网络多流控制器

本文提出了一种实现简单的网络元件,我们称之为多流控制器.多流控制器能够识别汇聚流中的最大速率流并把它从汇聚流中分离出来.多流控制器可以用于汇聚流特征的测量、非拥塞响应流的惩罚等多个领域.本文分析了静态条件下的多流控制器数学模型,本文通过大量ns 仿真,证明了本文给出的数学描述与多流控制器实际工作特征的一致性.     

多线圈汇接网络

汇接网络是通信设备中经常用到的一种电路。它有很多形式,一般用得较多的是由多个混合线圈组成的网络。在德意志民主共和国的“通信技术”杂志上曾译载过匈牙利“MagyarHirddastechnika”杂志所推荐的一种多线圈汇接网络,颇具特色。该文内容比较简单,对许多问题未加深入探讨,这里拟就此作一点进一步的说明。实践表明这种网络具有一些优点。我们在载波设备上曾予以应用,获得了较好的效果。它所用的线圈,在绕制工艺上比混合线圈简单。当汇接或分配的支路数为奇数时,传输衰耗比混合线圈组成的网络要小一些;当传输衰耗相同时,该网络支路之间的隔离效果比一般的汇接网络要好得多。当然,它也存在一些缺陷;当支路数为偶数时,网络所需线圈的总数比     

多波长全光网络

以波分复用 (WDM )技术为基础的多波长 (全 )光网络是当今光通信领域的研究热点。多波长全光网络的现场试验集中反映了与此有关各领域的研究水平和实用化进程。文章着重分析了有代表性的光网试验项目     

智能化多业务网络

首先从不同角度分析了通信服务商目前面临的环境,包括通信服务业的投资趋势、业务发展趋势、服务提供商的业务收入情况以及用户的需求;接着介绍了朗讯的智能化多业务网络的整体架构和解决方案;其中重点描述了智能化多业务网络在网络传输层、业务控制层和应用层上的智能化以及包括核心网络、城域网络在内的六大解决方案。     

多业务网络与多业务运营

电信运营企业的重组意味着我国电信运营企业成为多业务运营企业。随着信息处理技术、计算技术、存储技术、网络技术和传输技术的发展,数据、话音和视频业务之间的界限变得模糊。新的业务形态不断出现,全球各国尝试业务牌照发放方式的改革,基于全IP的多业务核心网络、宽带接入网络被业界看做近期下一代网络发展的方向。本文对多业务运营和多业务网络发展相关的问题进行探讨。     

异构网络中多网络并行传输的网络选择算法

为了充分利用异构网络中的无线资源,提出了一种基于多网络并行传输的异构网络接入选择算法,该算法根据终端接收信号功率确定能够进行通信的无线网络,以这些无线网络的任意非空子集作为候选方案,计算各个方案对应的聚合属性,再根据吞吐量和功耗阈值条件限定候选网络方案,对这些方案建立多属性决策矩阵,采用基于用户偏好的逼近理想值排序法(TOPSIS)得到各个候选网络方案的效用函数值,从中选出与理想方案最接近的多网络接入方案。仿真结果表明该算法能有效改善用户服务质量,提高用户吞吐量,降低用户的单位吞吐量对应的功耗和费用,保证网络的负载均衡。      

基于多网络环境的LTE网络规划设计

在2G/3G/WLAN多网共存的复杂网络环境下建设LTE网络时,需要综合考虑多系统融合组网和规划,这对LTE的精准规划具有非常重要的作用,可以有效提高网络建设效率,降低建设成本,提升网络质量和用户感知。以现有网络数据为基础,针对区域和场景进行融合建模,针对多网络环境下LTE网络规划设计的思路、方法和手段进行了探讨。     

多延迟多瓶颈网络拥塞鲁棒控制研究

研究了具有多延迟用户源端和多瓶颈链路端的复杂网络的主动队列管理控制器的设计和稳定性分析.建立了具有非线性、输入带有时滞和不确定参数扰动的通用网络TCP/AQM动态模型.在平衡点线性化后,采用还原算法进行延迟补偿和预估,将该模型转化为无时滞的线性模型.在系统状态矩阵和输入矩阵参数扰动不满足匹配但有界的条件下,采用积分滑模变结构控制算法,基于Lyapunov稳定性理论和线性矩阵不等式方法给出了滑模可到达和渐进稳定的可行条件,根据该条件设计鲁棒主动队列管理算法.理论证明了该算法的稳定性.     

