Development of Efficient Dynamic Bandwidth Allocation Algorithm for XGPON

This paper proposes an efficient bandwidth utilization (EBU) algorithm that utilizes the unused bandwidth in dynamic bandwidth allocation (DBA) of a 10‐gigabit‐capable passive optical network (XGPON). In EBU, an available byte counter of a queue can be negative and the unused remainder of an available byte counter can be utilized by the other queues. In addition, EBU uses a novel polling scheme to collect the requests of queues as soon as possible. We show through analysis and simulations that EBU improves performance compared to that achieved with existing methods. In addition, we describe the hardware implementation of EBU. Finally we show the test results of the hardware implementation of EBU.     

一种改进的GPON动态带宽分配策略

利用小波变换将自相似性网络流量的长相关性转化为短相关性,并预测流量的方法,对GPON系统物理媒质控制(MAC)层的关键技术--动态带宽分配(DBA)进行研究.在理论上对一种已有的DBA策略提出合理改进.     

LR-PON中改进的节能动态带宽分配算法

长距离无源光网络(Long-reach Passive Optical Networks,LR-PON)的覆盖范围超过100 km,光网络单元(Optical Network Units,ONU)在一个轮询周期中处于空闲状态的时间较长.如果使处于空闲状态的ONU进入低功耗(休眠或假寐)模式,可以降低ONU的能耗.基于此,文章提出一种改进的节能动态带宽分配算法.该算法通过改变ONU的调度顺序,使得ONU在上下行传输结束后能够立刻进入休眠状态,而无需等待授权帧的到达,从而延长ONU的休眠时间.仿真结果表明:所提出算法能够降低ONU能耗和下行数据包平均时延.     

基于EPON的公平带宽分享算法及其应用

考虑光学开放接入网（optical open access network）中的公平性,将最大最小公平算法用到双向服务等级协议（D-SLA）中,提出了一种基于以太无源光学网络（EPON）的易于实现的双向服务等级协议公平带宽分配算法。算法使用了两轮分配,通过分级管理确定首要SLA和次要SLA,对业务提供商和用户进行分级区...     

GPON的MAC协议设计

参照ITU T建议草案:吉比特无源光网络传输汇聚层规范(G.GPON.gtc),提出了一种支持分组业务接入的媒质接入控制(MAC)协议.通过仿真建模对该协议的性能进行了分析.     

新颖的WDM EPON动态带宽调度算法

对WDM EPON的ONU授权调度技术进行了研究,采用调度理论的方法来解决授权调度问题。将授权调度和波长分配进行结合,并将其形式化为矩形Packing问题,采用拟人的策略,提出了基于欧氏距离的高效用ONU带宽分配策略,为WDM EPON中ONU授权调度问题的快速求解提供了一种高效的启发式算法。进一步模拟实验表明,提出的算法可以减少平均分组时延,提高网络带宽利用率,表明算法对授权调度的有效性。     

Technology for extending transmission distance of EPON system

At present, the maximal transmission distance between the optical line terminal (OLT) and opticalnetwork unit (ONU) of an Ethemet passive optical network (EPON) system is 20 km.However, this distance should be extended to 50 km or even longer in some applications such as fiber to the village (FTTV).A method for extending the transmission distance of an EPON system is proposed in this paper, in which the optical power amplifier and the adjustment of dynamic bandwidth allocation (DBA) are the key technologies.     

Network coding based joint signaling and dynamic bandwidth allocation scheme for inter optical network unit communication in passive optical networks

