新一代光接入网EPON

EPON是一种新出现的光接入网技术，它是基于以太网的无源光网络，被认为是下一代接入网的最佳选择。它以光纤作为传输介质，主要传送以太网的数据帧，它采用无源分光器实现点到多点的连接。由于EPON全部采用无源器件因此其维护简单，成本降低。在本文中重点介绍了接入网的发展，EPON的体系结构、工作原理和EPON的关键技术。     

EPON ONU芯片的硬件验证与测试平台设计

介绍了SHU 2006 ONU芯片的硬件验证与测试平台系统,利用该验证平台实现了SHU 2006 ONU芯片的功能以及TBI高速接口的时序测试.在该验证平台上,100M以太网的FTP数据传输速率可以达到8Mb/s.     

EPON在光进铜退改造工程中的应用

以FTTB LAN模式下的多业务接入和FTTN DSL模式下接入点的选择为基础,着重介绍了EPON在陕西电信光进铜退改造工程中的应用,最后通过实例介绍了FTTx网络部署中局端设备和网管的规划。     

10G EPON的ONU硬件设计与实现

基于802.3av D2.1草案对10G EPON的ONU进行了硬件设计,提出了以Virtex5 FPGA为核心的解决方案.该设计能实现802.3av D2.1草案所规定的ONU基本功能,并且为ONU专用ASIC芯片的设计奠定了基础.     

以太无源光网络中突发发射模块的设计

突发发射模块是以太无源光网络系统中非常关键的一个器件,本文详细讨论了突发发射模块的要求、原理和设计技术,并给出了我们的实验结果.     

基于EPON的全业务接入

随着IP业务的迅速发展和各种新业务的不断涌现，对网络的接入带宽和接入能力提出了很高的要求。在各种宽带接入网技术中，以太无源光网络具有高带宽、高效率和易扩展等特性，能够接入现有和未来的多种业务，有效解决了在用户接入侧的带宽“瓶颈”问题，成为宽带光接入的最佳选择。介绍了EPON的层次结构和工作原理。并分析了EPON实现全业务接入的技术。     

EPON光接收灵敏度研究

结合IEEE 802.3 ah标准中的以太无源光网络(EPON)接收灵敏度指标,着重分析了接收灵敏度光调制幅度(OMA),该OMA指标的采用有利于系统降低对消光比的要求,使发射机和接收机的设计更加简单;最后,简要讨论了OMA和增强型接收灵敏度的测试,指出增强型测试更有实际意义。     

EPON:下一代接入网的最佳选择

EPON技术具有大带宽、高性价比、结构简单和一定服务质量保证等特点，被业界普遍看好，成为下一代接入网的最佳候选技术。本文主要介绍了EPON的工作原理、分层结构、接入控制和组帧方式，最后给出了实现EPON的关键技术和难点以及EPON的发展近况。     

EPON光收发模块的性能要求

文章针对EPON系统的各个技术特点，分别阐述了其对系统所用光收发模块的性能参数的要求，同时旬出了IEEE802.3ah对这些参数的建议，并对目前业内EPON光收发模块的研发现状和今后的发展方向做了一定的分析。     

EPON在用户接入网的应用研究

本文简单介绍了中国电信集团采用EPON试验的情况,然后分析了目前新兴运营商在写字楼内的组网方案及存在的问题,有针对性地制定了EPON应用于写字楼的系统测试方案,测试结果表明EPON能够较好地满足写字楼客户需求.在此测试基础上,文章对EPON在写字楼和小区的应用模型和经济性进行了分析,并提出EPON近期的应用策略.     

EPON中光收发终端注册的模块设计研究

在对EPON系统的组成、结构、工作原理、多点控制协议进行了介绍的基础上,阐述了ONU注册的过程以及注册过程中会出现的冲突问题及其解决办法,并分析注册过程特点,通过相应功能模块实现ONU注册。仿真结果进行分析表明,ONU能够快速准确的在OLT上实现注册。     

EPON光功率计系统设计与实现

通过分析EPON技术及其系统传输信号特点,对上行和下行信号采取不同的硬件电路结构,重点设计了专用硬件电路用于突发尖脉冲信号的捕捉,从硬件上解决了上行突发光信号功率值准确测量的问题,研制出了EPON在线测量的光功率计。     

QoS and service interworking using constraint route labeldistribution protocol (CR-LDP)