爱立信ENGINE多业务网络构建基于分组的新型多业务网络

爱立信ENGINE多业务网络解决方案为新老运营商提供了一种可同时支持以前、现在和未来业务的基础设施--最终将构成一个单一、全IP、基于分组的多业务网络,可支持固定和移动通信。提供电信级服务质量(QoS)。爱立信ENGINE多业务网络解决方案使电话和数据通信运营商可以分阶段扩充网络,以此降低运营成本,并最大限度地减少新网络投资的风险。ENGINE横跨从网络核心到网络接入层多个技术解决方案。从2002年1月开始,爱立信已经与全球多家运营商签订了70多份ENGINE合同。     

多源网络编码签名

网络编码可以提高系统的吞吐量,增强系统的健壮性,节省无线网络资源。然而,基于网络编码的系统非常容易遭受污染攻击。已存在的应对污染攻击的方案主要是使用同态签名,并且这些方案几乎都是针对单源网络编码系统的。在本文中,我们提出了一个新的适用于多源网络编码的应对污染攻击的签名方案。该方案使用了环签名和同态哈希函数,每个源节点为它发送的每条消息都生成一个环签名。来自不同源的消息可以在中间结点进行组合。转发者不需要知道源结点的私钥就可以为输出的编码消息生成环签名。验证者无需解码就可以检测出污染消息。该方案是为多源网络编码特别设计的,与文件和分组大小无关。     

QoS enhancement in space data communication: a network coding approach

With the rapid increase of space applications, the amount of information to be transmitted between spacecrafts and ground stations increases exponentially and space–sky–ground Transport Control Protocol (TCP) network is highly demanded. However, the traditional TCP cannot be directly applied to space data communication. This article deeply studies the TCP/Network Coding (NC), which can effectively improve terrestrial wireless communication system throughput. Combined with characteristics of Space Communication Protocol Specification-Transport Protocol (SCPS-TP) and advantages of terrestrial TCP/NC, an improved protocol referred to as SCPS-TP/NC, is proposed for space data communication. This article provides detailed process of protocol design, mathematical modelling and throughput analysis of the proposed SCPS-TP/NC. Finally, we implement the SCPS-TP/NC protocol and evaluate its performance by Network Simulator (Version 2). Simulation results show that SCPS-TP/NC can effectively increase the end-to-end system throughput, reduce the packet loss rate, shorten the transmission delay and improve the Quality of Service (QoS) of space data communication to a certain degree.     

编码TCP的理论研究与应用方法

为了深入理解编码TCP的原理,在讨论TCP Vegas协议和网络编码的基本形式的基础上,分别从无线网络发送端和接收端的角度深入论述了其与网络编码的融合方法以及网络编码层的结构和控制机理,在最后提出了NS2模拟软件底层代码的修改思路来实现检测网络编码TCP性能的目的。     

Rate control-based framework and algorithm for optimal provisioning

Ideally, networks should be designed to accommodate a variety of different traffic types, while at the same time maximizing its efficiency and utility. Network utility maximization (NUM) serves as an effective approach for solving the problem of network resource allocation (NRA) in network analysis and design. In existing literature, the NUM model has been used to achieve optimal network resource allocation such that the network utility is maximized. This is important, since network resources are at premium with the exponential increase in Internet traffic. However, most research work considering network resource allocation does not take into consideration key issues, such as routing and delay. A good routing policy is the key to efficient network utility, and without considering the delay requirements of the different traffic, the network will fail to meet the user’s quality of service (QoS) constraints. In this paper, we propose a new NUM framework that achieves improved network utility while taking into routing and delay requirements of the traffic. Then, we propose a decomposition technique-based algorithm, D-NUM, for solving this model efficiently. We compare our approach with existing approaches via simulations and show that our approach performs well.     

