GPON系统中ONU快速升级技术研究与设计

主要介绍了吉比特无源光网络系统中光网络单元升级的技术背景及基本原理,分析了光线路终端的带内、带外两种控制模式,并对传统升级方式做了详细分析,发现传统升级方式有很多不足之处,造成了光网络单元升级速度上的瓶颈,提出了一种在带内控制模式下更快的升级光网络单元的设计思路;详细阐述了光网络设备管理和控制接口二层代理的解决方案和升级流程。     

Low cost solution to high capacity 32 × 32 channel FTTH duplex link employing triple play services

In this paper, low cost solution based on RSOAs is proposed for a high capacity 32 × 32 channel, 20 km, FTTH duplex link employing triple play services. Here, downstream transmitters generate a 2.5-Gbps NRZ signal which is routed to both receivers and RSOA-based upstream transmitters. The RSOA modulates this signal with a 1.25-Gbps NRZ signal that effectively overwrites the downstream signal and then it is transmitted back over the same 20 km of bidirectional fiber, where it is routed to receivers at the CO. The proposed model completely eliminates the requirement of separate lasers for upstream communication which makes the system very cost effective. The high-pass filtering effect of the RSOA becomes predominant at higher input powers which has been used as an advantage here to effectively suppress the downstream signal. The impact of RSOA input power and extinction ratio of the downstream signal have been investigated and reported.     

FTTH的新成员--GPON的标准化进展

本简要介绍正在研究的GPON技术,以及GPON作为一种FTTH宽带接入技术的优势、EPON的基本工作原理和实现EPON关键的技术问题。     

上行相干接收的对称10Gb/s长距离WDM-PON

利用基于载波分发技术,对WDM-PON的上行信号采用QPSK调制和相干接收,实现了双向对称长距离传输。仿真实验表明,在不使用任何光放大器的条件下,上行和下行传输速率为10Gb/s时传输距离可达60km,解决了采用无光源ONU时WDM-PON传输距离受限于上行传输的问题。     

一种新的基于认购速率和QoS等级的动态带宽分配算法

为了实现吉比特无源光网络带宽分配的公平性,降低网络的传输延时,设计了一种新的媒质访问控制协议,提出了一种新的动态带宽分配算法.其基本思想是:在保证拥有不同QoS业务的用户得到认购速率的基础上,根据网络负载的大小,动态地将某些用户未使用的带宽分配给其他带宽需求大的用户,以提高网络的带宽利用率.仿真结果表明,这种新的算法在严格控制数据传输延时的前提下,能够保证多用户之间带宽分配的公平性.     

光进铜退用户端设备部署中存在的问题研究

本文对目前光进铜退实施过程中用户端设备部署存在的供电保障、海量设备管理、语音业务开通等问题进行了分析,给出了解决方案。     

影响基于PON的语音业务应用的关键因素及解决方案

本文首先介绍了基于PON的语音业务的几种实现方式,通过比较分析得出软交换方式是性价比最高的方式,然后分析了影响基于PON的语音业务应用的关键因素,对PON的技术特点对不同用户之间语音业务互通的影响进行了重点分析,同时还分析了ONU断电后无法打电话的问题和PON与NGN平台的互通问题等,并针对上述主要问题,提出了切实可行的解决方案.     

Synthesis and properties of novel colorless and thermostable polyimides containing cross-linkable bulky tetrafluorostyrol pendant group and organosoluble triphenylmethane backbone structure

A colorless and high temperature resistant fluorinated polyimide (PI) film based on a novel cross-linkable diamine monomer 4,4′-diamino-4″-(2,3,5,6-tetrafluoro-4-ethylenephenoxy) triphenylmethane (DFPTM) was successfully prepared. The special triphenylmethane backbone and the bulky tetrafluorostyrol pendant group in DFPTM gave the PI material eximious solubility in organic solvents, high tensile properties, good thermal stability, and excellent optical transparency (cutoff wavelength for 331 nm and light transmittance above 94% at 450 nm). Furthermore, the styryl could initiate self-crosslinking reaction to form a dense three-dimensional network structure by thermal curing. Hence, the cross-linked PI film showed superior combination property (including excellent resistance to solvents). It's T_g increased by 57.1–306.0°C, the 5% thermal weight-loss temperature improved by 10.2% to 500.0°C, and the tensile strength enhanced by 17.5% to 39.7 MPa. Moreover, after thermal curing, the cross-linked PI attained a lower elongation at break from 8.1 to 3.9%, and the thermal expansion coefficient reduced from 82.2 to 68.8 ppm/°C without obvious loss of optical transparency (cutoff wavelength for 347 nm and light transmittance remained 93.0% at 450 nm).     

PON在移动城域网中的应用

本文对PON系统的基本原理进行简单介绍,确立了PON的系统定位并着重论述PON在目前城域网中的具体实现及业务承载模式,最后给出相关结论和建议。     

WDM-PON接入技术及其最新进展

本文首先从时分复用无源光网络（TDM—PON）的不足引入波分复用无源光网络（WDM—PON）,接着介绍了ONU波长固定和可调WDM—PON,随后阐述了ONU无色和无光源WDM—PON。鉴于目前WDM-PON难以推广使用的现状,上行用TDMA替代WDMA会使WDM—PON看起来更加现实,所以本文也介绍了混合使用WDM和TDM的HPON。最后对WDM—PON与功率分配PON（PS—PON）的技术进行了比较。