Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric rout...Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.展开更多
This paper proposes an energy-efficient geocast algorithm for wireless sensor networks with guaranteed de-livery of packets from the sink to all nodes located in several geocast regions. Our approach is different from...This paper proposes an energy-efficient geocast algorithm for wireless sensor networks with guaranteed de-livery of packets from the sink to all nodes located in several geocast regions. Our approach is different from those existing in the literature. We first propose a hybrid clustering scheme: in the first phase we partition the network in cliques using an existing energy-efficient clustering protocol. Next the set of clusterheads of cliques are in their turn partitioned using an energy-efficient hierarchical clustering. Our approach to con-sume less energy falls into the category of energy-efficient clustering algorithm in which the clusterhead is located in the central area of the cluster. Since each cluster is a clique, each sensor is at one hop to the cluster head. This contributes to use less energy for transmission to and from the clusterhead, comparatively to multi hop clustering. Moreover we use the strategy of asleep-awake to minimize energy consumption during extra clique broadcasts.展开更多
Nowadays, both vehicular active safety service and user infotainment service have become two core applications for urban Vehicular Delay Tolerant Networks（u VDTNs）. Both core applications require a high data transmi...Nowadays, both vehicular active safety service and user infotainment service have become two core applications for urban Vehicular Delay Tolerant Networks（u VDTNs）. Both core applications require a high data transmission capacity over u VDTNs. In addition, the connection between any two vehicles in u VDTNs is intermittent and opportunistic. Intermittent data dissemination over u VDTNs is a stringent and challenging issue. In this paper,we propose Intermittent Geocast Routing（IGR）. For the first step, IGR has to estimate the active connection time interval via the moving directions and velocities between any two vehicles. Second, the throughput function for u VDTNs is fitted by building a wavelet neural network traffic model. Third, the throughput function within the effective connection time interval is integrated to obtain the forwarding capability estimation of the node. Fourth, a high-efficiency geocast routing algorithm using the node forwarding capability for u VDTNs is designed. Finally, IGR is simulated on the opportunistic Network Environment simulator. Experimental results show that IGR can greatly improve the packet delivery ratio, transmission delay, delay jitter, and packet loss rate compared with the state of the art.展开更多
基于地理位置的路由协议因其对动态拓扑的高适应能力已成为车载自组织网(Vehicular Ad Hoc Network,VANET)的主导路由协议。首先,介绍基于地理位置的路由协议的基本思想,描述几种经典的基于地理位置的单播和多播路由协议算法。其次,分析...基于地理位置的路由协议因其对动态拓扑的高适应能力已成为车载自组织网(Vehicular Ad Hoc Network,VANET)的主导路由协议。首先,介绍基于地理位置的路由协议的基本思想,描述几种经典的基于地理位置的单播和多播路由协议算法。其次,分析VANET的特点,基于此对VANET环境中基于地理位置的单播和多播路由协议进行分析总结。再次,介绍欧洲电信标准化协会提出的面向VANET的基于地理位置路由的协议标准GeoNetworking的基本实现框架。最后,对VANET中基于地理位置的路由协议存在的问题进行分析总结,指出未来的研究方向及挑战。展开更多
车载网(vehicular ad hoc networks,VANETs)是由高速移动的车辆构成、自组织分布的无线网络。部署VANETs的目的之一在于提高交通安全、减少交通堵塞,特别是有利于安全消息的传播。然而,城市环境中安全消息的分发受道路结构、红绿灯等因...车载网(vehicular ad hoc networks,VANETs)是由高速移动的车辆构成、自组织分布的无线网络。部署VANETs的目的之一在于提高交通安全、减少交通堵塞,特别是有利于安全消息的传播。然而,城市环境中安全消息的分发受道路结构、红绿灯等因素影响。为此,针对城市环境安全消息的传输问题,提出基于交通灯的时间稳定组播VANETs路由机制T-TSG(traffic light based time stable geocast)。T-TSG依据交通灯的不同情况,确定区播区域(geocast region,GR)、区播消息稳定区域(geocast message stable region,GMSR)以及稳定车辆区域(stable vehicle region,SVR)。仿真表明,提出的路由协议在数据传输率、端到端传输时延、网络开销方面得到提升。展开更多
车联网VANETs(Vehicular Ad Hoc Networks)是传统自组织网络派生的一个子类,具有鲜明的特性。传统的地域性多播协议不能有效地适用于车联网。为此,提出了基于单播和无比率编码的地域性多播路由(Unicast and Rateless Coding Based Geoca...车联网VANETs(Vehicular Ad Hoc Networks)是传统自组织网络派生的一个子类,具有鲜明的特性。传统的地域性多播协议不能有效地适用于车联网。为此,提出了基于单播和无比率编码的地域性多播路由(Unicast and Rateless Coding Based Geocast Routing,URC-GR)协议。URC-GR协议引用两个策略解决传统地域性多播路由协议在开销和数据包传递率方面的不足。首先,利用单播机制向目标区域传输数据,然后,在目标区域内再泛洪。其次,利用无比率编码提高数据传输率。最后,将提出的URC-GR协议与IVG(Inter Vehicle Geocast)、DRG(Distributed Robust Geocast)协议进行比较,仿真结果表明,URC-GR协议能够有效地降低开销和提高数据包传输率。展开更多
文摘Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.
