energy consumption of the traffic system is investigated.Subsequent analysis reveals emergent traffic phenomena.The experimental findings demonstrate that as CAV permeability increases,the ability to dampen the propagation of fluctuations in heterogeneous traffic flow gradually intensifies when giving system perturbation,leading to enhanced stability of the traffic system.Furthermore,higher initial traffic density renders the traffic system more susceptible to congestion,resulting in local clustering effect and stop-and-go traffic phenomenon.Remarkably,the total energy consumption of the heterogeneous traffic system exhibits a gradual decline with CAV permeability increasing.Further evidence has demonstrated the positive influence of CAV on heterogeneous traffic flow.This research contributes to providing theoretical guidance for future CAV applications,aiming to enhance urban road traffic effi展开更多
文摘针对车联网中消息多样性与多模态的混合传输需求,多网络介质融合已成为构建车联网网络的必然趋势.如何根据通信需求优化网络资源已成为车联网中亟待解决的问题.基于传统网络协议,本文针对数据链路层协议中调度算法,提出了异构车联网逻辑链路控制层(Logical Link Control,LLC)链路调度算法(HetVNETs Link Scheduling Algorithm in LLC,HLSA).该算法将车联网中交通流密度、数据报文优先级和链路通信状态作为参数,对车联网中不同链路进行调度.首先,根据车联网协议标准,本文定义了四种数据优先级.同时,定义了RTT因子和拥塞因子对数据链路层协议中各个路径状态进行表征.并且,设计了链路相似度(Data Priority-based Link Similarity,DPLS)为分发数据报文提供调度依据.该相似度利用路径中待交互数据报文的优先级与已缓存的数据报文优先级的相似度进行统计.其次,利用Pareto最优计算出IEEE 802.11p链路中非安全短消息数据报文的最大分发频率上界.基于DPLS和该最大分发频率上界,最终设计并实现了面向数据报文优先级的链路调度算法,并根据理论分析,给出算法的时间复杂度为O(n).最后,根据稀疏、中等、密集和极度密集四种交通拥塞场景进行大量实验验证,证明了HLSA算法相对于现有算法,在面向安全与非安全数据报文混合传输场景中数据链路层链路调度算法的有效性.
文摘为研究车联网环境下异质交通流的演变规律,基于改进的NaSch模型,针对智能网联化程度的前期、中期和后期分别进行仿真实验,得到交通流基本图,并分析通行能力与网联车渗透率的内在联系;其次,通过马尔可夫链证明了网联车形成的有序排列能提高道路通行能力,随机仿真实验验证了理论推导的正确性;最后,引入考虑车辆排列方式的相对熵,从而定量描述异质车流的有序性,阐明了智能网联车辆(connected and autonomous vehicle,CAV)改善交通状况的本质原因.研究结果表明:随着智能网联车渗透率的增加,通行能力增加,在智能网联化前期,渗透率的增加对通行能力提升较小,最高仅提升23.5%,中、后期通行能力最高能提升125.0%;在一定交通密度下,CAV渗透率与流量呈现正相关,相对熵与流量呈现负相关;智能网联车处于分离态时相对熵较小,分离态对随机混合的通行能力的提升随着CAV渗透率的增加而降低.
基金Project supported by the Fundamental Research Funds for Central Universities,China(Grant No.2022YJS065)the National Natural Science Foundation of China(Grant Nos.72288101 and 72371019).
文摘With the development of intelligent and interconnected traffic system,a convergence of traffic stream is anticipated in the foreseeable future,where both connected automated vehicle(CAV)and human driven vehicle(HDV)will coexist.In order to examine the effect of CAV on the overall stability and energy consumption of such a heterogeneous traffic system,we first take into account the interrelated perception of distance and speed by CAV to establish a macroscopic dynamic model through utilizing the full velocity difference(FVD)model.Subsequently,adopting the linear stability theory,we propose the linear stability condition for the model through using the small perturbation method,and the validity of the heterogeneous model is verified by comparing with the FVD model.Through nonlinear theoretical analysis,we further derive the KdV-Burgers equation,which captures the propagation characteristics of traffic density waves.Finally,by numerical simulation experiments through utilizing a macroscopic model of heterogeneous traffic flow,the effect of CAV permeability on the stability of density wave in heterogeneous traffic flow and the energy consumption of the traffic system is investigated.Subsequent analysis reveals emergent traffic phenomena.The experimental findings demonstrate that as CAV permeability increases,the ability to dampen the propagation of fluctuations in heterogeneous traffic flow gradually intensifies when giving system perturbation,leading to enhanced stability of the traffic system.Furthermore,higher initial traffic density renders the traffic system more susceptible to congestion,resulting in local clustering effect and stop-and-go traffic phenomenon.Remarkably,the total energy consumption of the heterogeneous traffic system exhibits a gradual decline with CAV permeability increasing.Further evidence has demonstrated the positive influence of CAV on heterogeneous traffic flow.This research contributes to providing theoretical guidance for future CAV applications,aiming to enhance urban road traffic effi
