257 research outputs found

    A survey on OFDM-based elastic core optical networking

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    Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed

    Software Defined Applications in Cellular and Optical Networks

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    abstract: Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

    Impact of Fiber Duplication on Protection Architectures Feasibility for Passive Optical Networks

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    Adaptability of high capacity passive optical network (PON) requires the provision of an efficient fault detection and restoration mechanism throughout the network at an acceptable cost. The readily adapted pre-planned protection strategy relies on component duplication, which significantly increases the cost of deployment for PON. Therefore, it is imperative to determine a suitable component that requires high redundancy and determine the impact of protection for that component on feasibility of PON. Five protection architecture including ITU-T 983.1 Type C, single ring, dual ring, tree- and ring-based architectures with hybrid star-ring topology at the optical distribution network (ODN), are considered to evaluate the impact of fiber duplication in terms of capital expenditure (CAPEX), operation expenditure (OPEX), reliability, and support for maximum number of subscribers. Reliability block diagram (RBD) based analysis shows that desirable 5 nines connection availability is provided by each protection architecture and utilization of ring topology avoids duplication of the fiber but effects the number of subscribers. Furthermore, it is observed that OF duplication at ODN is the main contributor to CAPEX. Collectively hybrid protection architectures provide efficient performance and proves to be a feasible solution for the deployment of survivable PONs at the access domain

    Architecture and algorithm for reliable 5G network design

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    This Ph.D. thesis investigates the resilient and cost-efficient design of both C-RAN and Xhaul architectures. Minimization of network resources as well as reuse of already deployed infrastructure, either based on fiber, wavelength, bandwidth or Processing Units (PU), is investigated and shown to be effective to reduce the overall cost. Moreover, the design of a survivable network against a single node (Baseband Unit hotel (BBU), Centralized/Distributed Unit (CU/DU) or link failure proposed. The novel function location algorithm, which adopts dynamic function chaining in relation to the evolution of the traffic estimation also proposed and showed remarkable improvement in terms of bandwidth saving and multiplexing gain with respect to conventional C-RAN. Finally, the adoption of Ethernet-based fronthaul and the introduction of hybrid switches is pursued to further decrease network cost by increasing optical resource usage

    Enabling Technology in Optical Fiber Communications: From Device, System to Networking

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    This book explores the enabling technology in optical fiber communications. It focuses on the state-of-the-art advances from fundamental theories, devices, and subsystems to networking applications as well as future perspectives of optical fiber communications. The topics cover include integrated photonics, fiber optics, fiber and free-space optical communications, and optical networking

    Energy Efficient Survivable IP over WDM Networks with Network Coding

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    In this work we investigate the use of network coding in 1+1 survivable IP over WDM networks by encoding the protection paths of multiple flow with each other at intermediate nodes. We study the energy efficiency of this scheme through MILP, and a heuristic with five operating options. We evaluate the MILP and the heuristics on typical and regular network topologies. Our results show that implementing network coding can produce savings up to 37% on the ring topology and 23% considering typical topologies. We also study the impact of varying the demand volumes on the network coding performanc
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