无人机辅助车联网的网络传输链路优化

无人机(UAV)通信技术的快速发展与智能车联网应用需求的极速增长促进了无人机辅助车联网系统的产生与发展。在无人机辅助车联网系统中,如何节省能量的同时最大化系统性能对于能量有限的节点十分重要。基于此,本文主要考虑无人机辅助车联网通信过程中如何选择最优的通信网络链路,从而最大化能量效率的问题。首先建立通信网络链路选择问题为混合整数规划问题,然后提出基于能量效率最大化的网络传输链路优化算法获得最优的传输链路及对应的能量分配,最后通过数值实验仿真验证了所提算法的有效性。     

一维车载Ad Hoc网络连接度分析

In this paper we analyze connectivity of one-dimensional Vehicular Ad Hoc Networks where vehicle gap distribution can be approximated by an exponential distribution. The probabilities of Vehicular Ad Hoc Network connectivity for difference cases are derived. Furthermore we proof that the nodes in a sub-interval [z1,z1 +Δz] of interval [0, z], z>0 where all the nodes are independently uniform distributed is a Poisson process and the relationship of Vehicle Ad hoc Networks and one-dimensional Ad Hoc networks ...     

Zigbee路由协议在VANET监控系统中的应用分析

本文以VANET的应用需求为出发点,提出一种基于双层拓扑结构的网络模型,并使用Network Simulator 2．0版软件完成了模型仿真,分析了簇树、AODVjr以及ZBR三种路由协议在相同车联网环境下的性能表现。最终表明,ZBR路由协议能够在确保较短时延以及较高分组递交率的条件下,很好地实现网络开销的降低。     

车载网络中的数据分发策略

通过车载网络(VAETNs)能够有效提高交通管理系统(TMS)的数据传输.然而,由于通信距离短以及车辆的移动,完成VANETs中的数据传输是一项挑战任务.为此,提出基于复杂网络指标的数据传输(MCDD)策略.MCDD策略依据二跳邻居的信息,并通过介数中心性和度中心性两项性能指标选择转发节点,进而降低开销和缩短传输时延....     

车联网环境下基于Cuckoo过滤器的轻量V2I认证算法

基于假名认证机制是保护车与路边设施间通信(V2I)隐私的有效方法,传统的基于证书撤销清单(CRL)方法存在通信和计算开销大的问题。为此,提出基于布谷鸟(Cuckoo)过滤器的轻量V2I认证算法(CFLA)。CFLA算法通过局部信任中心(LTA)给其覆盖内的车辆分配假名,并利用Merkle散列树(MHT)存储车辆假名,每辆车维持一棵独立MHT。同时,采用布谷鸟过滤器(CF)数据结构,降低存储、计算和通信开销。安全性能分析表明,提出的CFLA算法能够具有防御中间攻击、重放攻击的能力。相比于相关的同类算法,CFLA算法降低了认证开销。     

基于车流量感知的交叉口车速控制策略

通过车联网(VANETs)协同控制车速和交通灯是智能交通系统的核心技术一。提出基于VANETs交通灯的车速控制优化(VSCO)方案,通过VANETs对交通信号灯进行时间优化,并对行驶经过交通信号灯的车辆进行规划,进而降低交叉口黄灯困境(YLD)相关的事故,减少CO2排放以及车辆的等待时间。实验数据表明,相比于传统的固定时间交通灯机制,VSCO方案减少了车辆等待时间和燃油排放。     

Ad Hoc网络技术研究进展

AdHoc网络现在是非常有吸引力的研究方向。本文介绍了Ad Hoc网络的定义、特点、体系结构、信道接入协议，最后分析了Ad Hoc网络面临的问题。希望本文能为进行AdHoc网络技术研究的人们提供一定的方便。     

车载自组网中一种分布式自适应TDMA时隙分配策略

提出了一种适用于车载自组网的自适应TDMA时隙分配机制DATS,DATS利用节点的差异性优化TDMA时隙分配机制,并且能根据节点密度自适应地调节时隙分配比例。理论分析和实验结果表明,DATS时隙分配策略能提高节点竞争成功率,降低接入时延;与现有的几种协议相比能减少至少50%的节点冲突,且具有良好的可扩展性,能够适应局部节点密度的变化。     