As an innovative and promising technology, network coding has been introduced to passive optical networks (PON) in recent years to support inter optical network unit (ONU) communication, yet the signaling process and dynamic bandwidth allocation (DBA) in PON with network coding (NC-PON) still need further study. Thus, we propose a joint signaling and DBA scheme for efficiently supporting differentiated services of inter ONU communication in NC-PON. In the proposed joint scheme, the signaling process lays the foundation to fulfill network coding in PON, and it can not only avoid the potential threat to downstream security in previous schemes but also be suitable for the proposed hybrid dynamic bandwidth allocation (HDBA) scheme. In HDBA, a DBA cycle is divided into two sub-cycles for applying different coding, scheduling and bandwidth allocation strategies to differentiated classes of services. Besides, as network traffic load varies, the entire upstream transmission window for all REPORT messages slides accordingly, leaving the transmission time of one or two sub-cycles to overlap with the bandwidth allocation calculation time at the optical line terminal (the OLT), so that the upstream idle time can be efficiently eliminated. Performance evaluation results validate that compared with the existing two DBA algorithms deployed in NC-PON, HDBA demonstrates the best quality of service (QoS) support in terms of delay for all classes of services, especially guarantees the end-to-end delay bound of high class services. Specifically, HDBA can eliminate queuing delay and scheduling delay of high class services, reduce those of lower class services by at least 20%, and reduce the average end-to-end delay of all services over 50%. Moreover, HDBA also achieves the maximum delay fairness between coded and uncoded lower class services, and medium delay fairness for high class services.     

Review on Dynamic Bandwidth Allocation of GPON and EPON

The passive optical network (PON) technology has been drastically improved in recent years. In spite of using the optical technology, the utilization of the entire bandwidth is a very challenging task. The main categories of PON are the Ethernet passive optical network (EPON) and gigabit passive optical network (GPON). These two networks use the dynamic bandwidth allocation (DBA) algorithm to attain the maximum usage of bandwidth, which is provided in the network dynamically according to the need of the customers with the support of the service level agreement (SLA). This paper will provide a clear review about the DBA algorithm of both technologies as well as the comparison.     

EPON动态带宽分配算法研究

文章针对EPON上行多路访问机制,提出了一种新的动态带宽分配算法:动态最大访问窗口(DMTW)算法.给出了模型和仿真结果,证明了这种算法的正确性和优势.     

基于QoS的EPON系统动态带宽分配机制

通过阐述以太网无源光网络（EPON）系统信道传输数据方式以及动态带宽分配的工作原理,进一步研究了动态带宽分配算法（DBA）在EPON系统中的应用。提出一种基于服务质量（QoS）的EPON系统动态带宽分配机制,该机制根据不同业务的优先级和动态带宽分配算法,灵活地分配上行带宽,提高了带宽利用率,改善了服务质量。     

Energy-efficient dynamic wavelength and bandwidth allocation algorithm with delay constraint for time and wavelength division multiplexed passive optical networks

Based on offline scheduling and node modular design,an energy-efficient dynamic wavelength and bandwidth allocation algorithm with the delay constraint (EE-DWBA-DC) was proposed.Optical line terminal (OLT) and optical network units (ONU) were considered to save energy.Under the constraint of packet delay,the number of active wavelengths could be reduced as much as possible and the length of polling cycle was increased.At the same time,the uplink and downlink transmission time of OLT and ONU were concentrated to reduce the state conversion times and extend its low-power duration.In addition,the high energy consumption voids of channels were attempted to be minimized.The simulation results verify that the proposed algorithm can reduce the energy consumption of OLT and ONU and the total energy consumption of the whole network under the premise of guaranteeing packet delay constraints.     

Decentralized DBA scheme based on power detection in TDM-PON

In this article, we propose a new decentralized hardware-based DBA scheme in TDM-PON. Of particular significance in the proposed scheme is that the bandwidth of the uplink data transmission is dynamically allocated to each ONU without the intervention of the OLT. In this way, software-based DBA processing can be eliminated in the OLT and ONUs, resulting in the simple, fast, and cost-effective operation of the DBA in TDM-PON. The performance of the proposed scheme was evaluated by performing a statistical analysis and numerical analysis of the average packet end-to-end delay. We confirmed the superior performance of the proposed scheme by comparing the results obtained for this technique with those of other EPONs.     