文摘This paper proposes an energy-efficient geocast algorithm for wireless sensor networks with guaranteed de-livery of packets from the sink to all nodes located in several geocast regions. Our approach is different from those existing in the literature. We first propose a hybrid clustering scheme: in the first phase we partition the network in cliques using an existing energy-efficient clustering protocol. Next the set of clusterheads of cliques are in their turn partitioned using an energy-efficient hierarchical clustering. Our approach to con-sume less energy falls into the category of energy-efficient clustering algorithm in which the clusterhead is located in the central area of the cluster. Since each cluster is a clique, each sensor is at one hop to the cluster head. This contributes to use less energy for transmission to and from the clusterhead, comparatively to multi hop clustering. Moreover we use the strategy of asleep-awake to minimize energy consumption during extra clique broadcasts.
基金partially supported by the National Natural Science Foundation of China(Nos.61202474,61272074,61373017,and 61572260)the Project Funded by China Postdoctoral Science Foundation(No.2015M570469)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20130528)the Key Research and Development Program(Social Development)Foundation of Zhenjiang(No.SH2015020)the Senior Professional Scientific Research Foundation of Jiangsu University(No.12JDG049)
文摘Nowadays, both vehicular active safety service and user infotainment service have become two core applications for urban Vehicular Delay Tolerant Networks（u VDTNs）. Both core applications require a high data transmission capacity over u VDTNs. In addition, the connection between any two vehicles in u VDTNs is intermittent and opportunistic. Intermittent data dissemination over u VDTNs is a stringent and challenging issue. In this paper,we propose Intermittent Geocast Routing（IGR）. For the first step, IGR has to estimate the active connection time interval via the moving directions and velocities between any two vehicles. Second, the throughput function for u VDTNs is fitted by building a wavelet neural network traffic model. Third, the throughput function within the effective connection time interval is integrated to obtain the forwarding capability estimation of the node. Fourth, a high-efficiency geocast routing algorithm using the node forwarding capability for u VDTNs is designed. Finally, IGR is simulated on the opportunistic Network Environment simulator. Experimental results show that IGR can greatly improve the packet delivery ratio, transmission delay, delay jitter, and packet loss rate compared with the state of the art.
文摘基于地理位置的路由协议因其对动态拓扑的高适应能力已成为车载自组织网(Vehicular Ad Hoc Network,VANET)的主导路由协议。首先,介绍基于地理位置的路由协议的基本思想,描述几种经典的基于地理位置的单播和多播路由协议算法。其次,分析VANET的特点,基于此对VANET环境中基于地理位置的单播和多播路由协议进行分析总结。再次,介绍欧洲电信标准化协会提出的面向VANET的基于地理位置路由的协议标准GeoNetworking的基本实现框架。最后,对VANET中基于地理位置的路由协议存在的问题进行分析总结,指出未来的研究方向及挑战。
文摘车载网(vehicular ad hoc networks,VANETs)是由高速移动的车辆构成、自组织分布的无线网络。部署VANETs的目的之一在于提高交通安全、减少交通堵塞,特别是有利于安全消息的传播。然而,城市环境中安全消息的分发受道路结构、红绿灯等因素影响。为此,针对城市环境安全消息的传输问题,提出基于交通灯的时间稳定组播VANETs路由机制T-TSG(traffic light based time stable geocast)。T-TSG依据交通灯的不同情况,确定区播区域(geocast region,GR)、区播消息稳定区域(geocast message stable region,GMSR)以及稳定车辆区域(stable vehicle region,SVR)。仿真表明,提出的路由协议在数据传输率、端到端传输时延、网络开销方面得到提升。
文摘车联网VANETs(Vehicular Ad Hoc Networks)是传统自组织网络派生的一个子类,具有鲜明的特性。传统的地域性多播协议不能有效地适用于车联网。为此,提出了基于单播和无比率编码的地域性多播路由(Unicast and Rateless Coding Based Geocast Routing,URC-GR)协议。URC-GR协议引用两个策略解决传统地域性多播路由协议在开销和数据包传递率方面的不足。首先,利用单播机制向目标区域传输数据,然后,在目标区域内再泛洪。其次,利用无比率编码提高数据传输率。最后,将提出的URC-GR协议与IVG(Inter Vehicle Geocast)、DRG(Distributed Robust Geocast)协议进行比较,仿真结果表明,URC-GR协议能够有效地降低开销和提高数据包传输率。
