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1.
在Ad hoc网络(自组织网络)的路由建立过程中,由于AODV(Ad hoc按需距离矢量)路由采用洪泛方式转发RREQ(路由请求)消息会产生很多不必要的重传,很可能引发广播风暴而影响网络性能。文章提出了一种基于动态概率转发RREQ消息的改进方案,该方案根据邻居节点的个数选择不同的概率转发RREQ消息。仿真结果表明,在网络节点较多且网络比较稠密的情况下,改进方案能有效减少网络端到端时延,提高网络吞吐量和分组投递率。  相似文献   

2.
在机会网络中,节点之间可能不存在端到端的路径.为了节省网络中节点消耗的能量,在概率路由算法的基础上提出了一种基于节点能量的概率路由算法(Energy-based Probabilistic Routing Protocol using History of Encounters and Transitivity,EBPROPHET).首先,计算两个节点相遇时节点的通信开销,然后相遇节点的剩余能量作为一个参量引入算法,选择节点剩余能量多的节点作为转发节点,最后,进行消息的转发.仿真表明,EB-PROPHET算法具有良好的路由性能,降低了整个网络的能量消耗,延长了网络的生存周期.  相似文献   

3.
基于缓存旁路和本地修复的多跳网络路由重建机制   总被引:1,自引:0,他引:1  
该文针对多跳网络中现有AODV和AODV-BR按需路由算法的弊端,提出了基于缓存旁路和本地修复的AODV-CL路由重建机制.该机制利用空闲时间监听无线信道中传输的所有数据包和路由控制信令,用于维护有效的邻居节点列表及本地路由缓存,有效降低了周期性HELLO消息带来的信令负担,并增加了可用路由信息.中间节点在发现断链时,尝试采用局部修复,尽量避免由源节点广播RREQ消息发现路由.根据本地路由缓存及邻居节点的路由信息,实现了快速的路由发现及修复,能有效降低路由控制信令开销及丢包率.  相似文献   

4.
ad hoc网络中一种基于信任模型的机会路由算法   总被引:2,自引:0,他引:2  
王博  陈训逊 《通信学报》2013,34(9):92-104
由于ad hoc网络具有缺乏足够的物理保护、拓扑结构动态变化、采用分布式协作、节点的带宽和计算能力有限等特点,导致传统的路由安全机制不再适合ad hoc网络路由协议的设计。最近当前研究热点之一的机会路由能够在链路不可靠的情况下充分利用无线广播和空间多样性的特性提高网络的吞吐量。因此,考虑在机会路由中引入信任相似性概念设计信任机会路由,建立了基于节点信任度和最小成本的信任机会转发模型,提出了最小成本的机会路由算法MCOR,并对算法进行了理论上的分析和证明。最后采用仿真实验对该算法进行验证,又与经典机会路由协议ExOR以及其他经典的信任路由协议TAODV和Watchdog-DSR进行性能对比。仿真结果表明,MCOR算法能够防范恶意节点的攻击,在吞吐量、端到端时延、期望转发次数(ETX)和成本开销等方面都比其他3种协议表现出性能上的优势。  相似文献   

5.
王恩博  董振中 《电子技术》2010,37(11):64-66
移动Ad hoc网络中节点的移动性使得频繁的路由失效与路由发现,路由发现中的控制开销是影响路由性能的一个重要的因素。传统的按需路由协议多采用洪泛的方式进行路由发现,并选取最小跳数路由。每个中间节点盲目的转发收到的路由请求包,不仅没有考虑链路质量,而且会引起广播风暴问题。本文提出一种基于链路质量和拓扑质量的路由协议,该协议根据相邻节点之间剩余链路生存期作为链路质量指标,同时根据中间节点与"源-目的"节点连线的距离关系作为拓扑质量指标。结合两个指标设置转发概率,不仅能避免频繁的路径断开,而且限制了路由请求包的传播范围。模拟结果显示,本文提出的方法在显著地降低路由控制开销的同时,还能够提高分组投递率并降低端到端延迟,从而提高了路由性能。  相似文献   

