A midterm DBA algorithm for quality of service on aggregation layer EPON networks

This work presents a new approach on dynamic bandwidth allocation (DBA) for Ethernet Passive Optical Networks (EPONs). A brief introduction to the DBA area and major term definitions are given. The related research and standardization efforts are presented. Justification that EPONs can be used on the aggregation network is provided, based on their evolution and related research proposals. Focus is given to the Long Reach-Passive Optical Networks (LR-PONs) and their limitations which show the need for a non-polling, midterm DBA scheme for next-generation EPONs. The challenges arising, because of this new approach, are discussed along with possible solutions. Finally, this work proposes the EMDBA algorithm which is able to overcome the discussed issues. The correct operation of this algorithm is confirmed by a set of simulations using OMNet++ framework, and the outcome results show that EMDBA performance is satisfactory in terms of delay and service differentiation.     

一种多业务接入的EPON动态带宽分配算法

EPON以其各方面的优点即将成为接入网的主流技术,但现有的EPON上行链路动态带宽分配算法还有很多不足之处。对结合EPON中的算法对现有的算法进行了改进,提高了带宽利用率和时延抖动。在对MAC进行描述的基础上进行了EPON系统仿真模型,结果表明：改进后的算法具有较高的带宽利用率和较EF业务时延抖动,与此同时,也明显降低了AF、BE业务的队列时延抖动。     

一种在EPON中支持多业务接入的DBA公平算法

上行带宽的动态带宽分配是以太网无源光网络(EPON)系统的一个重要研究领域,文章提出了一种区分业务优先等级的动态周期轮询算法.该算法保证了高优先级业务的实时传输,同时为中、低优先级业务提供了基本的带宽,兼顾了动态带宽分配的效率和公平性.文中通过公式推导,给出了算法的具体实现过程,从理论上证明了新算法的可行性.     

EPON上行信道中的动态带宽分配算法研究

传统的EPON系统的上行动态带宽分配方案是类似于IPACT的基于时隙长度分配的,这样虽然使上行信道得到了充分的利用,但是由于包延迟变化较大,不适合实时业务的传送.文章提出了一种多级授权分离发送动态带宽分配算法,它可以为不同业务提供不同的服务质量,既满足了实时业务的需要,又在一定程度上提升了网络的利用率.通过仿真测试,发现这种算法均有良好的时延特性和较稳定的队列尺度,能较好地支持多业务优先级的EPON系统.     

EPON中一种有效的动态带宽分配算法的设计

提出一种有效的动态带宽分配算法Ⅰ-EBA,仿真试验表明,当网络负载很大时,Ⅰ-EBA算法在平均包延时和吞吐量方面的性能均要优于已有的EBA算法.     

EPON中一种改进的动态带宽分配算法的设计

动态带宽分配是EPON系统的关键技术之一.文章首先分析了一种基于IPACT的RR算法的,然后提出一种有效的动态带宽分配算法MLQF.仿真试验表明,当网络负载很大时,MLQF算法在平均包延时和平均队列长度方面的性能均要优于已有的RR算法.     

EPON中的一种新型动态带宽分配算法

动态带宽分配是以太网无源光网络(EPON)系统中的一个重要研究领域,提出了一种基于业务的两层三次带宽分配的DBA新型算法.该算法在兼顾动态带宽分配的带宽利用率和QOS保证方面进行了改进,通过研究分析给出了最优算法,并在模拟流量下进行了性能分析.通过与已有算法的对比,证明其有很好的性能.     

基于最小均方差预测的多队列调度EPON DBA

针对以太网无源光网络(EPON)系统中上行链路的时分复用机制,提出了一种基于最小均方差预测的多队列调度动态带宽分配(DBA)算法.仿真结果表明,该算法可以准确地预测高优先级业务的流量,根据预测结果再合理分配带宽,从根本上避免了轻载惩罚,减小了高优先级业务的延迟.     

一种保证EPON中DBA公平性的算法

动态带宽分配是以太网无源光网络(EPON)系统的一个重要研究领域,文章提出一种在EPON系统中保证动态带宽分配公平性的新型算法.该算法计算量适中, 同时兼顾了动态带宽分配的效率和公平性.文中通过推导给出了最优算法,并在模拟流量下进行了仿真,通过与已有算法的对比,证明其有很好的性能.     

一种支持多用户SLA的EPON上行带宽分配算法设计

在接入网服务等级协定的基础上,分析了以IPACT和CyclicDBA为代表的EPON上行动态带宽分配算法,讨论了其对EPON上多用户SLA支持所存在的固有缺陷。提出了适合SLA应用的EPON控制帧结构:授权帧和请求帧。根据这两种控制帧,设计了一种新型的支持多用户SLA的EPON上行信道带宽分配算法,等级轮询固定周期算法。通过理论分析和计算机仿真测试表明该算法针对EPON不同类型的接入用户均达到了较理想的性能指标,高优先级业务良好的时延和时延抖动特性,各种业务队列的尺度平稳,同时HPFCT还解决了传统轮询算法中低负载时下行带宽浪费明显的问题。     

Adaptive polling algorithm to provide subscriber and service differentiation in a Long-Reach EPON

A novel interleaved polling algorithm for Long-Reach EPONs is proposed in order to simultaneously provide subscriber and class of service differentiation. It is demonstrated that the new polling algorithm applied to a typical 100 km Long-Reach EPON performs better than centralized methods, where bandwidth prediction is needed to overcome the higher round trip time in which ONUs cannot transmit. As polling methods in Long-Reach EPONs do not require prediction, they are much simpler and show less computational complexity than centralized schemes, avoiding the inaccuracy of bandwidth prediction. Simulation results show that the new algorithm increases the achieved throughput when compared to centralized algorithms with traffic prediction, obtaining a significant reduction of both mean packet delay and packet loss ratio for the highest priority service level profiles.     

