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
A Trunk Line Based Geographic Routing(TLBGR)protocol in Vehicular Ad-hoc Networks(VANETs)is proposed in this paper to solve the problem of data acquisition in the traditional trunk coordinated control system.Because o...A Trunk Line Based Geographic Routing(TLBGR)protocol in Vehicular Ad-hoc Networks(VANETs)is proposed in this paper to solve the problem of data acquisition in the traditional trunk coordinated control system.Because of the characteristics of short communication time and high packet loss among vehicles,the vehicles entering the trunk lines can not transmit their information to the trunk coordinated control system stably.To resolve this problem,the proposed protocol uses the trunk lines’traffic flow and the surrounding road network to provide a real-time data transmission routing scheme.It takes into account the data congestion problem caused by the large traffic flow of the main roads,which leads to the corresponding increase of the information flow of the section and the package loss,and the link partition problem caused by the insufficient traffic flow,which makes the vehicles have to carry and relay information thus increasing the transmission delay.The proposed TLBGR protocol can be divided into two stages:the next-intersection selection,and the next-hop selection in the chosen path between the current and next intersections.Simulation results show that,compared with other IoT routing protocols including Greedy Perimeter Stateless Routing(GPSR),Ad-hoc On Demand Vector(AODV),and Q-AODV,the TLBGR protocol has better performance in aspects of end-to-end delay,delivery rate,and routing cost under the scenario of urban traffic trunk lines.The TLBGR protocol can effectively avoid data congestion and local optimum problems,increase the delivery rate of data packets,and is therefore suitable for the routing requirements in this application scenario.展开更多
GoTaTM from ZTE is the world’s first CDMA-based system. Now, ZTE proudly introduces its third-generation digital trunking system featuring a centralized dispatch,
Go Tafrom ZTE is the world’s first CDMA-based system. Now, ZTE proudly introduces its third-generation digital trunking system featuring a centralized dispatch,
A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in ...A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in a coordinated way. Employing clustering techniques in such networks can achieve balanced energy consumption of member nodes and prolong the network lifetimes.In classical clustering techniques, clustering and in-cluster data routes are usually separated into independent operations. Although separate considerations of these two issues simplify the system design, it is often the non-optimal lifetime expectancy for wireless sensor networks. This paper proposes an integral framework that integrates these two correlated items in an interactive entirety. For that,we develop the clustering problems using nonlinear programming. Evolution process of clustering is provided in simulations. Results show that our joint-design proposal reaches the near optimal match between member nodes and cluster heads.展开更多
Target tracking is a typical and important application of wireless sensor networks(WSNs).Existing target tracking protocols focus mainly on energy efficiency,and little effort has been put into network management and ...Target tracking is a typical and important application of wireless sensor networks(WSNs).Existing target tracking protocols focus mainly on energy efficiency,and little effort has been put into network management and real-time data routing,which are also very important issues for target tracking.In this paper,we propose a scalable cluster-based target tracking framework,namely the hierarchical prediction strategy(HPS),for energyefficient and real-time target tracking in large-scale WSNs.HPS organizes sensor nodes into clusters by using suitable clustering protocols which are beneficial for network management and data routing.As a target moves in the network,cluster heads predict the target trajectory using Kalman filter and selectively activate the next round of sensors in advance to keep on tracking the target.The estimated locations of the target are routed to the base station via the backbone composed of the cluster heads.A soft handoff algorithm is proposed in HPS to guarantee smooth tracking of the target when the target moves from one cluster to another.Under the framework of HPS,we design and implement an energy-efficient target tracking system,HierTrack,which consists of 36 sensor motes,a sink node,and a base station.Both simulation and experimental results show the efficiency of our system.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.
基金supported by the National Key Research and Development Program of China(2018YFE0126000)the National Natural Science Foundation of China(62072360,61902292,62001357,62072359,62072355)+3 种基金the key research and development plan of Shaanxi province(2021ZDLGY02-09,2019ZDLGY13-07,2019ZDLGY13-04,2020JQ-844)the key laboratory of embedded system and service computing(Tongji University)(ESSCKF2019-05)Ministry of Education,the Xi'an Science and Technology Plan(20RGZN0005)the Xi'an Key Laboratory of Mobile Edge Computing and Security(201805052-ZD3CG36).