6.
对AODV协议在不同MANET网络环境中的性能缺陷进行了研究,提出了节点闲时反向路由搜索机制和邻居节点路由监听学习机制,并进一步提出了优化的AODV路由协议O-AODV。利用O-AODV协议在MANET网络中产生多个局部路由,从而增加网络中的路由冗余度,提高路由发现的效率,加快故障路由的本地修复。仿真实验结果表明,O-AODV协议提高了分组投递率,降低了端到端延时,有效地减少了网络中的重路由开销,在大规模和拓扑变化快的网络环境中优于AODV协议。  相似文献   

7.
针对无线传感网络的安全路由,提出能效和安全多跳路由(ESMR)。ESMR路由通过密钥共享策略,提高路由防御恶意节点的性能。ESMR路由先依据节点的位置将网络划分不同区(Zone),在每个Zone内,依据邻居节点位置划分多个簇;然后,每个Zone的簇头向基站传输数据,并依据密钥共享策略对数据进行加密。仿真结果表明,相比于同类路由,提出的ESMR在网络寿命、吞吐量、能耗以及端到端时延方面的性能得到有效提高。  相似文献   

8.
在动态网络拓扑中,AODV协议通过数据源节点S泛洪广播RREQ消息请求到任意目标节点D的路由,而在无线体域网络中,只有一个sink目标节点,除最短跳数路由上的节点外,其他参与RREQ接收和转发的节点浪费了能量.提出了一种能量平衡的无线体域网络AODV多播路由发现协议,通过在节点广播的hello消息中增加到sink的最小跳数hops、到sink的下一跳节点next和节点本身是否具备转发能力isforward3个参数,只选择能到达sink节点的邻居节点参与转发RREQ消息,变广播为多播,有效地降低了路由发现的能量开销,并通过能量平衡延长了WBAN的使用寿命.性能分析与模拟实验表明,该协议在RREQ数量、数据传输率和能量消耗等方面优于相似协议EAAODV.  相似文献   

9.
任智  朱其政  付泽亮  周舟  周杨 《电讯技术》2023,63(10):1546-1552
优化链路状态路由(Optimized Link State Routing,OLSR)协议是一种先验式路由协议,网络中的所有节点通过周期性地发送控制消息来计算全网路由信息。在短波自组织网络中,节点周期性地发送控制消息会占据大量的信道资源,大幅增加网络的控制开销,浪费短波有限的带宽资源,导致网络通信性能急剧下降。其次,受到地形地貌、天线方向和接收性能的个体差异等影响,造成无线链路不稳定,导致网络中存在非对称链路,增加了通信端到端时延。为此,提出了一种低时延的短波自组网OLSR协议。该协议在执行MPR(Multipoint Relay)选择算法时综合考虑了节点的连接度和链路可靠性,在优化MPR节点个数的同时选择链路可靠性较大的节点作为MPR节点,在进行路由选择时能够利用网络中的非对称链路。仿真结果表明,该协议能优化数据包投递成功率、吞吐量、端到端时延和网络控制开销等性能指标。  相似文献   

10.
ZigBee网络混合路由算法(ZigBee Routing,ZBR)中将源节点和目的节点之间的最小跳数作为唯一的路由度量因素.但随着节点能量消耗以及节点的频繁移动,ZBR算法的这一特性会造成网络间歇性连接,从而导致网络性能下降.提出一种选择最优分组转发路径的ZigBee网络混合路由算法(Grey Relational Algorithm based ZBR,GRA-ZBR).GRA-ZBR算法在目的节点选择路径时引入灰色关联算法,综合考虑节点剩余能量、链路质量、节点剩余队列长度以及路径长度等因素.仿真结果表明,GRA-ZBR算法可以有效提高网络分组投递率,降低平均端到端时延.  相似文献   

11.
Traditional routing protocols send traffic along pre-determined paths and have been shown ineffective in coping with unreliable and unpredictable wireless medium which is caused by the multi-path fading. The most difference between the opportunistic routing and the traditional routing mechanism is that the opportunistic routing mechanism can use several lossy broadcast links to support reliable transmission. In this paper, an opportunistic routing mechanism for real-time voice service is proposed. This mechanism is based on the dynamic source routing (DSR) protocol with some modifications, the routing messages of DSR are used to construct the forwarder list, which guides the data packets forwarding process. The forwarder nodes have priorities to restrict the number of duplicated packets. Simultaneous flows can be supported well by our mechanism. Simulations show that our mechanism can effectively decrease the data packets transmission times and the amount of the control messages and reduce the end-to-end delay for real-time voice service, the quality of service can be supported well over the unstable wireless channel.  相似文献   

