三种宽带无源光接入网技术比较

无源光网络(PON)是一种新兴的覆盖最后一公里的宽带光纤接入技术.随着PON的发展,应用于PON的技术也层出不穷,基于ATM的无源光网络(APON)/宽带无源光网络(BPON)、以太网无源光网络(EPON)以及最近出现的千兆以太网无源光网络(GPON)技术都进一步推动了宽带光接入网的发展.文章回顾了宽带PON技术的发展,介绍了3种宽带PON技术,并对它们进行了比较和分析.     

FTTH两大实现方式：EPON和GPON

无源光网络(PON)是实现FTTH的主流方式,其中,基于ATM的宽带无源光网络(BPON)由于种种因素不宜采用。本文分析比较了以太网无源光网络(EPON)和吉比特无源光网络(GPON)的关键技术,并介绍了这两种宽带PON技术的设备互通性和产品进展情况。     

PON业务常见故障的处理

无源光网络(PON,Passive Optical Network)采用无源光分/合路器或光耦合器分配/汇聚各光网络单元(ONU,Optical Network Unit)信号的光接入网。PON系统系由光线路终端(OLT,Optical Line Terminal)、光分配网(ODN,Optical Distribution Network)、光网络单元(ONU)组成的信号传输系统,简称PON系统。目前主流PON综合接入系统根据采用的技术分为以太网无源光网络(EPON,Ethernet Passive Optical Network)和吉比特无源光网络(GPON,Gigabit-capable Passive Optical Networks)。     

一种融合EPON和GPON的接入方案

无源光网络(PON)突破了传统的点到点解决方法的局限,一直被认为是光接入网中最具发展前景的技术.由于光接入网应用环境复杂多样,PON应用技术也呈现出多样化的特点.以太网无源光网络(EPON)和千兆无源光网络(GPON)是其中两种具有代表性的接入技术.文章根据光纤到户实际工程的需要,论述了一种融合EPON和GPON技术的接入方案.     

PON发展现状及思考

无源光网络(PON)是近几年兴起的新技术,包括ATM无源光网络(APON)、以太无源光网络(EPON)和千兆无源光网络(GPON).指出了它们的关键技术和系统特点,并进行了详细比较.同时,介绍了PON技术的发展现状,并对PON的未来发展提出了建议.     

一种新型模式耦合器的设计及应用

基于多模干涉耦合器光波导结构提出一种新型模式耦合器。该模式耦合器在对下行光信号分束的同时,实现对上行光信号的低损合束。文中研究该模式耦合器针对GPON(吉比特无源光网络)、XGPON(10千兆比特无源光网络)、EPON(以太网无源光网络)和10G-EPON等无源光网络应用的光损耗特性。研究结果显示,该模式耦合器能有效降低无源光网络的上行光链路损耗,提高系统光功率预算。在此基础上,文中还提出基于该模式耦合器的PON OLT(光线路终端)光模块实施方案以及基于该模式耦合器的长距大分光比PON的网络架构。     

探究波分复用无源光网络核心技术

现在无源光网络(PON)是解决接入网最后的关键技术,也是实现FTTX最具有新引力的技术手段。"无源"就是说ODN中没有任何一个有源的电子器件和电子电源,完全都是由光分路器(Splitter)等无源器件所构成的。所以,他的管理维护的投入资金比较少,这是PON在接入网发展过程中比较具有优势的一个方面。按照信号分配方式对PON进行分来可以分成功率分割型无源光网络(PSPON)以及波分复用型无源光网络     

下一代光通信网的演进

介绍了光通信网及其相关的光传输网和光接入网技术的发展,指出了下一代光通信网的演进方向:光传送网(OTN)、自动交换光网络(ASON)、全光网络、无源光网络(PON)和家庭网络.     

EPON技术在青海电网的应用

无源光网络(PON)技术越来越受到人们的关注,PON是一种单纤双向的点到多点(P2MP)结构的无源光网络,EPON具备了以太网和PON的优点,由光线路终端OLT(Optical Line Terminal)、光网络单元ONU(Optical Network Unit)和无源分光器POS(Passive Optical Splitter)组成。介绍了EPON技术的主要优缺点,并与其他通信技术进行了比较,概述了EPON的系统结构,以及EPON技术在青海电力网中的应用,展示了EPON技术广泛应用的美好前景。     

下一代无源光网络xPON系统浅析

无源光网络(PON)是未来光纤接入网的一个主要发展方向,目前主流的PON标准有EPON和GPON两种,本文通过对这两种主流PON标准技术的分析和比较,提出了下一代无源光网络的系统模型,并对此模型的特点作了进一步的分析。     

Sleep assistive dynamic bandwidth assignment scheme for passive optical network (PON)

In passive optical network (PON), in addition to efficient bandwidth management, a dynamic bandwidth assignment (DBA) scheme can also enhance the energy efficiency performance of the optical networks units (ONUs) during sleep mode. A few such green DBA schemes have been proposed in literature for EPON, however, ITU compliant PONs have not got attention. In this study, the role of a DBA scheme during the cyclic sleep mode for XGPON has been investigated. A sleep assistive (SA)-DBA scheme is proposed that not only improves the energy saving performance of cyclic sleep mode but also reduces the upstream delays and variance for all the type-2 (T2), type-3 (T3) and type-4 (T4) traffic classes. Although, the upstream delay of type-1 (T1) traffic class slightly increases, the average upstream delay of all the traffic classes remains below the set target delay limit of 56 ms.     

