构建宽带业务体系

中国互联网已进入宽带时代,针对宽带业务发展的现状及存在的问题,电信运营商应该根据宽带网络的构建原则,体系的特点以及宽带接入、内容应用、分发承载平台,业务支撑平台等几大关键环节,积极构建宽带业务体系。     

超宽带微波光纤延迟线

介绍了宽带微波光纤延迟线的基本原理、系统组成.叙述了超宽带微波光纤延迟线的研制过程,包括:光发射模块的研制、光接收模块的研制、低噪声前置放大器的研制及整个系统链路的设计、链接、调试等.最后给出了超宽带微波光纤延迟线的测试结果.     

移动宽带业务评价方法研究

从当前移动宽带业务的发展以及用户越来越重视上网体验的趋势,提出传统业务评价方式已经不能适应当前移动宽带业务的发展。阐述了国外移动宽带业务评价活动的开展,传统业务评价方式的缺点和建立基于体验的评价指标体系的必要性。基于视频播放业务的流程,ITU-T的视频业务体验质量模型和国内相关研究成果,探讨了视频业务的评价指标体系。     

APON宽带接入系统的关键技术

以建立基于ATM的无源光网络（ATM－PON）宽带接入系统基本模型为基础，阐述传输帧格式，结合媒体接入控制（MAC）协议对传输帧结构内信元构成机理进行深入分析；对APON系统在物理层传输上的测距技术、突发模式同步技术、突发信号的收发技术进行了探讨，同时提出设计的基本框架。     

基于宽谱光源的光控微波延时技术

提出一种新型的基于宽谱光源和色散器件结合的光控波束形成网络(OCBFN)方案,与利用独立激光器的方案进行了比较,给出了该方案的工作原理和延时链路理论分析,并通过实验验证了该方案实现光控延时的可行性。实验中利用掺铒光纤放大器(EDFA)作为宽谱光源,10 km单模光纤(SMF)作为色散器件实现光路延时,可调谐光滤波器选择光路的工作波长,利用矢量网络分析仪产生微波信号并测量信号延时特性,在9.25~10.25 GHz微波频段中,实验测得的系统延时范围、延时精度及真延时特性(延时大小与微波信号频率无关)验证了基于宽谱光源的可调谐光控微波延时方案的可行性。     

Integrated Circuits for Broad-Band Communications Systems

Integrated circuits for broad-band communication systems which enable broad-band communication between subscribers require LSI's with a performance concerning speed, complexity, and power dissipation which cannot be fully met by present semiconductor technologies. The requirements for coders and decoders, line transmission circuits, and broad-band switching network elements depend upon the system concept chosen. For one chosen system concept, these requirements are derived. By using a representative model for the development of the demand, characteristic curves for the demand of subscriber-line circuits and for central unit elements are resulting. From these curves the optimum semiconductor technologies, complexities, and design strategies are derived. It can be assumed that the results are rather independent of variations of system concept and introduction models.     

高校有线电视宽带综合信息网的建设研究

近年来,全球宽带综合信息网的建设突飞猛进、日新月异。站在科技发展前沿的高等学校应认清形势,抓住机遇,把校园网改造作为学校一项重要的基础设施建设,从而推进高校的现代化步伐。本文介绍了宽带综合信息网的发展趋势,以及有线电视网在宽带接入手段中的优势,并对高校宽带综合信息网的建设与发展提出了几点设想。     

利用超短光脉冲产生宽频带微波脉冲

本文讨论了高效率Ｂｌｕｍｌｅｉｎ型微带光导开关的频率特性及影响其频率特性的参数，指出这种光导开关具有产生大于１００ＧＨｚ微波脉冲的能力。最后给出了实验结果和讨论。     

TD-SCDMA综合视讯业务

针对3G时代的业务模式，业界提出了“综合视讯”的概念。综合视讯的核心则在于其独有的语音和视频交互平台，其使用方式则更加具有普遍性。介绍了TD—SCDMA支持的综合视讯业务种类。以及TD—SCDMA系统支持综合视讯业务的组成部分。详述了大唐移动在TD—SCDMA特色业务发展方面采取的推动措施。     

可运营的综合业务光网络

可运营的综合业务光网络是受业务驱动的一种功能。运营商和企业用户的增多，给光网络带来了可运营的机会。技术的进步和业务需求的变化同时促进了光网络功能的转变。专线业务是最有前景的可运营业务。下一代SDH和城域波分加智能特性是可运营的必须条件。华为光网络已具备了完整的可支营综合业务光网络解决方案。     

