Hierarchical self-healing rings

Traffic restoration in case of a failure in a circuit-switched telecommunications network involves finding alternate paths for all working paths that are severed by the failure, and rerouting affected traffic on these alternate paths. A new hierarchical self-healing ring (HSHR) architecture for circuit-switched networks is proposed and the design of HSHR networks is considered. A general cost model incorporating both the installation cost and the material cost is used. It is shown that the enumeration method, which finds the optimum configuration of HSHR, can only be used for small networks due to the complexity. Heuristic algorithms to find near-optimum HSHR configurations are presented. The routing and dimensioning of HSHR are also considered. Dimensioning of an HSHR is transformed into dimensioning of single self-healing rings inside the HSHR. Numerical results show that the performance of the heuristic is satisfactory     

Reliability models of a class of self-healing rings

SDH/SONET technology provides the economical and convenient deployment of fault-tolerant high-speed telecommunication networks. This paper analyses a class of SDH/SONET self-healing rings (SHR), i.e. bi-directional SHRs (with two and four fibres) and uni-directional SHRs (including line-switched USHRs and path-switched USHRs). We derived, for both the two-terminal and the all-terminal, reliability models of the above mentioned SHR architectures.     

TCP performance issues over wireless links

This article discusses the problems arising when the TCP/IP protocol suite is used to provide Internet connectivity over existing and emerging wireless links. Due to the strong drive toward wireless Internet access through mobile terminals, these problems must be carefully studied in order to build improved systems. We review wireless link characteristics using wireless LANs and cellular communications systems as examples. We then outline the performance problems of the TCP/IP protocol suite when employed over those links, such as degraded TCP performance due to mistaking wireless errors for congestion. We present various proposals for solving these problems and examine their benefits and limitations. Finally, we consider the future evolution of wireless systems and the challenges that emerging systems will impose on the Internet protocol suite     

Deployment issues for the IP multicast service and architecture

IP multicast offers the scalable point-to-multipoint delivery necessary for using group communication applications on the Internet. However, the IP multicast service has seen slow commercial deployment by ISPs and carriers. The original service model was designed without a clear understanding of commercial requirements or a robust implementation strategy. The very limited number of applications and the complexity of the architectural design-which we believe is a consequence of the open service model-have deterred widespread deployment as well. We examine the issues that have limited the commercial deployment of IP multicast from the viewpoint of carriers. We analyze where the model fails and what it does not offer, and we discuss requirements for successful deployment of multicast services     

面向服务的舰载作战指挥控制系统集成研究

提出一种以业务为核心面向服务的舰载作战指挥控制系统软件集成架构方法。该软件架构采用SOA思想,利用业务流程来组织系统应用,实现以数据为中心向、以业务流程为中心的转向,使系统能够快速响应不断变化的应用需求;系统功能和数据作为可被发现和重用的资源均可在网络上发布,实现以平台为中心向以网络为中心的转向,从而提升舰载作战指挥控制系统在网络化、信息化条件下的互操作和信息共享能力。     

基于CCS的FFT的设计与实现

给出了按时间抽取的基-2FFT设计流程图,并对使用CCS工具的FFT变换结果和使用C语言程序计算的FFT变换结果进行比较。结果表明,使用TI公司的函数库DSPLIB不仅编程方便,程序的可读性强,而且实现同样的功能时操作简单,应用开发时间相对较小。     

基于MATLAB与CCS的联合算法仿真

基于CCS(Code Composer Studio)开发DSP上可执行的目标图像处理算法仿真中,原始图像数据不容易获取与调用,处理结果不能可视化.针对这一问题,提出了一种基于MATLAB与CCS联合仿真的解决途径,并结合目标形心跟踪算法,论述了联合仿真方法的具体实现.通过这种方法,切实解决了CCS原始数据快速获取、处理结果的可视化等问题.该方法不仅适用于TI 6000系列DSP,同样适用于5000系列及2000系列的DSP;不仅应用于图像处理系统,也适用于雷达信号、语音信号等的频谱分析.     

基于CCS的数字图像直方图均衡化的设计

直方图均衡化是最常用的图像增强方法之一,目前大多是用Matlab软件仿真,不利于硬件实现。为了克服这一不足,这里给出了直方图均衡化算法以及程序设计流程,并在CCS v3.1的软件仿真环境下进行仿真实验。结果表明,对图像进行直方图均衡化达到了增强的效果。这为图像处理提供了一种硬件实现的方法。     

WiMAX系统部署研究

作为一种宽带无线解决方案,WiMAX系统的覆盖范囤大,且无须耗资建设昂贵的有线设施.与有线网络相比,它具有成本高效和部署迅速等优势.给出了WiMAX系统的部署模型,介绍了WiMAX系统的组网结构,列举了WiMAX系统的部署场景,分析了WiMAX系统的网络配置.     