Analysis of mean packet delay for upstream transmissions in passive optical networks with sleep mode

The sleep mode has been introduced to improve the energy efficiency of passive optical networks (PONs) with interleaved polling with adaptive cycle time (IPACT) as a medium access control (MAC) scheme. For energy saving, the sleep mode of each optical network unit (ONU) is activated based on the packet queue length for upstream traffic. We model such a PON as an N-user M/G/1 queue with reservations and vacations. Based on the framework of M/G/1 queueing analysis with some modification made to incorporate the nature of IPACT as well as the sleep mode, we derive a closed form expression of the mean packet delay. A unique challenge in our analysis is that certain quantities such as the residual time of an on-going sleep period for the upstream channel must be considered from the network's viewpoint while the delay due to the sleep mode experienced by a packet must be considered from the ONU's viewpoint. Simulation experiments are conducted to validate the analytical results and to show that the results are relatively insensitive to packet arrival statistics for large sleep periods. Finally, we demonstrate how a sleep period can be chosen given the quality-of-service (QoS) requirement on the mean packet delay.     

Efficient Power‐Saving 10‐Gb/s ONU Using Uplink Usage‐Dependent Sleep Mode Control Algorithm in WDM‐PON

We propose and demonstrate an efficient power‐saving optical network unit (ONU) based on upstream traffic monitoring for 10‐Gb/s wavelength division multiplexed passive optical networks (WDM‐PONs). The power‐saving mode controller uses a μ‐processor and traffic monitoring modules followed by the proposed power‐saving processes to operate the sleep mode ONU. The power consumption of the ONU is effectively reduced from 19.3 W to 6.4 W when no traffic from the users is detected. In addition, we design a power‐saving mechanism based on a cyclic sleep mode operation to allow a connectivity check between the optical line terminal and ONU. Our calculation results show that the WDM‐PON ONU reduces the power consumption by around 60% using the proposed mechanism.     

Energy-saving scheme based on downstream packet scheduling in ethernet passive optical networks

With increasing network sizes, the energy consumption of Passive Optical Networks (PONs) has grown significantly. Therefore, it is important to design effective energy-saving schemes in PONs. Generally, energy-saving schemes have focused on sleeping the low-loaded Optical Network Units (ONUs), which tends to bring large packet delays. Further, the traditional ONU sleep modes are not capable of sleeping the transmitter and receiver independently, though they are not required to transmit or receive packets. Clearly, this approach contributes to wasted energy. Thus, in this paper, we propose an Energy-Saving scheme that is based on downstream Packet Scheduling (ESPS) in Ethernet PON (EPON). First, we design both an algorithm and a rule for downstream packet scheduling at the inter- and intra-ONU levels, respectively, to reduce the downstream packet delay. After that, we propose a hybrid sleep mode that contains not only ONU deep sleep mode but also independent sleep modes for the transmitter and the receiver. This ensures that the energy consumed by the ONUs is minimal. To realize the hybrid sleep mode, a modified GATE control message is designed that involves 10 time points for sleep processes. In ESPS, the 10 time points are calculated according to the allocated bandwidths in both the upstream and the downstream. The simulation results show that ESPS outperforms traditional Upstream Centric Scheduling (UCS) scheme in terms of energy consumption and the average delay for both real-time and non-real-time packets downstream. The simulation results also show that the average energy consumption of each ONU in larger-sized networks is less than that in smaller-sized networks; hence, our ESPS is better suited for larger-sized networks.     

Union-PON,全业务光纤接入解决方案

从Union-PON的网络结构、共存波分复用器、承载无线BBU-RRU间业务的WDM-PON模块等3个方面介绍了Union-PON的关键技术,并通过测试结果说明了Union-PON系统中的TDM-PON和WDM-PON在共存情况下互无干扰。     

OLT PON端口内置OTDR技术分析

摘要：伴随着“宽带中国”战略的推进,FTTx大规模部署,同时光纤故障检测需求越来越多,需要一种以较低成本实现PON故障检测,提高运维效率的解决方案。因此,研究了OLT PON端口内置OTDR 技术,分析比较了不同波长方案的实现和成本,重点提出了基于PON 端口内置OTDR 的PON 系统架构,给出PON 端口内置OTDR 技术的测试性能要求以及限制其对设备、通信业务影响的要求,从而使PON端口内置OTDR 能够满足运营商的PON运营检测需求,提高运维效率。     

PON接入网络测试系统建设的研究

宽带接入网络中引入PON接入方式后,传统测试系统已经无法支撑PON用户线路的故障定位。本文描述了一种在现有PONEMS系统之上的综合测试系统的研究与应用,在不改变现有维护模式的前提下,实现PON网络状态查询及自动故障诊断,PON网络进行例行的主动监测,PON网络业务开通竣工测试和告警信息收集处理功能,显著解决了末端维护人员在PON线路维护方面手段缺乏的问题,提高了工作效率,提升了客户的满意度。     

一种PON系统线路保护装置的研制

无源光网络(PON)系统普遍采用点到多点的树形拓扑结构,它的主干光纤的生存性问题关系到整个PON系统的可靠性,因此对主干光纤进行保护是非常必要的.文章介绍一种低成本并可自动切换的PON系统主干光线路保护装置(OLP-P),并用两个实验来验证OLP-P的自动倒换功能和倒换时间以及在PON系统中的自动倒换功能和倒换恢复时间.     

Bandwidth-efficient PON system for broad-band access and local customer Internetworking

We present a new passive optical network (PON) architecture for broad-band access and local customer networking. It provides high bandwidth efficiency for delivering both PON and customer internetworking services. The architecture separates the local optical network from the PON system, thereby enhancing security, flexibility, and allowing the use of any media access control protocol. The local customer internetworking feature is demonstrated with insignificant penalty to the overall PON system performance.