pnpn结构器件模型的分析与模拟

将基本半导体方程归一化为奇异振动问题，采用渐近和数值技术，研究了ｐｎｐｎ结构器件模型解的分歧现象，确定了模型解唯一以及模型解出现Ｓ分歧的歧点，由此获得了Ｊ－Ｕ渐近解析表达式。实际例子表明，所获Ｊ－Ｕ的解析式与数值解结果一致。     

ATM论坛UNI4.0与ITU—T Q.2971

就ＡＴＭ论坛ＵＮＩ４．０与ＩＴＵ－Ｔ Ｑ．２９７１二者在点到多点信令的实现方面作了对比，分析其相同点及不同点，并着重讨论了ＵＮＩ４．０的ＬＩＪ信令方式，提出了具体的实现策略。     

会议电视系统常见故障的排除

会议电视系统常见故障的排除沈才良会议电视系统一般由编解码器（ＣＯＤＥＣ）、房间系统（摄像机、监视器、Ｕｃ－５０、ＲＭ－５０会议控制器、回声抑制器）、多点控制单元（ＭＣＵ），以及２Ｍｂ／ｓ或ＤＤＮ网络Ｖ３．５专线组成。下面将会议电视（ＣＬＩ公司产品）中...     

基于PNNI和UNI4.0信令规范的多点间呼叫控制的研究

提出了一种基于ＡＴＭ论坛ＰＮＮＩ１．０和ＵＮＩ４．０信令规范的叠加型多点通信子网的实现方案－－叠加子网多点间呼叫控制ＯＭＣＣ方案,使得到支持和不支持多点间呼叫的交换机组成的混合网络中可以实现组内广播类型的多点间呼叫。指出了多点间呼叫的实现对提供多媒体业务和数据通信的重要作用。     

“国际电信联盟”简介

随着计算机网络技术、数据通信技术的发展，以及相应市场的成熟，读者在阅读有关文献时逐渐开始接触到“标准”的概念，最初往往是从ＣＣＩＴＴ标准开始，之后又会看到ＩＴＵ－Ｔ标准。本刊最近约请王玉荣同志撰文，详细介绍有关情况，包括ＩＴＵ的由来、组织机构以及ＩＴＵ－Ｔ标准化工作过程。     

用UNIX系统的UUCP进行远程维护

根据ＵＮＩＸ操作系统的特点，提出了用ＵＮＩＸ系统所包含的网络软件包ＵＵＣＰ进行应用软件的远程维护，并详细地介绍了ＵＵＣＰ的工作原理、使用Ｕ－ＵＣＰ时软、硬件的设置方法以及远程维护的具体实现。     

会议电视第五讲会议电视的多点控制单元(MCU)

本文首先说明了ＭＣＵ的功能，多点控制的主要模式，然后分析了国际上应用较多的一种ＭＣＵ，最后介绍一种国内开发的ＭＣＵ。     

多点多媒体会议的系统结构模型

多点多媒体会议是多媒体通信的一个十分重要的应用。近年来，国际电信联盟针对这方面的应用制定了ＩＴＵ Ｔ１２０和ＩＴＵＴ１３０系列建立和草案，提出了多点多媒体通信系统的模型和结构。论文通过对这两个系列协议的研究，介绍了其主体模型框架，并对其实现方法做了一些探讨。     

ATU UNI信令的功能划分

ＡＴＭ用户－网络接口（ＵＮＩ）信令采用ＯＳＩ的分层结构，本文首先简要介绍了ＡＴＭ ＵＮＩ信令协议的体系结构以及各层的功能。然后详细描述了ＵＮＩ信令功能模块的划分，以及各模块的功能。     

SDH不可用秒的统计和收集

严格按照ＩＴＵ－Ｔ有关建议的定义，对ＳＤＨ管理网中性能管理参数不可用秒的精确设计设计了流程，更着重解决了性能收集时间段分隔点处ＵＡＳ的统计和收集的解决方法。     

提高七号信令运行安全性的几点意见

本简要讨论了为提高七号信令运行安全性可采取的几个措施，其中主要介绍了信令点再启动功能。     

Feedback methods for calls allocation on the crossed traffic routing

The paper presents new methods to allocate telephone calls whenever they can use two or more routes. The most sophisticated of them require the use of the common channel signalling as a feedback link for the observations. The relative performances of the different methods as obtained by simulation are presented.     

