共查询到19条相似文献,搜索用时 93 毫秒
1.
为了深入研究分布式认知无线电网络的多路径路由问题,阐述了分布式认知无线电网络基本特征以及多路径路由设计面临的问题与挑战。分布式认知无线电网络多路径路由采用多路径并行传输,可有效降低传输时延、增加网络吞吐量与传输可靠性、实现网络负载均衡。根据路由优化目标不同,从吞吐量、带宽、干扰、时延、负载均衡和路由发现六方面对近年来多路径路由协议的主要研究成果进行了分类,然后逐类对多路径路由协议进行了分析和讨论,最后分别从分布式认知无线电网络基本特征的适应性与多路径路由协议特征两个方面进行了比较,并展望了分布式认知无线电网络多路径路由协议需进一步研究的方向。 相似文献
2.
3.
针对认知无线电网络中传统路由可靠性较低的问题,提出了一种改进的可靠信道路由算法(Improved reliable channel routing,IRCR)。算法根据认知无线电网络频谱的动态性,利用相邻节点间信道利用率,选择可靠邻节点,并根据可靠邻节点建立可靠路由。仿真结果表明,与传统频谱感知按需路由协议(spectrumaware on-demand routing protocol,SORP)相比,IRCR具有较高的数据包投递率和较低平均时延。 相似文献
4.
5.
在认知无线电中,网络层用于确定如何在网络中找到一条从源节点到目标节点的路径,且数据路径应当是适应频谱状况的,即尽可能绕过主用户频繁出现的区域。由于频谱是随机的,因而数据路径也可能是随机的。文章分析认知无线电网络中路由面临的挑战,介绍认知无线电网络中的两种路由方案:静态路由和动态路由,给出静态路由频谱选择阶段的5个指标,研究静态路由下一跳选择阶段的优化问题,最后提出认知无线电网络动态路由的实现方案。 相似文献
6.
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
7.
8.
9.
认知无线电网络诱骗攻击问题及安全解决方案 总被引:3,自引:0,他引:3
针对认知无线电网络可用频谱动态变化的特点,提出一种特有的诱骗攻击问题,即在分布式认知无线电网络中,当认知节点采用按需路由协议建立路由链接时,恶意节点向路由请求数据包中加入虚假频谱信息,诱使其他节点建立路由链接,随后丢弃需其转发的数据包.为了解决这个问题,将认知无线电网络分成单跳有簇头结构,通过簇头检测恶意节点.为便于检验方案的可行性,结合簇头检测结果设计了一种路由协议.理论分析和仿真实验表明该安全问题会显著降低网络通信性能,本文提出的解决方案是有效和可行的. 相似文献
10.
针对认知无线电网络可用信道资源随时间和空间环境变化的特点,分析了认知无线电网络MAC协议面临的问题,提出了一种基于全局控制信道的MAC协议方案,在此基础上阐述了两种接入方式及相应适用场合,实现了认知无线电节点对可用信道资源变化的感知,可为认知无线电MAC协议研究及应用提供参考. 相似文献
11.
Kwang‐Cheng Chen Bilge Kartal Cetin Yu‐Cheng Peng Neeli Prasad Jin Wang Songyoung Lee 《Wireless Communications and Mobile Computing》2010,10(4):451-466
Cognitive radio (CR) has been considered a key technology to enhance overall spectrum utilization by opportunistic transmissions in CR transmitter–receiver link(s). However, CRs must form a cognitive radio network (CRN) so that the messages can be forwarded from source to destination, on top of a number of opportunistic links from co‐existing multi‐radio systems. Unfortunately, appropriate routing in CRN of coexisting multi‐radio systems remains an open problem. We explore the fundamental behaviors of CR links to conclude three major challenges, and thus decompose general CRN into cognitive radio relay network (CRRN), CR uplink relay network, CR downlink relay network, and tunneling (or core) network. Due to extremely dynamic nature of CR links, traditional routing to maintain end‐to‐end routing table for ad hoc networks is not feasible. We locally build up one‐step forward table at each CR to proceed based on spectrum sensing to determine trend of paths from source to destination, while primary systems (PSs) follow original ways to forward packets like tunneling. From simulations over ad hoc with infrastructure network topology and random network topology, we demonstrate such simple routing concept known as CRN local on‐demand (CLOD) routing to be realistic at reasonable routing delay to route packets through. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
12.
认知无线网络中基于主用户行为的联合路由和信道分配算法 总被引:1,自引:0,他引:1
针对认知无线网络中主用户行为将导致频谱瞬时变化而影响路由稳定性的问题,提出了一种基于主用户行为的路由和信道联合分配算法。该算法通过采用呼叫模型对主用户行为建模,并根据动态源路由协议的路由寻找机制,在目的节点等待多个路由请求分组后选择受主用户行为影响最小的路由,然后沿着所选定路径的反方向传送路由回复分组并完成信道分配。理论分析证明了算法中的链路平均持续时间期望与主用户活动概率成反比且具有与网络节点数成正比的计算复杂度。仿真结果表明,该算法具有比Gymkhana路由方案更高的分组投递率和更低的平均分组时延。 相似文献
13.
