【作者】 杨康；

【导师】 刘德明； 张敏明；

【作者基本信息】 华中科技大学 ， 电子科学与技术， 2011， 博士

【摘要】 无源光网络(PON, Passive Optical Network)技术是光接入网的主要解决方案之一,具有成本低、可靠性高、维护简单等优点。随着用户宽带业务需求的不断增长,现有EPON(Ethernet PON)和GPON(Gigabit PON)技术均难以满足业务长期发展的需求,因此发展下一代的无源光网络技术已成为国内外的研究热点。本论文从高带宽、长距离、大容量以及本地化组网等方面,对下一代无源光网络系统架构及其媒质接入控制(MAC, Media Access Control)协议进行了系统地研究,并对相关的动态带宽分配(DBA, Dynamic Bandwidth Allocation)算法进行了仿真与分析。主要研究成果如下：(1)针对各种树型无源光网络,提出了一种通用的网络建模与算法仿真的方法。主要基于Opnet Modeler仿真软件,实现了光线路终端(OLT, Optical Line Terminal)、光网络单元(ONU, Optical Network Unit)、业务源等节点模型,从而搭建了一个PON网络的仿真平台,为网络带宽分配算法的深入研究奠定了基础。(2)针对波分复用无源光网络(WDM-PON),提出了一种高效的带宽分配策略。在固定服务、限制服务、开门服务三种带宽分配策略下对Online算法的性能进行了测试,结果表明开门服务策略可以有效减小数据传输延时。(3)针对长距无源光网络(LR-PON),提出了一种基于流水周期轮询的动态带宽分配算法,能够有效消除周期间的调度间隙,降低数据包的端到端延时；并且能够有效支持各种不同等级的业务,特别是实时性较高的语音业务。(4)针对提供本地互联功能的副载波复用无源光网络,提出了分布式的多点接入协议和DBA算法。在所提算法下,各个ONU利用远端节点处3×N耦合器或者光纤布拉格光栅(FBG)对上行光信号的反射作用,实现光域的互联互通,从而使得整个带宽分配过程无需OLT介入,仅由各个ONU协调完成,从而有效降低了控制平面延时；另外所提算法在ONU处对局域网(LAN)业务与上行业务进行了分离,分别采用无线(RF, Radio Frequency)信号与基带信号进行同步传输,从而提高了上下行信道的可用带宽。(5)针对基于周期阵列波导光栅(AWG)的波分时分混合复用无源光网络(Hybrid WDM/TDM-PON),提出了物理子PON与逻辑子PON的概念；针对单个逻辑子PON,基于最早可利用时间调度机制,提出了两种动态带宽分配算法,从而有效地避免了资源竞争,实现了OLT与ONU之间的双向数据传输。更多还原

【Abstract】 Passive Optical Network (PON) has been one of the main solutions for optical access network, and has the advantages of low cost, high reliability and simple maintance. As users demand for broadband services is growing, the current EPON (Ethernet PON) and GPON (Gigabit PON) are difficult to meet the needs of long-term development, so the next-generation passive optical network technologies have become a research hotspot at home and abroad.This thesis systematically studied the architectures of next-generation PON systems and their media access control (MAC) protocols from the aspects of high bandwidth, long transmission distance, large capacity and local area networking;in addition, the related dynamic bandwidth allocation (DBA) algorithms were simulated and analyzed. The main results were as follows:(1) For varieties of tree-based passive optical network, a general method for network modeling and algorithm simulation was proposed. By using Opnet Modeler simulation software, the node-level models of optical line terminal (OLT), optical network unit (ONU), traffic source and others were realized, and then a PON simulation platform was built, which laid a foundation for the further research of bandwidth allocation algorithm in PON systems.(2) For wavelength division multiplexed passive optical network (WDM-PON), an efficient bandwidth allocation strategy was proposed. The online algorithm was realized and tested with three bandwidth allocation strategies which were fixed service, limited service and gated service respectively. The results show that the open service strategy can effectively reduce the data delay.(3) For long-reach PON (LR-PON), a pipelined cyclic dynamic bandwidth allocation algorithm was proposed, which not only reduces the packet end-to-end delay by eliminating scheduling gaps between the cycles, but also provides better supports for different grades of traffic, especially for the real-time voice service.(4) For subcarrier multiplexed passive optical network supporting local area networking, a distributed multipoint access protocol and DBA algorithm were proposed. Under the proposed algorithm, ONUs communicated with each other by the help of 3×N coupler or Fiber Bragg Grating (FBG) at remote node which reflects the up-transmission optical signals. The process of bandwidth allocation was completed coordinately by the ONLUs without the intervention of OLT, which effectively reduces the control plane delay. In addition, LAN traffic and upstream traffic were separated form each other at ONUs and transmitted synchronously in RF (Radio Frequency) and baseband signals respectively, which increases the available bandwidth of up-link and down-link channel.(5) For hybrid WDM/TDM-PON based on periodical waveguide array grating (AWG), the conceptions of physical sub-PON and logical sub-PON were presented; and for logical sub-PON, two kinds of DBA algorithms adopting earliest available time scheduling mechanism were proposed, which effectively avoids the resources competition and achieves bidirection transmissions between OLT and ONU.更多还原