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.read more
Citations
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Proceedings ArticleDOI
A survey of recent developments on flexible/elastic optical networking
TL;DR: In this article, a review of the recent developments on the research topic of flexible/elastic networking and highlight the future research challenges is presented, with a focus on the future challenges.
Journal ArticleDOI
Nyquist-WDM-Based Flexible Optical Networks: Exploring Physical Layer Design Parameters
Eleni Palkopoulou,G. Bosco,Andrea Carena,Dimitrios Klonidis,Pierluigi Poggiolini,Ioannis Tomkos +5 more
TL;DR: In this paper, the impact of introducing flexibility in physical layer design parameters on the network level performance was examined in a Nyquist-WDM-based flexible optical networks and the authors showed that significant savings can be achieved by allowing the symbol rate to be dynamically tuned under different launch power options.
Journal ArticleDOI
A spectrum allocation scheme based on first-last-exact fit policy for elastic optical networks
TL;DR: Simulation results show that the proposed scheme outperforms the conventional scheme in terms of blocking probability, and the exact fit policy provides a higher number of contiguous available slots.
Proceedings ArticleDOI
Off-line algorithms for Routing, Modulation Level, and Spectrum Assignment in elastic optical networks
TL;DR: This paper forms RMLSA as an Integer Linear Programming (ILP) problem and proposes an effective heuristic method called Adaptive Frequency Assignment - Division and Collision Avoidance (AFA-DCA) to be used if the solution of ILP is not attainable.
Journal ArticleDOI
Energy Challenges in Current and Future Optical Transmission Networks
TL;DR: How energy constraints might shape future optical communication networks and the impact that current technology trends may have on future energy use are examined.
References
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