Redes ópticas elásticas: un nuevo paradigma en las futuras redes de telecomunicaciones

Resumen

 

El tráfico en las redes de datos por fibra óptica ha tenido un crecimiento exponencial debido a la creciente demanda de información por parte de los usuarios finales, llevando a una saturación en la capacidad de las redes actuales. Proyectando los sistemas de transmisiones ópticos a tasas superiores a los 400 Gbps para redes de largo alcance, no será posible mantener la tecnología WDM de rejilla espectral fija de 50 GHz, la cual permite transmitir en la actualidad tasas hasta los 100 Gbps. Teniendo como limitación además del ancho espectral que ocuparía la información, la conmutación de los dispositivos para trabajar a altas frecuencias. En este contexto, surge el concepto de las redes ópticas elásticas, donde se emplea una rejilla de espectro flexible (flexi-grid) o sin rejilla (grid-less), con ancho espectral variable por canal según la demanda de ancho de banda, permitiendo una separación espectral flexible entre canales con el propósito de optimizar la eficiencia en el uso del espectro. Este artículo hace una revisión de los nuevos conceptos tecnológicos que conllevan el escenario de redes elásticas, y los posibles retos y limitaciones para el desarrollo de estas tecnologías. Recientes pruebas experimentales incorporan nuevos conceptos tecnológicos con relación a los ya comerciales sistemas de 100-G como: el diseño de transmisores multicanales, el uso de tecnologías como Nyquist-WDM y OFDM óptico flexible, receptores digitales coherentes reconfigurables, formatos de modulación m-arios e híbridos y asignación dinámica del espectro. No obstante, grandes limitantes como los efectos no lineales de la fibra óptica deben ser foco de investigación en este nuevo escenario, debido a sus efectos en la degradación de la señal. Finalmente, se muestra como las técnicas de procesamiento digital de señales desempeñarán un papel importante para lograr la reconfigurabilidad y elasticidad de las redes de alta capacidad.

Palabras clave: Comunicaciones por Fibra Óptica, Enrutamiento, Interferencia Intercanal (ICI), Multiplexación por División de Longitud de Onda, Óptica No-Lineal, Procesamiento Digital de Señales (DSP), Redes Ópticas.

 

Abstract


In the last years, traffic on data optical networks has had an exponential growth due to the increasing demand of information by end users. This had lead to saturation of the current deployed networks in terms of capacity. Planning the optical transmission systems of long-reach to work with capacities above 400 Gbps, it will not be possible to keep the spectral fixed-grid of the WDM technology, which currently allows transmitting up to 100 Gbps. The principal limitation is due to the greater spectral bandwidth occupied by the data information and also due to the switching of electronics devices at high frequencies. In this context a new concept known as elastic optical network emerges, which proposes a flexible-grid or gridless, where the spectral width changes according to the bandwidth demand and allows optimizing the spectral efficiency with a minimum separation between adjacent channels. In this paper, we present a comprehensive survey of elastic optical networks, introducing new concepts and describing the challenges and the limitations in these networks. Recent experimental reports show new technological concepts related to the commercials 100-G systems such as: design of multichannels transmitters, gridless Nyquist-WDM and Optical-OFDM, reconfigurable digital coherent receivers, optical dynamic spectrum allocation and advanced modulation formats. Nevertheless, the nonlinearity effects of the optical fiber are a significant limitation that must be researched in detail in this new elastic scenario. Hence, it is shown how the digital signal processing techniques are going to play an important role in order to get high capacity in elastic and reconfigurable networks.

Keywords: Optical Fiber Communications, Routing, Interchannel Interference (ICI), Wavelength Division Multiplexing (WDM), Nonlinear Optics, Digital Signal Processing (DSP), All-Optical Networks.

 

Resumo

 

O trafego nas redes de dados por fibra óptica tem tido um crescimento exponencial devido à crescente demanda de informação por parte dos usuários finais, levando a uma saturação na capacidade das redes atuais. Projetando os sistemas de transmissões ópticos a taxas superiores aos 400 Gbps para redes de longo alcance, não será possível manter a tecnologia WDM de grelha fixa espectral de 50 GHz, a qual permite transmitir na atualidade taxas até os 100 Gbps. Tendo como limitação ademais da largura espectral que ocuparia a informação, a comutação dos dispositivos para trabalhar a altas frequências. Neste contexto, surge o conceito das redes ópticas elásticas, onde se emprega uma grelha de espectro flexível (flexi-grid) ou sem grelha (grid-less), com largura espectral variável por canal segundo a demanda da largura de banda, permitindo uma separação espectral flexível entre canais com o propósito de otimizar a eficiência no uso do espectro. Este artigo faz uma revisão dos novos conceitos tecnológicos que envolvam o cenário de redes elásticas, e os possíveis desafios e limitações para o desenvolvimento destas tecnologias. Recentes provas experimentais incorporam novos conceitos tecnológicos com relação aos já comerciais sistemas de 100-G como: o design de transmissores multicanais, o uso de tecnologias como Nyquist-WDM e OFDM óptico flexível, receptores digitais coerentes reconfiguráveis, formatos de modulação M-ária e híbridos, e assinação dinâmica do espectro. Não obstante, grandes limitantes como os efeitos não lineares da fibra óptica devem ser foco de pesquisa neste novo cenário, devido a sus efeitos na degradação do sinal. Finalmente, mostra-se como as técnicas de processamento de sinal digital irá desempenhar um papel importante na realização do restabelecemento e flexibilidade de redes de alta capacidade.

Palavras-chave: Comunicações por Fibra Óptica, Interferência Entre Canais (IEC), Multiplexação por Divisão de Longitude de Onda, Óptica Não-Lineal, Processamento Digital de Sinais (PDS), Redes Ópticas, Routing.

 

Biografía del autor/a

Jhon James Granada-Torres, Universidad de Antioquia

Magíster en Ingeniería de Telecomunicaciones

Estudiante de Doctorado en Ingeniería Electrónica de la Universidad de Antioquia

Ana María Cárdenas-Soto, Universidad de Antioquia

PhD en Telecomunicaciones.

Profesora asociada en la Universidad de Antioquia

Neil Guerrero-González, Tyndall National Institute Cork

PhD en Fotónica

Investigador Posdoctoral en Tyndall National Institute

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Cómo citar
Granada-Torres, J. J., Cárdenas-Soto, A. M., & Guerrero-González, N. (2015). Redes ópticas elásticas: un nuevo paradigma en las futuras redes de telecomunicaciones. Respuestas, 20(2), 6-22. https://doi.org/10.22463/0122820X.350

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Publicado
2015-07-01
Sección
Artículos