文摘A Trunk Line Based Geographic Routing(TLBGR)protocol in Vehicular Ad-hoc Networks(VANETs)is proposed in this paper to solve the problem of data acquisition in the traditional trunk coordinated control system.Because of the characteristics of short communication time and high packet loss among vehicles,the vehicles entering the trunk lines can not transmit their information to the trunk coordinated control system stably.To resolve this problem,the proposed protocol uses the trunk lines’traffic flow and the surrounding road network to provide a real-time data transmission routing scheme.It takes into account the data congestion problem caused by the large traffic flow of the main roads,which leads to the corresponding increase of the information flow of the section and the package loss,and the link partition problem caused by the insufficient traffic flow,which makes the vehicles have to carry and relay information thus increasing the transmission delay.The proposed TLBGR protocol can be divided into two stages:the next-intersection selection,and the next-hop selection in the chosen path between the current and next intersections.Simulation results show that,compared with other IoT routing protocols including Greedy Perimeter Stateless Routing(GPSR),Ad-hoc On Demand Vector(AODV),and Q-AODV,the TLBGR protocol has better performance in aspects of end-to-end delay,delivery rate,and routing cost under the scenario of urban traffic trunk lines.The TLBGR protocol can effectively avoid data congestion and local optimum problems,increase the delivery rate of data packets,and is therefore suitable for the routing requirements in this application scenario.
文摘GoTaTM from ZTE is the world’s first CDMA-based system. Now, ZTE proudly introduces its third-generation digital trunking system featuring a centralized dispatch,
文摘Go Tafrom ZTE is the world’s first CDMA-based system. Now, ZTE proudly introduces its third-generation digital trunking system featuring a centralized dispatch,
基金supported by National Natural Science Foundation of China(Nos.61304131 and 61402147)Grant of China Scholarship Council(No.201608130174)+2 种基金Natural Science Foundation of Hebei Province(Nos.F2016402054 and F2014402075)the Scientific Research Plan Projects of Hebei Education Department(Nos.BJ2014019,ZD2015087 and QN2015046)the Research Program of Talent Cultivation Project in Hebei Province(No.A2016002023)
文摘A heterogeneous wireless sensor network comprises a number of inexpensive energy constrained wireless sensor nodes which collect data from the sensing environment and transmit them toward the improved cluster head in a coordinated way. Employing clustering techniques in such networks can achieve balanced energy consumption of member nodes and prolong the network lifetimes.In classical clustering techniques, clustering and in-cluster data routes are usually separated into independent operations. Although separate considerations of these two issues simplify the system design, it is often the non-optimal lifetime expectancy for wireless sensor networks. This paper proposes an integral framework that integrates these two correlated items in an interactive entirety. For that,we develop the clustering problems using nonlinear programming. Evolution process of clustering is provided in simulations. Results show that our joint-design proposal reaches the near optimal match between member nodes and cluster heads.
基金Project supported by the National Natural Science Foundation of China(No.61273079)the State Key Laboratory of Industrial Control Technology(Nos.ICT1206 and ICT1207)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDA06020300)the Key Laboratory of Wireless Sensor Network & Communication of Chinese Academy of Sciences (No.2011001)
文摘Target tracking is a typical and important application of wireless sensor networks(WSNs).Existing target tracking protocols focus mainly on energy efficiency,and little effort has been put into network management and real-time data routing,which are also very important issues for target tracking.In this paper,we propose a scalable cluster-based target tracking framework,namely the hierarchical prediction strategy(HPS),for energyefficient and real-time target tracking in large-scale WSNs.HPS organizes sensor nodes into clusters by using suitable clustering protocols which are beneficial for network management and data routing.As a target moves in the network,cluster heads predict the target trajectory using Kalman filter and selectively activate the next round of sensors in advance to keep on tracking the target.The estimated locations of the target are routed to the base station via the backbone composed of the cluster heads.A soft handoff algorithm is proposed in HPS to guarantee smooth tracking of the target when the target moves from one cluster to another.Under the framework of HPS,we design and implement an energy-efficient target tracking system,HierTrack,which consists of 36 sensor motes,a sink node,and a base station.Both simulation and experimental results show the efficiency of our system.