The development of broadband signalling platforms

Mao Zedong once said: "All genuine knowledge originates in direct experience." This paper describes the experiences gained through a range of development projects, all concerned with the design, development, demonstration and maintenance of real broadband signalling systems. The authors have participated in the development of a variety of systems offering broadband capabilities, all of which support some form of broadband signalling between the service user and the service provider. The process of designing and building such systems can provide invaluable insights into issues such as development methods, signalling performance, programming interface definitions, etc, none of which are apparent from purely paper-based studies or through the standards specification process.This 'coal-face' experience covers both collaborative as well as internal BT projects, with each system being subject to a wide variety of service requirements. In addition, the period of work covered by the developments described in the paper encompasses broadband signalling systems that on the one hand predate the published ITU-T standards on broadband ISDN systems and on the other include a comprehensive testbed supporting an interworking set of broadband signalling interfaces based on the appropriate signalling standards defined by both the ATM Forum as well as the ITU-T.     

集群系统与综合业务数字网互连方式

提出了集中控制方式的集群系统与ＩＳＤＮ互连的两种接口方案，讨论了使用ＭＰＴ１３２７信令与ＩＳＤＮ用户／网络间协议，以及与Ｎｏ．７信令的ＩＳＤＮ用户部分（ＩＳＵＰ）的交换及实现方法。     

Methods for the connection of signalling units to switching networks

Two methods for the connection of signalling units to digital switching networks are presented. The proposed methods make it possible to connect singalling units without affecting the traffic characteristics of networks.     

Europäische Normen für die Signaltechnik

This article introduces the basic standards for signalling according to CENELEC and discusses the main methods and procedures for future demonstration of safety.     

A REASSEMBLY STRATEGY FOR REDUCING IN/PCS SIGNALLING TRAFFIC

This paper proposes a simple assembly/disassembly part (ADP) for the signalling system no. 7 (SS7) protocol to reduce the signalling traffic loads in intelligent networks (IN) and personal communication service (PCS) networks. The ADP combines two or more messages with the same destinations into a single message, thereby reducing signalling traffic without affecting SS7 protocol operations. The numerical results show that the proposed method can reduce traffic among signalling points 9∼17%.     

Signalling end-to-end optical services over multi-domain networks

This paper proposes a new UCLP (User-Controlled LightPath) architecture that offers end-to-end optical services provisioning in a multi-domain network. It also shows the experimental results of our UCLP software tool implemented on the Canarie optical network testbed. This work is motivated by the growing need for end-to-end lightpaths to support high volume data transferring applications such as GridFTP (GRID File Transfer Protocol) and SAN (Storage Area Networks) over multi-domain networks. The main problems encountred while provisioning end-to-end optical service in a multi-domain network are investigated and a review of the different interdomain signalling approaches is provided in comparison with our user-controlled lightpath provisioning approach. Various interdomain signalling approaches are discussed and compared to justify the necessity of signalling methods at the application level for long-duration applications.     

Comparative study of signalling methods for high-speed backplane transceiver

A combined analysis of transient simulation and statistical method is proposed for comparative study of signalling methods applied to high-speed backplane transceivers. This method enables fast and accurate signal-to-noise ratio and symbol error rate estimation of a serial link based on a four-dimension design space, including channel characteristics, noise scenarios, equalisation schemes, and signalling methods. The proposed combined analysis method chooses an efficient sampling size for performance evaluation. A comparative study of non-return-to-zero (NRZ), PAM-4, and four-phase shifted sinusoid symbol (PSS-4) using parameterised behaviour-level simulation shows PAM-4 and PSS-4 has substantial advantages over conventional NRZ in most of the cases. A comparison between PAM-4 and PSS-4 shows PAM-4 gets significant bit error rate degradation when noise level is enhanced.     

Resource allocations in relay‐assisted cellular networks

In a relay‐assisted cellular network, the transmission mode (either direct transmission or relaying) and the transmit power of the source and relay nodes affect not only transmission rates of individual links but also the rates of other links sharing the same channel. In this paper, we propose a cross‐layer design that jointly considers the transmission mode/relay node selection (MRS) with power allocation (PA) to optimize the system rate. We first formulate an optimization problem for a cellular system, where the same frequency channel can be reused in different cells. A low complexity heuristic MRS scheme is proposed on the basis of the link and interference conditions of the source and potential relay nodes. Given the transmission mode and relay node (if the relaying mode is chosen) of each link, the transmit power of the source and relay nodes can be solved by geometric programming. This method for MRS and PA can achieve a close‐to‐optimum performance, but implementing the PA requires heavy signalling exchanged among cells. To reduce the signalling overheads, we finally proposed a heuristic and distributed method for MRS and PA inspired by some asymptotic analysis. Numerical results are conducted to demonstrate the rate performance of the proposed methods.Copyright © 2013 John Wiley & Sons, Ltd.