A Two‐Step Scheduling Algorithm to Support Dual Bandwidth Allocation Policies in an Ethernet Passive Optical Network

In this paper, we design a two‐step scheduling algorithm to support multiple bandwidth allocation policies for upstream channel access in an Ethernet passive optical network. The proposed scheduling algorithm allows us a simultaneous approach for multiple access control policies: static bandwidth allocation for guaranteed bandwidth service and dynamic bandwidth allocation for on‐demand, dynamic traffic services. In order to reduce the scheduling complexity, we separate the process of the transmission start‐ time decision from the process of grant generation. This technique does not require the timing information of other bandwidth allocation modules, so respective modules are free from a heavy amount of timing information or complex processing.     

基于改进离散蝙蝠算法的无线Mesh网络部分重叠信道分配

针对应急通信背景下无线Mesh网络(WMN)中存在的信道干扰和频谱资源利用不充分的问题,该文提出一种改进的离散蝙蝠算法(IDBA)用于求解最优部分重叠信道(POCs)分配方案。该方法采用K-means聚类算法优化网络拓扑,引入樽海鞘群的链式行为提高局部搜索能力,建立以最小化链路加权干扰为目标的线性规划模型来解决流量汇聚情况可能造成的网络瓶颈链路问题。仿真结果表明,在不同网络规模下,相比于其他基于群智能优化算法的信道分配方法,该方法具有较快的收敛速度和较优的搜索能力。此外,该方法能够在节点密集时显著降低网络干扰并保持网络的稳定性。     

高效全业务接入网——GPON

GPON具有高速率、高效率和低成本的特点，是实现宽带接入网的最佳技术之一。本文主要介绍了GPON的参考配置、媒质访问控制、GEM封装和DBA，最后结合GPON的优势论述了GPON在目前网络中的应用模式。     

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.     

在工业网中EPON的DBA算法研究

EPON系统中,上行数据传输的动态带宽分配（DBA）算法是关键技术之一。针对EPON在工业网络通信中的应用,对现有的DBA算法进行了分析和改进,以保证监控和报警等特殊业务的实时送达,消除交叉轮询的带宽浪费,并对该算法进行了仿真实验。仿真结果表明,该算法的带宽利用率高,业务时延抖动低,并且在低负载时无轻载惩罚现象。     

一种保证QoS的10G-EPON动态带宽分配算法

随着高清IPTV、在线游戏等业务的发展,用户对于带宽的需求日益增加,10G-EPON技术应运而生。与传统的EPON系统一样,10G-EPON系统的动态带宽分配问题仍然十分关键。带宽分配方式的选择对于如何避免传输冲突,提高系统的带宽利用率且保障服务质量都非常重要。在已有算法的基础之上,提出一种改进型动态带宽分配算法。该算法重点确保高优先级业务的服务要求,在一定程度上体现了不同等级ONU之间的公平性,提高了上行带宽利用率。     

Inter‐ONU Bandwidth Scheduling by Using Threshold Reporting and Adaptive Polling for QoS in EPONs

I dynamic bandwidth allocation (DBA) scheme, an inter–optical network unit (ONU) bandwidth scheduling, is presented to provide quality of service (QoS) to different classes of packets in Ethernet passive optical networks (EPONs). This scheme, referred to as TADBA, is based on efficient threshold reporting from, and adaptive polling order rearranging of, ONUs. It has been shown that the network resources are efficiently allocated among the three traffic classes by guaranteeing the requested QoS, adaptively rearranging the polling orders, and avoiding nearly all fragmentation losses. Simulation results using an OPNET network simulator show that TADBA performs well in comparison to the available allocation scheme for the given parameters, such as packet delay and channel utilization.     

BPON系统关键技术研究

在介绍宽带无源光网络(BPON)的结构、研究现状和发展趋势基础上,分析和研究了实现BPON的几种关键技术,包括BOPN系统的MAC层协议以及动态带宽分配(DBA)、测距、突发同步、突发发射与接收技术、ONT设计的关键技术、安全及搅动等技术的分析和理论研究,并提出了相应的解决方法.     

EPON系统多业务承载调度机制的研究

本文根据当前宽带多业务的需求,分析了EPON系统承载多业务的必要性,提出了衡量EPON系统调度机制优劣的因素.在介绍了两种现有调度机制工作原理的同时,根据各方面因素对这两种调度机制的优劣进行了分析,最后给出了EPON系统中这两种调度机制目前适用的网络场景.