Mini‐Slot‐Based Transmission Scheme for Local Customer Internetworking in PONs

We propose a new mini‐slot transmission scheme for a passive optical network (PON) in which each customer can be switched either to access mode or to internetworking mode dynamically. In this paper, we present the system implementation (called LAN‐PON) as well as the performance of the proposed transmission scheme to illustrate its feasibility and benefits. A mini‐slot scheme can rapidly reduce the queuing delay, which increases due to the flooding of the deflected packets in a deflection scheme. We evaluate the impact of mode switching time on the bandwidth gain (throughput) and delay of local area network (LAN) traffic in the LAN‐PON with a mini‐slot scheme. We also analyze a theoretical delay model of the proposed scheme. The simulation results demonstrate that switching time has an impact on LAN performance, and the average packet delay of the proposed scheme is significantly improved compared to that of the deflection scheme.     

Passive optical networks for local telephony and cable TV provision

Recent proposals have been made for a passive optical local access network (PON) for telephony and cable TV applications. These are leading to the design of new telecommunications customer access equipment whose functional requirements are discussed, together with details of the system demonstrators at BTRL. Possible sccenarios for network deployment are presented.     

Experimental demonstration of remote unified control for OpenFlow-based software-defined optical access networks

Passive optical network (PON) has attracted much attention by the emergence of high-bitrate video-centric applications over the Internet in the access side. In the current commercial PON, the configuration of optical line termination equipment is needed to modify through network management system manually and periodically in the local areas. The traffic flow of different users lacks dynamic control and intelligent schedule. In this paper, we propose and implement a novel software-defined optical access network (SDOAN) architecture for remote unified control based on OpenFlow-enabled PON. Based on the proposed architecture, a service-aware flow scheduling strategy is introduced to flexibly and efficiently allocate the network bandwidth resources and detect the status of network flows in real time. The SDOAN can enhance the resource utilization and QoS guarantee of each user effectively through unified control manner, and reduce the operating expense by remote interaction and operation. We have designed and verified experimentally SDOAN on our test bed with OpenFlow-enabled OLTs. The overall feasibility and efficiency of the proposed architecture are also experimentally demonstrated and compared with interleaved polling with adaptive cycle time strategy in terms of resource occupation rate and average delay.     

PON接入技术在城域网中的应用定位

光接入是宽带接入的发展方向,无源光网络(PON)是实现光纤到户(FTTH)的首选方案.本文首先分析了城域网概念的引入对接入网发展的影响和PON接入网的原理特点,指出PON拓扑结构完全符合城域网边缘的业务汇聚和接入模式,符合城域网概念引入后的用户业务引入段和接入层的结构特点,最后给出了PON技术与MSTP(多业务传送平台)结合构建多业务城域网的策略和PON技术在移动网络中的应用定位.     

Self-Healing Ring-Based Time-Sharing Passive Optical Networks

A new ring-based time-shared passive optical network (PON), with a self-healing function to prevent the occurrence of fiber-fault, has been proposed and investigated experimentally. By using the new optical line termination and single fiber path architecture, the proposed self-healing ring topology PON can be revived promptly under single fiber failure. The system performances of the proposed access network are also measured and discussed.     

Novel schemes for local area network emulation in passive optical networks with RF subcarrier multiplexed customer traffic

This paper proposes two novel optical layer schemes for intercommunication between customers in a passive optical network (PON). The proposed schemes use radio frequency (RF) subcarrier multiplexed transmission for intercommunication between customers in conjunction with upstream access to the central office (CO) at baseband. One scheme employs a narrowband fiber Bragg grating (FBG) placed close to the star coupler in the feeder fiber of the PON, while the other uses an additional short-length distribution fiber from the star coupler to each customer unit for the redirection of customer traffic. In both schemes, only one optical transmitter is required at each optical network unit (ONU) for the transmission of customer traffic and upstream access traffic. Moreover, downstream bandwidth is not consumed by customer traffic unlike in previously reported techniques. The authors experimentally verify the feasibility of both schemes with 1.25 Gb/s upstream baseband transmission to the CO and 155 Mb/s customer data transmission on the RF carrier. The experimental results obtained from both schemes are compared, and the power budgets are calculated to analyze the scalability of each scheme. Further, the proposed schemes were discussed in terms of upgradability of the transmission bit rates for the upstream access traffic, bandwidth requirements at the customer premises, dispersion tolerance, and stability issues for the practical implementations of the network.     