美军TTNT数据链发展应用现状

TTNT数据链是一种基于IP的航空Ad hoc网络,是美军正在研制的新型先进武器协同级数据链。本文简要阐述了TTNT数据链的基本情况、技术特点、性能指标,回顾了它的发展历程,抛砖引玉地分析了其中主要关键技术,其MAC协议、路由协议和物理终端电台的设计紧紧围绕着打击\"时敏目标\"的要求展开,旨在实现空-空和空-地低时延网络通信。     

一种大规模组网路由算法设计

本文主要描述了一种大规模组网路由协议的算法设计,该路由协议为了减小网络协议开销采用分级架构、多点中继转发技术(Multipoint Relay,MPR)及可变周期发送拓扑消息等技术。本文最后对分层最优化链路状态路由协议(Hierarchical Optimized Link State Routing,HOLSR)算法的性能进行仿真分析。     

基于路径稳定性的Ad Hoc网络按需路由算法设计

鉴于Ad Hoc网络的高移动性,选择一条稳定的路径进行通信尤为重要.文章借鉴AODV按需路由的思想,提出了基于路径稳定性的路由算法PSR(Path Stable based on-demand Routing),通过引入路径有效因子PEF(Path Efficieney Factor)来考虑可行路径的稳定性问题,增强了所选路径的稳定性,减少了由于节点运动引起的链路断裂次数.性能分析和仿真结果表明,与AODV相比,PSR减少了开销,提高了效率,使得算法的性能得到了提升.     

Performance Study of Proactive Flow Handoff for Mobile Ad Hoc Networks

A Mobile Ad hoc Network (MANET) is a collection of wireless mobile computers forming a temporary network without any existing wire line infrastructure. Searching for feasible paths, or routing, is very challenging in mobile ad hoc networks because of frequent topology changes caused by users' mobility. Location information is required by some applications and can be used to facilitate routing implementation. In this paper, we propose a proactive flow handoff method based on nodes' location information. In summary, location information is utilised to reduce the control overhead in route discovery phase, to search quickly for a feasible path upon link breakage, and to hand off a flow to a stable path if the active one breaks based on predication. Keeping “always-on” end-to-end connectivity once a flow is established is the main advantage of this routing method. A thorough simulation study is performed to demonstrate the efficiency of this method. This research was supported by a grant from the Canadian Institute for Telecommunications Research under the NCE program of the Government of Canada. Kui Wu received his Ph.D in Computing Science from the University of Alberta, Canada, in 2002. He joined the Department of Computer Science at the University of Victoria, Canada in the same year and is currently an Assistant Professor there. His research interests include mobile and wireless networks, network performance evaluation, and network security. Janelle Harms received her Ph.D. in Computer Science from the University of Waterloo, Ontario, Canada working in the area of performance analysis of resource allocation mechanisms. She joined the Department of Computing Science at the University of Alberta in 1991 and is currently an Associate Professor there. Her research interests include performance aspects of network resource allocation, routing and design problems.     

Energy-Aware Interoperability of Manet and 4g Ran Routing

The requirements for telecommunication at 2012 are estimated to be on such demanding level that the 3G technologies will not be sufficient. It is unlikely that the 3G Radio Access Network (RAN) would scale up i.e., Fourth Generation (4G) RAN will need to be developed. The requirements for 4G are demanding and the level of uncertainty is high. The novel ad hoc networking technologies could provide flexible solutions for the 4G RAN and extend the operator radio coverage. Combining these differing communication technologies provides insight for the 4G RAN design. This paper analyses the Mobile Ad hoc Networks (MANET) requirements against the 4G requirements in terms of energy conservation. We find that there is mismatch between these two sets of requirements. Nevertheless, we demonstrate how these two approaches could co-exist in a mutually beneficial way. Finally, we propose interoperability requirements for MANET and 4G routing from the perspective of energy conservation. Harri Paloheimo is a researcher in Networking Technologies Laboratory at Nokia Research Center, Helsinki. In addition, he is a post graduate student in Telecommunications Software and Multimedia Laboratory, Department of Computer Science and Engineering, Helsinki University of Technology. He received M.Sc. degree majoring in space technology from Department of Electrical and Communications Engineering, Helsinki University of Technology in 2000. He currently works on next generation wireless networks with special interest in hybrid and relay networking solutions. Sudhir Dixit is currently a Nokia Research Fellow and works on next generation wireless networks. From 1996 to 2003 he was a Senior Research Manager, focusing on IP/ATM, wireless, content networks, and optical networks. Prior to that he worked at NYNEX Science & Technology (now Verizon), GTE (now Verizon), Codex Motorola, Wang, Harris, and STL (now Nortel Europe Labs). He has published or presented over 150 papers, published three books, and holds 14 patents. He is on the Editorial Board of the IEEE Communications Magazine, Springer's Wireless Personal Communications Journal, and KIC's Journal of Communications and Networks. He received a B.E. degree from MANIT, Bhopal, India, an M.E. degree from BITS, Pilani, India, a Ph.D. degree from the University of Strathclyde, Glasgow, Scotland, and an M.B.A. degree from Florida Institute of Technology, Melbourne. He is a Fellow of IEE (UK) and IETE (India). He represents Nokia on the Steering Board of the Wireless World Research Forum, and is also Vice Chair of the SIG on Self-Organization of Wireless World Systems. Dr.Tech. Antti Ylä-Jääski is a Professor of Telecommunications Software, Telecommunications Software and Multimedia Laboratory, Department of Computer Science and Engineering, Helsinki University of Technology. He is also a Research Fellow in Network Technologies Laboratory, Nokia Research Center, Helsinki. Prof Dr.Tech. Antti Ylä-Jääski received his PhD in ETH Zuerich 1993. Antti has worked with Nokia 1994–2004 in several research management positions with focus on future Internet technologies, mobile networks, applications, services, service management and service architectures. He has published about 30 articles and he holds several approved patents. Antti's current research interests include mobile networking, heterogeneous network environments, services, service architectures, service management and security issues.     