基于CCS的图像边缘检测和提取设计

Matlab对数字图像的处理在工程化方面存在一定的不足。针对这一不足,利用硬件仿真平台CCS,采用数字图像灰度梯度最大值法、Sobel算子边缘检测算法对数字图像进行检测,实现了数字图像的边缘提取。实验表明,Sobel算子边缘检测算法对数字图像进行边缘检测和提取的效果比较理想,且为图像处理提供了一种硬件实现方法。     

基于CCS的数字图像边缘检测的设计

数字图像边缘检测的设计大多是基于Matlab软件设计的,这与工程化还有一定的距离。针对这一不足,给出了数字图像边缘检测Sobel算子以及程序设计流程,并在CCS v3.1的软件仿真环境下进行仿真实验。通过3个实例的分析,验证了基于CCS的数字图像边缘检测设计的可行性。结果表明,使用Sobel算子实现了图像边缘检测,这为图像处理提供了一种硬件实现的方法。     

A self-healing ATM network based on multilink principles

Self-healing is the ability of a network to reconfigure itself around failures such that calls in progress are not dropped and suffer of no or almost no degradation in quality of service. Providing self-healing capabilities in all parts of the future ATM network in a cost effective way is therefore a key challenge. A new self-healing method based on the multilink concept is presented for dedicated parts of the ATM network, such as, for instance, feeder networks. In the multilink concept that is proposed, the cells of an ATM connection carried by a multilink are distributed over several physical links. If a physical link supporting the multilink fails, the cells will be distributed among the remaining physical links thus providing a self-healing capacity. In this way the quality of service can be maintained at the expense of a higher load on the remaining physical links. The speed of restoration only relies on the detection and signaling of the failure since spare capacity is available on the very multilink. The sharing of spare capacity in addition to the statistical multiplexing gain provides a cost effective self-healing method and leads to a simplified network resource management. The proposed multilink concept is based on an extension of the multipath self-routing concept, which is currently applied by Alcatel in its ATM switching fabric     

NFV故障关联及故障自愈方案研究

利用NFV实现电信网络设备软硬件解耦,摆脱了对专用硬件设备的依赖,并能利用NFV资源共享、自动部署、弹性伸缩等特性,但同时也带来了故障点多、故障定位分析困难等问题,导致NFV网络的运营维护难度增加。分析了NFV故障处理的流程及故障关联方案,为NFV场景下的故障定位处理提供指引。同时给出了VNF故障自愈实现方案,利用VNF特性,实现网元及业务自愈,提升自动化运维能力。     

基于FDATool和CCS实现滤波器设计的教学

本文探讨了一种采用FDATool设计滤波器,调用TI公司标准数字信号处理算法库函数DSPLIB完成滤波器的DSP实现的教学方法。该方法既有助于学生掌握滤波器的设计技术,又能克服采用传统汇编程序或标准C／C＋＋程序直接编程实现滤波器的不足,还适用于DSP系统工程设计。使用该设计方法能显著提高编程效率,有效缩短DSP开发周期。     

基于CCS的DSP片外Flash直接烧写设计

要可靠启动DSP系统中用户代码,关键是Flash正确可靠烧写.提出了一种基于CCS简单、容易理解的直接烧写方法.通过恰当设置COFF代码段,保存运行地址必需的DATA,以在线编程的方式将保存的DATA烧写到外部Flash中.采用TMS320C6711 DSP试验板,对Flash烧写上电加载后,DSP能够正确、稳定的运行.给出了直接烧写方法,操作简便,容易掌握,为DSP系统中Flash的烧写提供了一条有效解决途径.     

基于CCS的DSP片外Flash直接烧写设计

要可靠启动DSP系统中用户代码,关键是Flash正确可靠烧写。提出了一种基于CCS简单、容易理解的直接烧写方法。通过恰当设置COFF代码段,保存运行地址必需的DATA,以在线编程的方式将保存的DATA烧写到外部Flash中。采用TMS320C6711 DSP试验板,对Flash烧写上电加载后,DSP能够正确、稳定的运行。给出了直接烧写方法,操作简便,容易掌握,为DSP系统中Flash的烧写提供了一条有效解决途径。     

Enabling Applications Deployment on Mobile Networks

There is much interest in the possibility of both wireless and wireline network operators earning new revenues by encouraging the independent application development community to create new, useful ways of exploiting network capabilities; historically such capabilities have been under the exclusive control of the network operator. There are various initiatives supporting this aim through the specifications and promotion of standard application programming interfaces (APIs) that can be used to access these network functions. This paper gives an overview of the main initiatives and examines factors such as developer engagement and policing, that will affect the successful deployment and use of network APIs but that are unrelated to their exact technical specification. This revised version was published online in July 2006 with corrections to the Cover Date.     

CSFB部署对网络的影响分析

因为LTE的主要驱动力是数据业务,其本身不能提供语音业务,所以对WCDMA运营商来说,在VoLTE产业成熟之前要发展语音业务就需要部署CSFB.介绍了CSFB的实现原理,并从部署CSFB的角度对CSFB的不同实现方式对网络的改造要求、路由区和位置区的划分、实际部署的组网方案等方面进行了详细分析,最后针对不同的网络情况给出了部署建议.     

港口生产调度组织过程优化探析

文章分析了目前港口生产调度组织过程中存在的问题, 提出了港口生产调度组织过程采用并行工程进行优化的方法, 为提高港口生产调度质量提供了参考。