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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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On the Impact of Optimal Modulation and FEC Overhead on Future Optical Networks

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Applying p-Cycle technique to elastic optical networks

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Software defined flexible and efficient passive optical networks for intra-datacenter communications

TL;DR: A seamless DBA (S-DBA) scheme and an ONU grouping algorithm are proposed to fully utilize the upstream idle time and minimize the traffic entering into the core layer of the datacenter networks.
Journal ArticleDOI

Spectrum efficient distance-adaptive paths for fixed and fixed-alternate routing in elastic optical networks

TL;DR: A new routing scheme for EON is proposed, namely, k -distance adaptive paths (KDAP) that efficiently utilizes the benefit of distance-adaptive modulation, and bit rate- Adaptive superchannel capability inherited by EON to improve spectrum utilization.
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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