Introducing quality of service features to the IP/TCP protocol suite has become a hot topic of research in both industry and academia. Several architectures have been proposed for QoS support at the network layer (layer 3 in the OSI model). Both integrated services and differentiated services architectures are examples of QoS models that are implementable at the IP layer. Another development at the IETF is the work related to traffic engineering using multiprotocol label switching. While traffic engineering covers a wide range of topics, QoS support is recognized as one of its necessary features. This article describes the QoS features of the constraint-route label distribution protocol and how they can be efficiently utilized to achieve service interworking between a number of different networking technologies     

具有APD-TIA光模块的饱和光功率偏低研究

GPON ONU用光接收模块的光接收灵敏度和饱和光功率分别要求-28dBm和-8dBm。测试表明,具有2.5Gb/s APD-TIA光接收模块在25℃和85℃下接收光灵敏度和饱和光功率一般没问题,但在-40℃下,部分模块饱和光功率低于-8dBm。分析指出,饱和光功率偏低,主要与APD的结构、温度特性以及TIA、AGC性能有关。     

Optical power budget enhancement in next-generation DDO-OFDM-based optical access networks using square root module

A passive optical network based on orthogonal frequency division multiplexing (OFDM-PON) gives improved performance for high speed optical access network due to its greater resistance to fiber dispersion and higher bandwidth efficiency. In optical fiber communication, chromatic dispersion (CD) is a linear distortion in fiber, but it is converted into nonlinear distortion due to square-law characteristic of photo diode detector at the receiver side resulting in degradation of performance. To compensate for this nonlinear distortion, we proposed to use a linearized receiver circuit with square root module (SRM) device which can improve the performance of system in terms of CD tolerance. In this paper, we have analytically analyzed the performance of OFDM-PON system with and without SRM device for direct-detection optical OFDM-PON (DDO-OFDM-PON) system. At BER of \(10^{-3}\), which is the limit of forward error correction, there is 11.1 and 13.5 dB improvement in optical budget with SRM for downstream and upstream direction, respectively, as compared to conventional DDO-OFDM-PON system.     

+20 dBm output power balanced optical amplifier module

A novel and efficient balanced optical amplifier (BOA) configuration is proposed. In this technique the four ports of an erbium fibre multiplexer are used to combine signal and pump in a symmetric fashion, providing dual pumping while preventing pump crosstalk. The use of the BOA design in a 980 nm pumped erbium doped fibre power booster packaged module is demonstrated. Furthermore, tests of a +20 dBm output BOA as a power amplifier in a 5 Gbit/s transmission experiment result in successful bit error rate measurements through 86 km of nondispersion shifted fibre.<>     

EPON中一种新型的ONU休眠节能机制研究

为实现以太网无源光网络(EPON)的能源节省,提出了一种新型的基于双向业务流量的光网络单元休眠节能的控制机制。该机制通过扩展多点控制协议,并根据业务汇聚到缓存的容量来进行ONU休眠节能的时隙安排。仿真结果表明,该机制在实现绿色节能的同时可有效保证EPON网络的性能。     

基于能量采集模块的智能型无功补偿控制器

通过对目前市场上低压无功补偿控制器比较和分析,提出了一种基于电表专用能量采集模块的智能型无功补偿控制器.该控制器简化了系统结构,缩短了系统软硬件设计开发周期,具有采样转换速度快、精度高和抗干扰能力强等优点.介绍了该控制器的能量采集模块、系统硬件结构、软件设计流程及其系统特点.     

Efficient use of protocol stacks for LAN/MAN-ATM interworking

Connectionless (CL) services as already developed in LANs, have to interwork with emerging asynchronous transfer mode (ATM) connection-oriented (CO) networks. MANs are a significant evolutionary step and CO MANs, in particular, constitute a technically appealing method to integrate both environments and provide shared medium access for all services. The functions required for enhancing distributed-queue dual-bus (DQDB) MANs with CO services in a way compatible with ATM are described. Within the integrating framework of B-ISDN, the practically useful scenarios for interworking LANs, CO and CL MANs, and ATM are investigated and classified in order to exploit the advantages of an efficient protocol relay utilizing the resources of the lowest possible layer. This is aimed at assisting interworking unit (IWU) designers and implementors to decide on key options in this versatile and evolving environment. The CO DQDB case emerges as the most advantageous development in terms of interworking simplicity and robustness     

软交换IP信令互通研究与实现

目前,如何实现下一代网络(NGN)软交换技术中4种关键的协议,即H.323、会话初始协议(SIP)、媒体网关控制协议(MGCP)和H.248的互通有着十分重要的意义.文章在对这些协议进行简要阐述的基础上,提出了软交换信令互通的解决方案,并根据呼叫状态的变迁给出了部分主要的信令映射关系,最后,通过具体实例说明了互通的实现方法.