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.     

一种公平的EPON动态带宽分配算法

提出一种EPON上行链路动态带宽分配算法一周期比例DBA。ONU基于多门限周期地上报带宽请求，OLT根据ONU的带宽请求及其合约带宽进行动态带宽分配。当多个ONU竞争系统带宽时，OLT按照ONU合约带宽的比例进行带宽分配。仿真结果表明：周期比例DBA算法在实现高带宽利用率的同时又具有良好的公平性。     

A programmable optical network testbed in support of C-RAN: a reliability study

With both mobile network services and related data traffic volume on the rise, reliability of the radio access network is of the essence. A number of radio functional splits are defined by 3GPP to offer increased flexibility of implementation and feasibility of new mobile network services. For example, it is possible to implement certain radio functions in the Cloud, an architectural solution referred to as C-RAN. C-RAN solutions require highly reliable backhaul and fronthaul network designs. This paper describes PROnet, a programmable optical software-defined network testbed, which has been upgraded to offer backhaul and fronthaul transport capabilities in support of C-RAN functionalities with increased reliability. The testbed is upgraded with a specially designed 1 + 1 protection mechanism at the Ethernet layer in order to meet the stringent network round-trip requirements imposed by one of the C-RAN functional split options on the fronthaul.

     

一类基于网络服务品质要求的单播路由算法

本文提出了一类基于网络服务品质QoS（quality of service）要求的单播路由算法。首先,我们给出了基于网络分组调度机制WFQ的延迟和带宽相耦合的分析模型,从而推导出了最佳端到端通信延迟的上界。基于该模型,我们改造了传统最小跳数和最短延迟的两类路由算法以支持实时通信的服务品质要求。此外,我们还给出了两种新的服务品质路由算法,它们是多路径第k条最短延迟路由算法以及组合带宽和跳数（hop counts）的最大能量路由算法。仿真实验结果表明,四种算法尤其是后两种算法在满足用户带宽、延迟服务要求以及增加网络资源使用效率和网络吞吐率等方面各有特色。     

Packet Delay Analysis of Symmetric Gated Polling System for DBA Scheme in an EPON

In this paper, we analyze the mean packet delay of a dynamic bandwidth allocation (DBA) scheme in an Ethernet passive optical network (EPON). We propose the interleaved polling system with a gated service discipline and a two-stage queue in order to investigate the delay performance of DBA scheme in an EPON. We assume that input packets arrive at an optical network unit (ONU) according to a Poisson process from several types of users. We use a continuous time queueing model in order to find the mean packet delay and the mean cycle time of an arbitrary packet. We obtain the closed form solution for the mean packet delay of the proposed gated polling system with a two-stage queue. We obtain another result on the mean packet delay by solving a system of linear equations derived from the moments of the queue length distribution. We give some numerical results to investigate the delay performances for the symmetric polling system with statistically identical stations. In addition, we compare numerical results on the closed form solution with numerical results on a system of linear equations.     

A UNIVERSAL ALGORITHM OF MODULATION AND DEMODULATION

A new universal algorithm of modulation and demodulation is presented to process most signals of digital phase-related modulation schemes such as M-DPSK, MSK and even some M-FSK with low modulation level. It can easily deal with modulation and demodulation of the signals with different modulation schemes and data rates by only setting a few input arguments of the versatile software modules. The computational complexity of the algorithm is far less than that of conventional methods. The average processing capacity of the algorithm is about 15 instructions per symbol when processing DQPSK signals. It can be applied to software radios.     

支持多业务预测机制的EPON动态带宽分配算法

针对IPACT算法中存在较严重的轻载惩罚现象,提出了一种支持多业务预测机制的动态带宽分配算法(eIPACT算法).通过估计两个连续轮询之间的不同业务分组的到达量,并给ONU授权额外的带宽,减少了ONU分组中的等待时间和缓存占用.采用多业务优先级调度策略,不仅能避免轻载惩罚还可以保证系统的服务质量.结果表明,该算法既极大...     

基于多业务预测的EPON动态带宽分配算法

针对EPON系统中上行链路的时分复用机制,提出了一种支持流量预测与预分机制的动态带宽分配算法(PEM-DBA).该算法能够对高优先级业务进行流量预测,并根据预测结果预先分配带宽.仿真结果表明,该算法能在保障高优先级业务优的同时,降低数据时延,提高带宽的利用率.     

下行信道质量受控反馈算法与调度算法的研究

该文先介绍了在第三代移动通信技术体制cdma2000 1xEV-DO/DV中的下行信道质量反馈机制;然后提出了一种新的反馈控制算法,并结合一种综合考虑吞吐量和公平度的调度算法(正比公平调度算法)进行了分析与仿真。通过与未采用该策略的调度算法结果相比较,显示了新的算法在保持公平度的条件下能够提高系统吞吐量,同时减少了移动台的功耗,这种新的算法应用灵活,其策略对其它需要对共享资源调度的领域也有意义。