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Journal ArticleDOI

Elastic Bandwidth Allocation in Flexible OFDM-Based Optical Networks

TLDR
This work introduces the Routing, Modulation Level and Spectrum Allocation (RMLSA) problem, as opposed to the typical Routing and Wavelength Assignment (RWA) problem of traditional WDM networks, proves that it is also NP-complete and presents various algorithms to solve it.
Abstract
Orthogonal Frequency Division Multiplexing (OFDM) has recently been proposed as a modulation technique for optical networks, because of its good spectral efficiency, flexibility, and tolerance to impairments. We consider the planning problem of an OFDM optical network, where we are given a traffic matrix that includes the requested transmission rates of the connections to be served. Connections are provisioned for their requested rate by elastically allocating spectrum using a variable number of OFDM subcarriers and choosing an appropriate modulation level, taking into account the transmission distance. We introduce the Routing, Modulation Level and Spectrum Allocation (RMLSA) problem, as opposed to the typical Routing and Wavelength Assignment (RWA) problem of traditional WDM networks, prove that is also NP-complete and present various algorithms to solve it. We start by presenting an optimal ILP RMLSA algorithm that minimizes the spectrum used to serve the traffic matrix, and also present a decomposition method that breaks RMLSA into its two substituent subproblems, namely 1) routing and modulation level and 2) spectrum allocation (RML+SA), and solves them sequentially. We also propose a heuristic algorithm that serves connections one-by-one and use it to solve the planning problem by sequentially serving all the connections in the traffic matrix. In the sequential algorithm, we investigate two policies for defining the order in which connections are considered. We also use a simulated annealing meta-heuristic to obtain even better orderings. We examine the performance of the proposed algorithms through simulation experiments and evaluate the spectrum utilization benefits that can be obtained by utilizing OFDM elastic bandwidth allocation, when compared to a traditional WDM network.

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Citations
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Proceedings ArticleDOI

Regenerator placement algorithms for cloud-ready Elastic Optical Networks

TL;DR: Results of experiments show that the cloud-aware location of regenerators can significantly reduce the blocking probability as well as reduce the number of used regenerators comparing to classical approaches.
Journal ArticleDOI

A Comparative Evaluation of Nature Inspired Algorithms for Telecommunication Network Design

TL;DR: The evolutionary algorithm, the bees algorithm and the harmony search algorithm showed superior performance for the considered data-sets corresponding to large optical networks; the integer programming-based algorithm failed to find an acceptable sub-optimal solution within the assumed maximum computational time.
Journal ArticleDOI

Assessment of novel regenerator assignment strategies in dynamic translucent elastic optical networks

TL;DR: Two heuristics are presented and shown to provide solutions that provide very similar performance to those found by utilizing the best solutions of the exhaustive method to solve the RA problem in translucent elastic optical networks under dynamic traffic.
Proceedings ArticleDOI

Best fit (BF): A new Spectrum Allocation mechanism in Elastic Optical Networks (EONs)

TL;DR: Numerical results confirm the fact that the proposed BF outperforms the conventional mechanisms in terms of blocking probability, and it is verified that the Opt BF successfully alleviates the blocking probability even more, and assigns the networks resources efficiently.
Journal ArticleDOI

Strategies and benefits of deploying ultralow-loss fiber links in an elastic optical network

TL;DR: This work addresses the problem of superchannels using efficient formats for modulation in the context of an elastic optical network and proposes approaches for doing this for both static and dynamic traffic demands, and formulate the problem using mixed-integer linear-programing models and also propose efficient heuristic algorithms.
References
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Journal ArticleDOI

Combinatorial optimization: algorithms and complexity

TL;DR: This clearly written, mathematically rigorous text includes a novel algorithmic exposition of the simplex method and also discusses the Soviet ellipsoid algorithm for linear programming; efficient algorithms for network flow, matching, spanning trees, and matroids; the theory of NP-complete problems; approximation algorithms, local search heuristics for NPcomplete problems, more.
Journal ArticleDOI

OFDM for Optical Communications

TL;DR: In this paper, the authors give a tutorial overview of OFDM and highlight the aspects that are likely to be important in optical applications, and discuss the constraints imposed by single mode optical fiber, multimode optical fiber and optical wireless.
Journal ArticleDOI

Spectrum-efficient and scalable elastic optical path network: architecture, benefits, and enabling technologies

TL;DR: This article proposes a novel, spectrum- efficient, and scalable optical transport network architecture called SLICE, which enables sub-wavelength, superwa wavelength, and multiple-rate data traffic accommodation in a highly spectrum-efficient manner, thereby providing a fractional bandwidth service.
Journal ArticleDOI

Distance-adaptive spectrum resource allocation in spectrum-sliced elastic optical path network [Topics in Optical Communications]

TL;DR: A concept of a novel adaptation scheme in SLICE called distance-adaptive spectrum resource allocation, which can save more than 45 percent of required spectrum resources for a 12-node ring network, is presented.
Journal ArticleDOI

Optical burst switching: a new area in optical networking research

TL;DR: This tutorial gives an introduction to optical burst switching and compare it with other existing optical switching paradigms, and describes a prevailing protocol for OBS networks called just-enough-time (JET).
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