EPON和WiMAX融合网管带宽管理模块设计实现

在EPON和WiMAX融合接入网中,为对网络带宽进行管理,需要结合WiMAX业务在EPON网络中的映射情况,对各级带宽进行配置.针对这一需求,设计实现了能够自动对带宽进行重新分配的带宽管理模块.该模块具有友好的图形化操作界面和合理的带宽配置算法.采用了典型的C/S结构进行模块划分和设计,利用Java语言结合NetBeans等工具完成了具体功能的实现.     

采用动态带宽提高技术的用于无源超高频RFID标签的供电系统

This paper presents a voltage regulator system for passive UHF RFID transponders,which contains a rectifier,a limiter,and a regulator.The rectifier achieves power by rectifying the incoming RF energy.Due to the huge variation of the rectified voltage,a limiter at the rectifier output is used to clamp the rectified voltage.In this paper,the design of a limiter circuit is discussed in detail,which can provide a stable limiting voltage with low sensitivity to temperature variation and process dispersion.The key aspect of the voltage regulator system is the dynamic bandwidth boosting in the regulator.By sensing the excess current that is bypassed in the limiter during periods of excess energy,the bias current as well as the bandwidth of the regulator are increased,the output supply voltage can recover quickly from line transients during the periods of no RF energy to a full blast of RF energy.This voltage regulator system is implemented in a 0.18 μm CMOS process.     

Efficient medium arbitration of FSAN‐compliant GPONs

The steadily rising demand for multimedia and data services, the falling cost and omnipresence of Ethernet and the maturity of passive optical networks (PON) technology, promise to radically change the landscape in the local loop. The heart of a gigabit PON system (recently standardized by FSAN/ITU) is the medium access controller (MAC), which arbitrates access to the upstream link among users with fluctuating traffic demands and effects the multiplexing and concentration policy. At the same time, it has to safeguard the service quality and enforce the parameters agreed in the service level agreements (SLAs) between the users and the service provider. In this paper, a MAC protocol designed to serve any mix of services according to their quality of service (QoS) needs, employing four priority levels along with a high number of logically separate data queues is presented. The architecture and implementation in hardware of a MAC algorithm capable of allocating bandwidth down to a resolution of a byte with QoS differentiation is the focus of this paper. It employs the bandwidth arbitration tools of the FSAN/ITU G.984.3 standard and maps SLA parameters to GPON service parameters to create an efficient, fair and flexible residential access system. Copyright © 2005 John Wiley & Sons, Ltd.     

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.     

Interleaved Polling with Adaptive Cycle Time (IPACT): A Dynamic Bandwidth Distribution Scheme in an Optical Access Network

While in recent years backbone bandwidth has experienced substantial growth, little has changed in the access network. Last mile still remains the bottleneck between a high capacity LAN or home network and the backbone. Passive optical network (PON) is a technology viewed by many as an attractive solution to this problem.In this study, we discuss and evaluate design issues for PON access networks. Specifically, to drive the cost of an access network down, it is very important to have an efficient, scalable solution. We believe that a PON based on polling, with data encapsulated in Ethernet frames, possesses the best qualities, such as dynamic bandwidth distribution, use of a single downstream and a single upstream wavelength, ability to provision a fractional wavelength capacity to each user, and ease of adding a new user.To support dynamic bandwidth distribution, we propose an interleaved polling algorithm. We then suggest a scheme for in-band signaling that allows using a single wavelength for both downstream data and control message transmission.To obtain realistic simulation results, we generated synthetic traffic that exhibits the properties of self-similarity and long-range dependence. We then analyzed the network performance and its effect on various types of traffic, e.g., best-effort data traffic, VBR video traffic and CBR streams.     

无源光网络技术及其应用市场(本期优秀论文)

着重介绍国内外的APON、EPON和GPON三种PON(passive optical network)技术的研发进展情况,并提及用于未来全光接入网的两种新型PON技术:WDM-PON和WDM/OCDMA-PON技术,以便使人们展望未来的PON技术的发展方向.同时,文章还介绍国内外对APON,EPON和GPON三种PON技术的应用市场开发情况.最后介绍如何结合我国国情来开发PON技术应用市场,并列举了一些有借鉴意义的应用开发实例.