共查询到20条相似文献,搜索用时 187 毫秒
1.
2.
本文针对如何改善无线多跳Mesh网络的服务质量,满足无线多媒体业务对数据传输的带宽、时延、抖动的要求等问题,研究了一种基于无线信道状态和链路质量统计的MAC层最大重传次数的自适应调整算法。该算法通过对无线Mesh网络的无线信道环境的动态感知,利用分层判断法区分无线分组丢失的主要原因是无线差错还是网络拥塞导致,实时调整MAC层的最佳重传次数,降低无线网络中的分组冲突概率。基于链路状态信息的统计和最大重传策略,提出了一种启发式的基于环境感知的QoS路由优化机制HEAOR。该算法通过动态感知底层链路状态信息,利用灰色关联分析法自适应选择最优路径,在不增加系统复杂度的基础上,减少链路误判概率,提高传输效率。NS2仿真结果表明,HEAOR算法能有效减少重路由次数,降低链路失效概率,提高网络的平均吞吐率。本文提出的方法不仅能够优化MAC层的重传,而且通过发现跨层设计的优化参数实现对路径的优化选择。 相似文献
3.
多信道无线 Mesh 网络可以有效解决在多跳无线网络中容量下降的问题。然而现有的路由协议大部分为单信道的多跳无线网络所设计,对于多信道 WMN 而言,会导致无效的路由路径。分析了现有无线 Mesh 网络的路由算法,详细讨论了基于 WCETT (Weighted Cumulative Expected Transmission Time)的两种路由度量,在此基础上提出了一种新的路由量度 WCETTR-LB,其对链路信道干扰的估算更加精确,能够感知周围链路对本信道的潜在干扰,并且考虑了节点负载度的概念,更加有助于实现负载均衡。 相似文献
4.
一种基于改进蚁群算法的选播路由算法 总被引:4,自引:0,他引:4
为了在网络负载较大的情况下实现多目标多路径的选播路由,该文根据蚂蚁寻径与选播路由的相似性,提出了一种基于改进蚁群算法的选播路由算法。在运用数据包传输的历史信息来模拟路径信息素的基础上,增加了目标地址泛洪负载信息来模拟食物气味散发的过程,使得各个节点可以获得服务器和链路的最新信息。节点根据路径上的信息素、食物的气味以及链路的可见度等综合生成概率表,作为后继蚂蚁路径选择的依据。运用NS-2对该算法进行仿真,测试结果表明它可以减少传输时延,降低服务器负载的波动幅度,实现链路的负载均衡,增加网络的容量,提高选播服务的可扩展性。 相似文献
5.
在移动自组织网络中,相对于单路径路由算法而言,多路径路由算法可以均衡网络负载、提高路由的可靠性。通过对AOMDV路由协议进行改进,提出了基于能量感知和链路稳定度的多径MANET路由协议ELMRP。ELMRP协议综合考虑了节点的剩余能量和链路稳定度,根据路径的剩余能量和稳定度计算代价值,按照代价值在多条节点不相交路径上分配数据流量。仿真结果表明,和AOMDV路由协议相比,ELMRP协议延长了网络的生存时间,提高了数据分组递送率,降低了路由发现频度。 相似文献
6.
7.
针对虚拟环境下底层网络中光纤的概率性故障,传统的100%保护至少需要配置一条保护路径,造成资源冗余度高和虚拟网络请求接受率低的问题,该文提出一种基于安全性感知的差异化虚拟光网络的映射(SA-DVNM)策略,在链路发生故障时为差异化虚拟网络请求提供安全保证。在SA-DVNM策略中,设计了一个综合考虑物理节点对之间跳数和相邻带宽大小的节点权重式避免链路映射过长,并提出路径频谱资源使用均衡的链路映射机制,最小化瓶颈链路的数量。当单路径传输失败时,SA-DVNM策略设计允许路径分割的资源分配机制,为保障时延敏感业务的安全性,SA-DVNM策略在路由选择中设计了基于时延差优化的多路径路由频谱分配方法。仿真结果表明该文所提策略在概率故障环境中能够降低带宽阻塞率,提高频谱资源利用率和虚拟光网络接受率。 相似文献
8.