Low-cost and scalable passive optical network architecture using remote repeater

We report a new passive optical network (PON) architecture to reduce customer transmitter cost using an upstream repeater at the remote node. The system can further provide both downstream and upstream regeneration by utilising standard bidirectional transceivers. Our architecture can extend a conventional PON's feeder fibre reach to 50 km and split ratio to 1:256. The system demonstration shows insignificant penalty to the existing network performance and meets the IEEE 802.3ah standard requirements.     

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)。     

MPCP based active optical access network with PLZT high-speed optical switch

An active optical access network architecture with our newly developed PLZT ((Pb,La)(Zr,Ti)O₃) high-speed optical switch is introduced, with a view to realizing the next-generation high capacity scalable access network. This system is developed based on the latest IEEE standard of PON (10G-EPON; IEEE802.3av) in consideration of the coordination with future high capacity PON. PLZT high-speed optical switches are able to switch an optical signal at nano-second speed (<5-10 ns). Generally, the merits of using optical switches are increasing the number of subscribers and transmission distance easily, preventing malicious ONUs from interfacing with the communication between OLT and the other ONUs, realizing fast fiber and OLT protection/restoration and providing various services by controlling optical switches dynamically. This paper focuses on two key technologies; a PLZT optical switch and a new discovery process for active optical access network based on MPCP defined at IEEE802.3. A major challenge in designing active optical access network is supporting the discovery process of MPCP because it does not offer broadcast transmission unlike the regular PON. We propose here a new discovery process; it has been tested successfully in an implementation of our proposed system.     

IP/ATM integrated services over broadband access coppertechnologies

A rich set of broadband access copper technologies is available in the market today, and more are coming out of the laboratories, rapidly moving to standardization. The most likely future scenario will be one where many different technologies coexist. This multi-access-technology paradigm poses an interesting internetworking problem where interoperability and capability to support today's and future user services play a major role in the design of a network architecture. This article begins with an overview of current and new xDSL access technologies to continue describing an access network design that harmonizes the interconnection between PON, xDSL, and native ATM transport technologies. The use of ATM technology for the interface to the broadband access and transport networks is then presented and justified. The article continues studying the protocol architectures proposed for access to network service providers, considered a driver application for broadband access deployment. Finally, different protocol architectures that can provide integrated services support at the user equipment are analyzed     

一种应用于EPON的新型保护环和分区保护子环结构

以太无源光网络(EPON)是下一代宽带接入网的一种可行方案,为了增强网络的生存性,ITU-T G.983.1定义了几种无源光网络(PON)保护结构.在此基础上,文章提出了一种应用于EPON的新型保护环结构和分区保护子环结构,研究了其保护机制,分析了倒换时间,估计保护时间小于14ms.     

Broadband upgrade of an operating narrowband single-fiber passiveoptical network using coarse wavelength division multiplexing andsubcarrier multiple access

We demonstrate an overlay of a broadband passive optical network (PON) on the same fiber network as an operating baseband digital system. The baseband system is modeled after current-generation narrowband PONs, and the two PONs can be operated simultaneously. The broadband PON incorporates coarse wavelength division multiplexing to increase the downstream bit rate, and subcarrier multiple access for the upstream upgrade. We examine the RF interference between baseband and subcarrier signals, and provide guidelines on channel spacing and means for accommodating differing power levels for the two signals. The broadband architecture described here provides a graceful upgrade path for providing advanced digital services on a PON without having to modify the network or terminal equipment used for providing narrowband services     