A distributed congestion and power control algorithm to achieve bounded average queuing delay in wireless networks

Allocating limited resources such as bandwidth and power in a multi-hop wireless network can be formulated as a Network Utility Maximization (NUM) problem. In this approach, both transmitting source nodes and relaying link nodes exchange information allowing for the NUM problem to be solved in an iterative distributed manner. Some previous NUM formulations of wireless network problems have considered the parameters of data rate, reliability, and transmitter powers either in the source utility function which measures an application’s performance or as constraints. However, delay is also an important factor in the performance of many applications. In this paper, we consider an additional constraint based on the average queueing delay requirements of the sources. In particular, we examine an augmented NUM formulation in which rate and power control in a wireless network are balanced to achieve bounded average queueing delays for sources. With the additional delay constraints, the augmented NUM problem is non-convex. Therefore, we present a change of variable to transform the problem to a convex problem and we develop a solution which results in a distributed rate and power control algorithm tailored to achieving bounded average queueing delays. Simulation results demonstrate the efficacy of the distributed algorithm.     

基于神经网络的多路无线TCP均衡控制算法

针对无线网络应用,能够有效地使多路的TCP数据业务均衡地使用网络共享资源,需要系统能根据无线网络的容量实时变化,动态调整各路TCP协议拥塞窗口大小,其参数结构复杂,难于建立精确的数学模型。为此提出了一种基于BP神经网络的控制算法,利用它可有效解决多路无线TCP数据业务拥塞窗口的自适应控制问题,为基于无线网络数据业务应用的优化提出一种新的思路。     

Applications of network coding to improve TCP performance over wireless mesh networks: a survey

There is growing interest in the use of wireless mesh network (WMN) as a last‐mile option for Internet access. Despite the many benefits of WMNs, the performance of Internet access may not be ideal. One of the main issues is the interaction of transmission control protocol (TCP) with the underlying network. The poor performance of TCP over multi‐hop networks is well‐documented, and extensive research exists, which addresses TCPs foible and enhance TCP performance for multi‐hop environments. This paper provides a thorough survey of TCP performance issues over WMNs and the available solutions to address these issues. Among the existing methods, we focused on network coding (NC) and the ways that TCP interacts with network coded systems. NC is a technique that encodes the received packets in each node before forwarding them towards the destination. The use of NC in the transport layer to address performance issues raised by wireless access is a recent research topic. This paper presents a detailed study of TCP interaction with NC. Some open research areas in this field are suggested. Copyright © 2012 John Wiley & Sons, Ltd.     

Distributed congestion control strategy using network utility maximization theory in VANET

Cooperative vehicle safety system (CVSS) rely on periodical beacons to track neighboring vehicles.High traffic density often causes channel congestion,seriously damaging the performance of CVSS.Existing congestion control strategies aim to ensure the performance in network layer,without considering the service requirements of vehicles in different driving contexts.To solve the problem,a distributed congestion control strategy using network utility maximization (NUM) theory was proposed.First of all,the NUM model for channel resource allocation was introduced.A utility function reflecting vehicle’s safety requirements was proposed in the model.Then under the condition of fixed transmit powers,a optimization problem of channel resource allocation was proposed.Lastly,to solve the optimization problem,a distributed congestion control algorithm named utility-based rate congestion control (UBRCC) algorithm was designed,the algorithm worked out the optimal beaconing rate by updating vehicle’s congestion price,realizing the resource allocation according to vehicle’s safety requirements.Simulation results validate that UBRCC algorithm can efficiently control channel congestion,reduce transmission delay,ensure reliable data transmission and satisfies the requirements of safety applications.     

网络信息资源标准化探索

从网络信息资源标准化的需求出发,在信息资源的集成化、信息资源的采集和整理、信息资源的存储、信息资源平台的开发、信息服务等方面对网络信息资源标准化进行了论述,旨在为完善网络信息资源的标准化提供参考。     

一种基于主动网络技术的改善无线链路上TCP性能的方案

针对TCP在无线环境中性能下降问题,本文提出一种基于主动网络技术的方案,来改善无线链路上的TCP性能.通过网络仿真,证明这种方案具有更高的性能和更多的优点.     

网络化数控系统的研究和开发

网络化的数控技术是实现制造自动化、智能化、集成化和全球化的基础技术。本文分析了井发网络系统的基本要求,提出了网络化数控系统的体系结构,重点对网络数控系统硬件平台和软件平台的设计与实现进行了阐述分析,并指出了基于Internet的网络数控系统是数控系统的研究发展趋势,有很强的实际应用意义。