光突发交换网络中一种基于负载平衡的路由机制 总被引:2,自引:1,他引:1
光突发交换(OBS)是实现下一代光互联网技术中的一种极具前景的方案.OBS网络中采用的路由机制多是最短路径优先的路由选择机制,这种路由机制本身的缺陷会使网络有较大的阻塞概率,不能实时反映网络流量的变化,同时对不同的网络拓扑的适应性较差.本文提出了一种OBS网络中能实现负载平衡的路由机制,对一个请求选择一条可以使网络中各链路使用波长数的统计方差最小的路由.仿真结果表明,该方法在阻塞概率方面要优于最短路径路由机制;而在传输延迟性能方面接近于最短路径路由机制,同时对于不同的网络拓扑以及节点流量的变化都具有一定的适应性. 相似文献
9.
10.
提出一种增添能最有效减弱网络社团特性的边以提高Internet网络传输性能的策略,即减弱社团结构策略(简称WCS策略),并基于光逻辑链路可以提供与实际物理链路相当的高性能,以实现WCS策略的Internet网络的拓扑重构。在伪随机网络、具有社团结构的无标度人工网络和实际Internet网络上分别进行了基于全局最短路径路由和局部路由的实验。实验结果表明,利用WCS策略在社团之间少量边的添加,就能实现网络负载能力和平均最短路径的大幅改善。 相似文献
11.
Yunhui Zhou Fuchun Sun Bo Zhang 《International Journal of Satellite Communications and Networking》2007,25(6):603-617
The rapid advance of communication and satellite technology pushes broadband satellite networks to carry on multimedia traffic. However, the function of onboard routing cannot be provided in existing satellite networks with inter‐satellite links, and quality of service (QoS) of satellite networks cannot be reliably guaranteed because of great difficulties in processing of long distance‐dependent traffic. In this paper, a two‐layered low‐Earth orbit and medium‐Earth orbit satellite network (LMSN) is presented. A novel hierarchical and distributed QoS routing protocol (HDRP) is investigated, and an adaptive bandwidth‐constrained minimum‐delay path algorithm is developed to calculate routing tables efficiently using the QoS metric information composed of delays and bandwidth. The performance of LMSN and HDRP is also evaluated through simulations and theoretical analysis. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
12.
In low earth orbit(LEO) satellite networks,in view of the unbalanced link resource,it's difficult to meet differentiated quality of service(QoS) requirements and easily lead to reduce the efficiency of the whole network.A routing algorithm based on multi-objective decision making was proposed which defined LEO satellite network transmission service as the delay sensitive,sensitive bandwidth and reliability sensitive three categories.It used the eigenvector method to calculate service weights,and used the consistency ratio to determine whether it can be accepted.Based on the multi-objective decision making theory,it combined with the actual state of satellite network nodes and links and the specific requirements of the business,calculating the path that meets the QoS requirements of the service,so as to realize the LEO satellite network multi objective dynamic routing optimization.Established simulation platform based on the iridium network system simulated network delay,the uncertain characteristics like the residual bandwidth and packet error rate,route planning for the randomly generated three classes of business.The simulation results show that,the algorithm not only satisfies the QoS constrain while balancing the traffic load of the satellite link effectively,but also improves the performance on the throughput. 相似文献
13.
基于Globalstar和Odyssey两个Walker delta星座,建立星间链路网络,重点分析网络中的不同轨道间星间链的动态特性,特别是与星上跟瞄系统密切相关的俯仰角、方位角和链路长度变化,为卫星网络路由提供依据.对传统的卫星路由策略作了改进,利用卫星系统的冗余覆盖的特性,选择不同策略下的最优路径.针对用户不能忍受通信中断的情况,提出考虑消除中断的路由策略,进行服务质量的分析比较.同时也比较在消除中断的路由策略下,LEO同MEO网络差异之处.消除通信中断是以其它QoS性能下降为代价. 相似文献
14.
15.
在星地网络的背景下,为了降低由于地面网络链路负载过高导致的传播时延,提出了一种适用于星地网络的负载均衡算法。算法基于网络的链路容量设置一个链路资源利用率作为阈值,当发现路径出现过载的时候分成两步进行路径的预规划:第一步,运用蚁群算法为链路过载的数据流选择其他的路径,以满足地面网内部的负载均衡;第二步,如果仍出现链路超阈值的情况,通过卸载延迟容忍数据流来执行地面与卫星网络之间的负载均衡。仿真结果表明,设定自适应的过载阈值可以有效降低链路的拥塞,与现有算法相比该算法不仅可以更加均匀地分配地面网络中的流量,而且借助卫星网络使地面网络的平均时延降低了18.3%,提高了网络的服务质量。 相似文献
16.