12.
Energy efficiency is a key design criterion for routing protocols in wireless sensor networks since sensor nodes are strongly constrained in terms of energy supply. Gradient-Based Routing (GBR) is a well known energy efficient routing protocol that is used in WSNs. However, there exist shortcomings in the GBR scheme such as: (1) sinks make use of flooding to broadcast interest messages which leads to a lot of duplication packets which are transmitted. This leads to the waste of a lot of energy in the network and (2) nodes deliver messages in a point to point manner. As a result, the potential of data retransmissions in the network is high due to the unstable network environment in WSNs. In this study, network coding and a competitive approach are proposed to solve the above two problems. Firstly, an energy efficient broadcast algorithm using network coding for GBR (GBR-NC) is proposed. This algorithm aims to reduce network traffic, and furthermore, reduce the energy consumption and prolong the lifetime of the network. Secondly, two competing algorithms (GBR-C and auto-adaptable GBR-C) are proposed for GBR. The basic idea of the proposed competing algorithms is to reduce the retransmission attempts and save the energy by considering two forward candidates. Simulation results show that the proposed schemes give better results when compared to the traditional GBR in terms of energy efficiency.  相似文献   

13.
Routing in delay tolerant networks (DTNs) is challenging due to their unique characteristics of intermittent node connectivity. Different protocols (single-, multi-copy, erasure-coding-based etc.) utilizing store-carry-and-forward paradigm have been proposed to achieve routing of messages in such environments by opportunistic message exchanges between nodes that are in the communication range of each other. The sparsity and distributed nature of these networks together with the lack of stable connectivity between source destination pairs make these networks vulnerable to malicious nodes which might attempt to learn the content of the messages being routed between the nodes. In this paper, we study DTNs in which malicious nodes are present, to which we refer to as compromised DTNs. We discuss and analyze the effects of presence of malicious nodes on routing of messages in compromised DTNs. We propose a two period routing approach which aims at achieving the desired delivery ratio by a given delivery deadline in presence of malicious nodes. Our simulation results with both random networks and real DTN traces show that, with proper parameter setting, the proposed method can achieve delivery ratios which surpass those reached by other algorithms by a given delivery deadline.  相似文献   

14.
徐婷  王新红  王平 《通信技术》2014,(2):163-166
本论文介绍了一种车联网中的多优先级的自适应动态路由协议(MPDAR),着重介绍了不同优先级等级消息的分发机制,该路由协议利用了车辆的地理位置和速度信息,并保证了1)车联网中不同类型消息具有不同的QoS要求;2)完全分布式路由协议。最后,本论文应用ViSSIM交通仿真软件和NS-2网络模拟软件,对MPDAR协议进行仿真。结果表明,MPDAR路由协议较其他路由协议性能有所改进。  相似文献   

15.
Delay Tolerant Networks (DTNs) provide message delivery services to users via intermittently connected nodes. In DTNs, routing is one of the most challenging issues since end-to-end connectivity between nodes may not be available most of the time. Although many routing protocols for DTNs have been proposed, they do not achieve satisfactory performance, since they exploit only some of the network characteristics. In this paper, we present a new DTN routing protocol, called the Link Contact Duration-based Routing Protocol (LCD). Like existing protocols, LCD uses the disconnect duration of a link between two nodes to find the routing path with the shortest end-to-end delay. In addition, LCD uses the contact duration of a link and the number of buffered messages to deliver as many messages as possible in a short time. Our simulation results show that LCD has better performance than existing DTN routing protocols.  相似文献   

16.
Information and communication technologies have changed the way of operations in all fields. These technologies also have adopted for wireless communication and provide low cost and convenient solutions. Vehicular ad hoc networks are envisioned with their special and unique intercommunication systems to provide safety in intelligent transportation systems and support large‐size networks. Due to dense and sparse traffic conditions, routing is always a challenging task to establish reliable and effective communication among vehicle nodes in the highly transportable environment. Several types of routing protocols have been proposed to handle high mobility and dynamic topologies including topology‐based routing, position and geocast routing, and cluster‐based routing protocols. Cluster‐based routing is one of the feasible solutions for vehicular networks due to its manageable and more viable nature. In cluster‐based protocols, the network is divided into many clusters and each cluster selects a cluster head for data dissemination. In this study, we investigate the current routing challenges and trend of cluster‐based routing protocols. In addition, we also proposed a Cluster‐based Routing for Sparse and Dense Networks to handle dynamic topologies, the high‐mobility of vehicle nodes. Simulation results show a significant performance improvement of the proposed protocol.  相似文献   