Architecture of multi-OLT PON systems and its bandwidth allocation algorithms

In this paper, we propose a novel passive optical network (PON) architecture that has multiple optical line terminals (OLTs). Unlike existing PONs where all ONUs are connected to a single OLT, the proposed multi-OLT PON allows subscribers to choose their own service providers from among multiple OLTs. Service companies and subscribers can make service level agreements (SLA) on the amount of bandwidth that each OLT or ONU requires. A new control protocol and bandwidth allocation algorithms appropriate in this new PON environments are suggested. For the downstream, a scheme to share the bandwidth among multiple OLTs is studied to maximize the total transmitted packets while guaranteeing each OLT’s SLA. A modified Limited Dynamic Bandwidth Allocation named mLimited scheme is also proposed for upstream transmission toward multiple OLTs, which maximizes the total upstream throughput while minimizing the delay of each ONU. Performances of the proposed PON architecture and algorithms are analyzed. A PON system with two OLTs and 16 ONUs is used in the analysis. Self-similar traffic reflecting current packet distribution is used in the packet generation. The results show that the proposed DBA schemes efficiently manage bandwidth even when the occurred traffic load is quite different from the reserved bandwidth. It is found that the proposed PON architecture is appropriate in supporting diverse services in future high-speed optical access network.     

以太无源光网络技术及其系统设计

近几年出现的以太无源光接入网(EPON)技术结合了成熟的以太网技术和高带宽的PON技术,已成为接入网技术的最新发展方向.本文主要介绍了EPON的基本设计及其优势,提出了具体应用中要注意的若干问题,为实际系统的设计提供了相应的参考.     

宽带光纤接入网及其发展展望

文章指出各种宽带光纤接入网都有其最佳使用场合和时机,宽带点到点有源光纤系统最适合企事业用户;宽带点到点有源以太网光纤系统适合在低密度用户分散地区应用;宽带点到多点无源光纤系统最适合新建或改建的密集用户区应用.文章认为中国宽带光纤接入网的发展将可能跨越ATM无源光网络(APON)、宽带无源光网络(BPON)和以太网无源光网络(EPON)阶段,从宽带点到点以太网光纤系统和千兆比特以太网无源光网络(GEPON)开始,较快地过渡到千兆比特无源光网络(GPON).     

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。     

Implementation of a TDM passive optical network for subscriber loopapplications

An experimental prototype system for subscriber loop applications that has been implemented using a passive optical network architecture is described. The system, known as MACNET, uses time-division multiplexing and transmission over a network of single-mode optical fibers and couplers to provide narrowband digital service access to 16 customers. Experience gained from developing the system is outlined. Future transmission options, including a fixed-bit-rate customer access approach to allow early network application of this technology, are described     

基于光纤无线融合的射频无源光网络

文章认为为了实现更大的光接入网容量,并能更好地完成多业务的承载与融合,亟待发展下一代光接入网技术。文章提出了基于光纤无线融合的射频无源光网络(RPON),其不仅具有现有无源光网络系统低成本和易管控的特点,还具备光载射频系统灵活度高和移动性好的优势。该系统通过光生毫米波和波分复用的方式,实现了1Gb/s多媒体业务的单纤上下行传输,达到了10km光纤和5m无线的接入距离,能够满足低成本化推广应用要求。     

A novel medium access control protocol for passive optical network supporting local area networking capabilities

An alternate solution for Ethernet passive optical networks (EPON) providing local area networking (LAN) capabilities is proposed in this article. Our solution adopts a star coupler-based PON architecture and uses radio frequency subcarrier multiplexed transmission for the LAN traffic delivery. The proposed medium access control (MAC) protocol supports a fully distributed control plane among the optical network units (ONUs) for ONU–ONU communication as well as upstream access to the OLT. The simulation results indicate that the proposed MAC protocol outperforms the others in terms of the average packet end-to-end delay, especially for LAN traffic.     

A novel medium access control protocol for WDM-based LAN's andaccess networks using a master/slave scheduler

We describe an architecture and medium access control (MAC) protocol for wavelength-division multiplexing (WDM) networks. Our system is based on a broadcast star architecture and uses an unslotted access protocol and a centralized scheduler to efficiently provide bandwidth-on-demand in WDM networks. To overcome the effects of propagation delays the scheduler measures the delays between the terminals and the hub and takes that delay into account when scheduling transmissions. Simple scheduling algorithms, based on a look-ahead capability, are used to overcome the effects of head-of-line blocking. An important application area for this system is in optical access networks, where this novel MAC protocol can be used to access wavelengths in a WDM passive optical network (PON)