Fabian Mendoza Ramon Ferrus Oriol Sallent 《International Journal of Satellite Communications and Networking》2019,37(6):630-645
Satellite networks are expected to be an integral part of 5G service deployment. One compelling use case is mobile backhauling, where the exploitation of a satellite component can improve the reach, robustness, and economics of 5G rollout. The envisaged availability of new satellite capacity, together with the development of better integration approaches for the provisioning and operation of the satellite component in a more flexible, agile, and cost‐effective manner than done today, are expected to revamp such use case within the 5G ecosystem. In this context, sustained in the architectural designs proposed within H2020 VITAL research project, this paper presents an experimental proof of concept (PoC) of a satellite‐terrestrial integration solution that builds upon software‐defined networking (SDN) technologies for the realization of end‐to‐end traffic engineering (E2E TE) in mobile backhauling networks with a satellite component. A laboratory test bed has been developed and validated, consisting of a small‐scale private mobile network with a backhaul setting that combines Ethernet‐wired links, a satellite link emulator (OpenSAND), OpenFlow switches, and an OpenFlow controller running the network application for E2E TE. Provided results show the operation of a E2E TE application able to enforce different traffic routing and path failure restoration policies as well as the performance impact that it has on the mobile network connectivity services. 相似文献
17.
全球能源互联网的监测、调度、授时、同步及定位等业务均需要能提供广域覆盖、泛在灵活接入服务的可靠通信网络。针对该需求,首先分析阐述全球能源互联背景下各种新型业务需求及其特点,并总结各种业务的共性数据特征;然后论述卫星通信技术的特点以及与全球能源互联网业务特点与数据传输需求的高度契合性,最终提出融合卫星通信网络的全球能源互联网天空地协同网络体系架构。其以IP技术为基础,各层网络通过星间、星地、星空、空空、空地以及地面有线、无线链路连接起来,构建全球覆盖的一体化网络体系。 相似文献
18.
Transport layer implicates a position where satellite networks form one integrated component of hybrid Internet architecture in today's advance technology. However, the Internet has emerged with an important new class of applications that exhibits significant variations of transmission rate over time. Variable‐rate traffic poses a new challenge for transmission control protocol that provides congestion control, especially for applications that need to share the limited capacity of a bottleneck over a long delay Internet path (e.g. paths that include satellite links). Variable‐rate traffic can be produced by persistent transmission control protocol connections and can be impacted by the initial window at the start or during the restart of a session. Current transport research issues are identified related to larger initial window to highlight the expected performance benefits and derive the implications on the design of geostationary satellite Internet systems as the network evolves toward a next‐generation Internet. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
19.
Bergé Patrick Ferreira Afonso Galtier Jérôme Petit Jean-Noël 《Telecommunication Systems》2001,18(1-3):123-135
We analyze the load of the inter-satellite links in polar satellite constellations. Starting from simple considerations on the structure of the underlying network topology, we derive the probability of use of different families of links, with various hypotheses on the nature of the traffic. Our analysis leads to a simple, practical evaluation of the asymptotical link load, which depends on the position of the link. Our model is validated through a constellation simulator, which shows that the results hold even for light load. 相似文献
20.
LEO satellite networks can provide seamless real-time data communication for all kinds of users,which developed rapidly in recent years.At the mean time,the massive payload data down-link system of space data sources,such as remote sensing satellites,still make use of traditional storage and forward mode.The real-time performance of space mission data will be improved effectively,if such satellites are connected to LEO satellite networks equipped with inter satellite links.However,it is necessary to design a specialized satellite network load balancing routing algorithm.Satellite parallel edge-disjoint multipath routing protocol (SPEMR) was designed for remote sensing satellite real-time down-link applications.OPNET simulation results indicate that the performance degradation index(DI) of the multipath scheme implemented by SPEMR is 0.32,which is only 32% of the TLR and 21% of the traditional DSP scheme.It is demonstrated that SPEMR has the better capability of transmitting massive data in real time. 相似文献