17.
无线传感网络(WSN)路由协议中,分簇路由具有拓扑管理方便、能量高效和数据融合简单等优点,成为当前重点研究的路由技术。通过研究各种环境下的移动传感器网络,有效地降低能耗则是研究移动无线传感器网络的重要目的之一。针对无线传感网络中移动性问题,基于LEACH协议,利用移动传感器网络中节点距离、速度和剩余能量等因素提出了能量高效的移动分簇路由算法。实验结果表明此算法能够较好地支持节点移动,从而降低网络能耗,延长网络生存时间。  相似文献   

18.
POSITION VERIFICATION APPROACHES FOR VEHICULAR AD HOC NETWORKS   总被引:1,自引:0,他引:1  
Intervehicle communication is regarded as one of the major applications of mobile ad hoc networks (MANETs). Compared to MANETs, these so-called vehicular ad hoc networks (VANETs) have special requirements in terms of node mobility and position-dependent applications, which are well met by geographic routing protocols. Functional research on geographic routing has already reached a considerable level, whereas security aspects have been vastly neglected so far. Since position dissemination is crucial for geographic routing, forged position information has severe impact regarding both performance and security. In this work, we first analyze the problems that may arise from falsified position data. Then, in order to lessen these problems, we propose detection mechanisms that are capable of recognizing nodes cheating about their location in position beacons. In contrast to other position verification approaches, our solution does not rely on special hardware or dedicated infrastructure. Evaluation based on simulations shows that our position verification system successfully discloses nodes disseminating false positions and thereby widely prevents attacks using position cheating  相似文献   

19.
In delay-tolerant mobile ad hoc networks, motion of network nodes, network sparsity and sporadic density can cause a lack of guaranteed connectivity. These networks experience significant link delay and their routing protocols must take a store-and-forward approach. In this paper, an opportunistic routing protocol is proposed, along with its compatible media access control, for non-real-time services in delay-tolerant networks. The scheme is mobility-aware such that each network node needs to know its own position and velocity. The media access control employs a four-fold handshake procedure to probe the wireless channel and cooperatively prioritize candidate nodes for packet replication. It exploits the broadcast characteristic of the wireless medium to utilize long-range but unreliable links. The routing process seizes opportunities of node contacts for data delivery. It takes a multiple-copy approach that is adaptive with node movements. Numerical results in mobile ad hoc networks and vehicular ad hoc networks show superior performance of the proposed protocol compared with other routing protocols. The mobility-aware media access control and routing scheme exhibits relatively small packet delivery delay and requires a modest amount of total packet replications/transmissions.  相似文献   

20.
A Vehicular Ad hoc Network is a type of wireless ad hoc network that facilitates ubiquitous connectivity between vehicles in the absence of fixed infrastructure. Source based geographical routing has been proven to perform well in unstable vehicular networks. However, these routing protocols leverage beacon messages to update the positional information of all direct neighbour nodes. As a result, high channel congestion or problems with outdated neighbour lists may occur. To this end, we propose a street-aware, Intelligent Beaconless (IB) geographical forwarding protocol based on modified 802.11 Request To Send (RTS)/ Clear To Send frames, for urban vehicular networks. That is, at the intersection, each candidate junction node leverage digital road maps as well as distance to destination, power signal strength of the RTS frame and direction routing metrics to determine if it should elect itself as a next relay node. For packet forwarding between Intersections, on the other hand, the candidate node considers the relative direction to the packet carrier node and power signal strength of the RTS frame as routing metrics to elect itself based on intelligently combined metrics. After designing the IB protocol, we implemented it and compared it with standard protocols. The simulation results show that the proposed protocol can improve average delay and successful packet delivery ratio in realistic wireless channel conditions and urban vehicular scenarios.  相似文献   

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