利用智能天线实现多点中继功能的Ad Hoc网络MAC协议

在Ad Hoc网络中,采用多跳传输来提高数据传输的质量以及速率。传统的单中继节点已经不能适应迅速增大的数据量以及节点的移动造成的信道衰落情况,所以本文提出了基于智能天线实现多点中继的MAC协议,该协议采用了智能天线实现了菱形握手机制,使数据实现同步传输。其次采用空时编码的协作机制,通过估计源信号来防止中继节点与目的节点信道衰落的情况。最后利用Busy Tones解决了隐藏终端和暴露终端的问题。通过仿真与比较证明MRDMAC协议在数据延时和通过率等各个方面都有很大的优越性。     

数字集群系统的Ad Hoc路由技术

介绍了传统数字集群系统在网络覆盖能力中的问题,通过研究Ad Hoc路由协议,分析了如何在数字集群系统中应用Ad Hoc的路由技术来提高系统性能,并提出了相应的网络体系结构和路由算法,针对新方案暴露出的QoS性能下降的问题,提出了两种分布式时延保证方案。该方案可以有效提高系统的灵活性,扩大网络的覆盖范围,提高服务质量。     

一种基于移动网络的端到端认证机制

为基于移动网络的业务通信双方-业务签约者和业务提供者之间建立一种端到端的相互信任关系,提出了一种新的基于移动网络的应用服务端到端认证机制。研究了移动网络业务通信的发展趋势和安全威胁,介绍了3GPP中的通用鉴权框架的认证机理,指出了它的不足,并且提出了改进方法。介绍了端到端认证机制的总体框架和协议流程,并对其安全性、通用性、灵活性进行了分析。给出了该认证机制的应用场景。     

无线Ad Hoc网络中的QoS路由协议

无线Ad Hoc网络的应用环境以及与Internet的互连都要求其必须提供一定的服务质量(QoS)保证,QoS路由技术是在无线Ad Hoc网络中实现QoS的重要方法。本文对近年来国内外在无线Ad Hoc网络中的QoS路由技术方面取得的研究成果进行了全面的概括总结和分类,对资源预留路由、多径路由和跨层优化路由3类QoS路由协议进行比较分析,并且提出了QoS路由技术亟待解决的问题和今后的发展方向。     

基于嵌入式实验床(Testbed)的AODV协议研究

AODV协议是一种用于无线Ad Hoc网络的路由协议.笔者在Linux操作系统下实现了AODV路由协议,并以此为基础,搭建了一个无线Ad hoc网络的实验床(Testbed),并成功移植到以PowerPC处理器为核心的嵌入式平台上.在实验床的真实场景中,本文从路由性能的三个方面端到端的延迟、吞吐量、投递率对AODV路由协议进行了一系列实验和性能评价工作,并分析了Hello消息机制对网络性能的影响.在实验床的基础上,本文设计实现了嵌入式视频采集传输实验、异网互联实验与网络拓扑图形化显示实验.