随着异构网络融合和网络自适应化逐渐成为必然的发展趋势,认知无线网络随之出现,并提供了一种实现全局端到端目标优化的方法。认知无线网络由能自适应改变自身配置的网络设备组合而成,为设计灵活高效的拓扑策略提供了可能性和保障。提出了一种拓扑重构的控制策略,能够规划数据传输路由,在高效利用空闲频谱资源的同时,提升了传输的效率和性能。 相似文献
14.
In this letter, a problem related to the behavior of WLAN 802.11 b network cards when working in the ad hoc mode is described. This behavior was noticed during experimental evaluation of an ad hoc network that was using the AODV (ad hoc On-demand Distance Vector) routing protocol. The observed problem affects the neighbor detection algorithm of the AODV routing protocol and has a deteriorating impact on performance of ad hoc networks that use this protocol. An improvement of the neighbor detection algorithm based on the differentiation of good and bad neighbors using signal to noise ratio (SNR) value is proposed, described and experimentally verified. 相似文献
15.
The authors present an algorithm for routing fiber around a ring in a network, when the network nodes, links, connectivity, and which offices are to be used on that ring together are known. The algorithm aids automated survivable network planning. The algorithm was programmed in C, and run on a SPARC-station. Under certain conditions, the problem degenerates to the traveling salesman problem, and the ring routing algorithm degenerates to the nearest neighbor method of solving that problem 相似文献
16.
Santosh Kumar Bharti Sharma Awadhesh Kumar Singh 《International Journal of Communication Systems》2020,33(8)
Numerous research articles exist for backbone formation in wireless networks; however, they cannot be applied straightforward in cognitive radio network (CRN) due to its peculiar characteristics. Since virtual backbone has many advantages such as reduced routing overhead, dynamic maintenance, and fast convergence speed, we intend to propose a backbone formation protocol in CRN. In this paper, we propose a tree‐based backbone formation protocol along with its maintenance. Our protocol is based on non‐iterative approach, thus leading towards limited message overhead and faster convergence speed. The proposed algorithm first forms the tree by maintaining the parent‐child relationship, and second, the parent nodes are connected together to form the virtual backbone. In the end, we evaluate the performance our protocol through extensive simulations. 相似文献
17.
18.
《Digital Communications & Networks》2017,3(2):129-139
Cognitive radio networks (CRN) are currently gaining immense recognition as the most-likely next-generation wireless communication paradigm, because of their enticing promise of mitigating the spectrum scarcity and/or underutilisation challenge. Indisputably, for this promise to ever materialise, CRN must of necessity devise appropriate mechanisms to judiciously allocate their rather scarce or limited resources (spectrum and others) among their numerous users. ‘Resource allocation (RA) in CRN', which essentially describes mechanisms that can effectively and optimally carry out such allocation, so as to achieve the utmost for the network, has therefore recently become an important research focus. However, in most research works on RA in CRN, a highly significant factor that describes a more realistic and practical consideration of CRN has been ignored (or only partially explored), i.e., the aspect of the heterogeneity of CRN. To address this important aspect, in this paper, RA models that incorporate the most essential concepts of heterogeneity, as applicable to CRN, are developed and the imports of such inclusion in the overall networking are investigated. Furthermore, to fully explore the relevance and implications of the various heterogeneous classifications to the RA formulations, weights are attached to the different classes and their effects on the network performance are studied. In solving the developed complex RA problems for heterogeneous CRN, a solution approach that examines and exploits the structure of the problem in achieving a less-complex reformulation, is extensively employed. This approach, as the results presented show, makes it possible to obtain optimal solutions to the rather difficult RA problems of heterogeneous CRN. 相似文献
19.
Jong‐Moon Chung Daeyoung Lee Jong‐Hong Park Kwangjae Lim HyunJae Kim Dong‐Seung Kwon 《ETRI Journal》2013,35(3):406-413
In this paper, an orthogonal frequency division multiple access (OFDMA)‐based minimum end‐to‐end delay (MED) distributed routing scheme for mobile backhaul wireless mesh networks is proposed. The proposed scheme selects routing paths based on OFDMA subcarrier synchronization control, subcarrier availability, and delay. In the proposed scheme, OFDMA is used to transmit frames between mesh routers using type‐I hybrid automatic repeat request over multipath Rayleigh fading channels. Compared with other distributed routing algorithms, such as most forward within radius R, farthest neighbor routing, nearest neighbor routing, and nearest with forwarding progress, simulation results show that the proposed MED routing can reduce end‐to‐end delay and support highly reliable routing using only local information of neighbor nodes. 相似文献