| Summary: | 博士 === 國立成功大學 === 電腦與通信工程研究所 === 102 === This dissertation is aimed at addressing critical issues in the optical-based access networks including of Short-Reach Ethernet Passive Optical Networks (SR-EPONs), Long-Reach EPONs (LR-EPONs), and Integrated EPON/Broadband Wireless Access Networks (BWANs).
The first part of the dissertation is to discuss the issue of supporting private networking over the optical-based access networks. It is known that the tree-based EPONs have been regarded as a cost-effective network architecture for easily implementing and achieving the broadcast transmissions. However, the tree-based EPONs are not suitable for realizing the point-to-point transmissions (or called private networking) since the signal path is only restricted between the Optical Line Terminal (OLT) and the Optical Network Units (ONUs). In order to support the private networking in the optical-based access networks, the current dissertation proposes new network architectures to achieve the private networking in the tree-based EPONs. Furthermore, the corresponding Dynamic Bandwidth Allocation (DBA) schemes are proposed to fully utilize the network bandwidth. Meanwhile, the corresponding analytical frameworks are proposed to investigate the proposed DBA schemes. The analytical and simulation results are found to be in good agreement with each other.
The second part of the dissertation is to investigate the so-called triple-play services (Voice over IP, video and BE traffic) in the EPON-based access networks. Since the conventional EPONs perform poorly in supporting differentiated services and therefore fail to meet the Quality of Service (QoS) demands, this dissertation proposes a frame-based DBA scheme to satisfy the QoS requirements of each traffic type of triple-play services. Meanwhile, based on M/G/1 queueing model, this study develops an analytical model for evaluating multiuser cyclic polling system to derive the closed-form expressions for the network performance metric such as mean packet delay. A series of comparisons between the numerical and analytical results are performed to show the validity of the proposed frame-based DBA scheme.
The third part is to discuss the issue of the integration of EPON and the Broadband Wireless Access Networks (BWANs). Since the complementary features of these two network systems provide high bandwidth and mobility together with a low deployment cost, the problem of achieving an effective bandwidth division among the EPON and wireless traffic remains unresolved. The dissertation proposes an effective-bandwidth-division DBA scheme to accommodate the bandwidth sharing between the EPON and BWAN. Also, this study develops an N-user queueing model based on M/G/1 queueing model to evaluate the efficiency and the effectiveness of the proposed DBA scheme.
The fourth part of this dissertation is to discuss the effect of the increased propagation delay in LR-EPONs. It has no doubt that the increased propagation delay has led increased idle time for interleaved-based DBA schemes resulting in poor bandwidth utilization. Thus, the dissertation proposes a DBA scheme based on a decentralized manner over a WDM LR-EPON. In this scheduling scheme, the current study uses an Array Waveguide Grating (AWG) module to enable decentralized scheduling among all ONUs such that the network utilization is not degraded by the increased propagation delay. Finally, computer simulations are performed to compare with existing DBA schemes to verify the effectiveness and efficiency of the proposed DBA scheme.
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