电台综合业务网流量监测

综合业务网是个开放型的网络,对外连接着互联网,对内运行着众多的服务,拥有大量的网络设备和终端。要维持网络的正常运作,掌握网内各条链路是否连通,吞吐流量如何,都有些什么应用流量,占用的带宽多少等等是网络运维中必须要突出解决的问题。本文就构建全方位的综合业务网流量监测系统给出了解决方案。     

Improving RCPC Codes in Rate-Adaptive Optical Wireless Communications Systems

In this paper, we analyse the performance of rate-compatible punctured convolutional (RCPC) codes for wireless optical communications systems. For these environments, a novel hybrid RCPC coding scheme with a modified puncturing matrix is proposed based on the insertion of variable silence periods. This transmission technique achieves better bit-error rate results than conventional RCPC and convolutional coding schemes, in agreement to the obtained increase in the peak-to-average optical power ratio.     

极宽频带光纤和极宽频带通信系统

比较了关于光子晶体光纤的水平论述和关于靶向设计的极宽频带三包层单模光纤的观点。基于宏观麦克斯韦方程建立物理模型,提出了靶向设计方法。估算了极宽频带三包层单模光纤批量生产可以接受的公差。研究了服务于宽带中国国家战略的极宽频带光纤和极宽带通信系统。讨论了我国光纤产业的三项目标。     

A Reconfigurable High-Speed Optical System for Integrated Local Communications

The introduction of optical fibers in local area networks makes it possible to implement wide-band communication systems integrating all the communication services (telephone, data, images, etc.) foreseen in future office scenarios. This paper describes a reconfigurable high-speed local communication system, which is currently under development at the Centro Studi e Laboratori Telecomunicazioni (CSELT), conceived to attain high reliability and efficiency features, therefore suitable for a wide range of application environments, such as automated offices, integrated manufacturing, hospitals, etc. The access organization is based on a hybrid (i.e., circuit and packet) protocol, which guarantees each type of traffic the required grade of service, while allowing an optimal exploitation of the transmission capacity. Fault-tolerance issues are taken as a guideline in the overall system conception and, in particular, in the transmission subsystem design. The transmission subsystem presently uses available optical technology to implement a loop-shaped bus topology capable of reconfiguring by means of a distributed algorithms, when a link or node fails.     

宽带实时VBR业务与尽力而为业务复用系统的性能研究

该文以宽带实时VBR业务与尽力而为业务复用系统且对实时业务采取完全共享接纳策略为背景,以系统平均剩余容量、实时业务丢包率和尽力而为业务平均延时为主要研究对象,通过对多业务排队模型深入分析,导出了几个主要性能指标的计算公式,得出了实时VBR业务丢包率随呼叫级负荷增加并非单调增加的新结论。仿真验证了公式的正确性。     

Power Loss Resilience in Laser Diode-Based Optical Chaos Communications Systems

The robustness of laser diode-based optical chaos communications to system power losses has been experimentally studied. In-line optical amplification is shown to be effective in restoring the received optical power to enable successful message extraction at an authorized receiver. At the same time, eavesdropper alert can be achieved by measuring the cross-correlation coefficient.      

高速光纤通信系统中PMD的抑制措施

偏振模色散已成为长距离高速光纤通信系统发展的主要障碍之一.主要从改进光纤本身PMD值、光域补偿、全阶PMD抑制等方面出发,探讨了偏振模色散的抑制措施的基本原理与实现方法.     

7/8自正交卷积码在宽带无线接入系统中的应用

针对TDMA宽带无线接入系统零星误码的问题,设计了7/8自正交卷积码高效结构的编码器和反馈结构的译码器,7/8自正交卷积码的应用使得宽带无线接入系统的误码性能得到较大改善。针对解调器相位模糊和译码器失步的问题,提出了统一的解决方案,应用该方案可获得3dB的功率增益,而且可快速地获得译码器和编码器之间的同步。     

Employment of Voice Band Modems in Subscriber Loop Qualification

This letter presents the method useful in subscriber line qualification for asymmetric digital subscriber line service. It is based on the results of the line frequency response measurement in the voice band by V.34 modems. The response is related to the line attenuation at 300 kHz. The measurement results are also presented.     

高速光纤综合通信网络平台研究

现代通信网络应能满足各种通信业务和通信容量日益发展的需求,实现话音、数据、视频、IP等业务的一体化综合交换和传输。在比较TDM、IP和ATM三种协议的基础上,提出"采用内置RPR和MPLS功能的MSTP平台"建设光纤综合通信网络平台的实现方法。MSTP采用SDH的数据帧结构,保持了SDH标准光接口、灵活分插低速信号、自愈环保护和功能强大的网管等优点,可对TDM、IP和ATM协议进行优化传输。