Physical Layer Impairments Aware Dynamic Lightpath Provisioning In Mixed Line Rate Wdm Networks

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2014Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2014Bu tez çalışmasında, fiziksel katman bozukluklarını dikkate alarak, çoklu veri iletişim hızlı ağlarda dinamik olarak gelen bağlantı istekleri için ısıkyolu kurma problemi ele alınmıştır. Problemde verilenler; dinamik olarak gelen farklı kapasitelerde bağlantı istekleri, fiziksel topoloji, fiziksel hatların taşıyabildiği dalgaboyu miktarı, ağın anlık durumu ve fiziksel katman bozukluklarını dikkate alırken kullanılacak olan parametrelerdir. Problemde istenilen ise; gelen bağlantı isteklerinin mümkün olduğu kadar fazlasını kurabilmek maksadı ile uygun yol ve dalgaboyunun bulunmasıdır. Bunu gerçekleştirirken, hem kurulacak olan ışıkyolunun sinyal kalitesinin kabul edilebilir bit hata oranını karşılaması, hem de sistemde daha önceden kurulmuş olan ışıkyollarının sinyal kalitesinin kabul edilebilir sınırların altına inmesini engellemek gerekmektedir. Bu tez çalışmasında, kurulabilen ışıkyolu miktarını artırmak maksadı ile ışıkyolunun sisteme giriş gücü de ayrıca ele alınmıştır.In this thesis, we studied the impairment-aware lightpath provisioning problem for dynamic connection requests in MLR networks. Given, a dynamic connection request with a given rate, physical topology, number of wavelengths carried by each fiber, current network state, and PLI parameters, our aim is to determine the route and wavelength over which the lightpath should be set up, in order to be able to maximize the number of established connections while satisfying the given bit-error rate (BER) for the incoming connection, and to avoid disrupting the existing lightpaths. We also evaluate the launch power of the lightpath to maximize the established connections.DoktoraPh

WDM/TDM PON bidirectional networks single-fiber/wavelength RSOA-based ONUs layer 1/2 optimization

This Thesis proposes the design and the optimization of a hybrid WDM/TDM PON at the L1 (PHY) and L2 (MAC) layers, in terms of minimum deployment cost and enhanced performance for Greenfield NGPON. The particular case of RSOA-based ONUs and ODN using a single-fibre/single-wavelength is deeply analysed. In this WDM/TDM PON relevant parameters are optimized. Special attention has been given at the main noise impairment in this type of networks: the Rayleigh Backscattering effect, which cannot be prevented. To understand its behaviour and mitigate its effects, a novel mathematical model for the Rayleigh Backscattering in burst mode transmission is presented for the first time, and it has been used to optimize the WDM/TDM RSOA based PON. Also, a cost-effective, simple design SCM WDM/TDM PON with rSOA-based ONU, was optimized and implemented. This prototype was successfully tested showing high performance, robustness, versatility and reliability. So, the system is able to give coverage up to 1280 users at 2.5 Gb/s / 1.25 Gb/s downstream/upstream, over 20 Km, and being compatible with the GPON ITU-T recommendation. This precedent has enabled the SARDANA network to extend the design, architecture and capabilities of a WDM/TDM PON for a long reach metro-access network (100 km). A proposal for an agile Transmission Convergence sub-layer is presented as another relevant contribution of this work. It is based on the optimization of the standards GPON and XG-PON (for compatibility), but applied to a long reach metro-access TDM/WDM PON rSOA-based network with higher client count. Finally, a proposal of physical implementation for the SARDANA layer 2 and possible configurations for SARDANA internetworking, with the metro network and core transport network, are presented

Optical Switching for Scalable Data Centre Networks

This thesis explores the use of wavelength tuneable transmitters and control systems within the context of scalable, optically switched data centre networks. Modern data centres require innovative networking solutions to meet their growing power, bandwidth, and scalability requirements. Wavelength routed optical burst switching (WROBS) can meet these demands by applying agile wavelength tuneable transmitters at the edge of a passive network fabric. Through experimental investigation of an example WROBS network, the transmitter is shown to determine system performance, and must support ultra-fast switching as well as power efficient transmission. This thesis describes an intelligent optical transmitter capable of wideband sub-nanosecond wavelength switching and low-loss modulation. A regression optimiser is introduced that applies frequency-domain feedback to automatically enable fast tuneable laser reconfiguration. Through simulation and experiment, the optimised laser is shown to support 122×50 GHz channels, switching in less than 10 ns. The laser is deployed as a component within a new wavelength tuneable source (WTS) composed of two time-interleaved tuneable lasers and two semiconductor optical amplifiers. Switching over 6.05 THz is demonstrated, with stable switch times of 547 ps, a record result. The WTS scales well in terms of chip-space and bandwidth, constituting the first demonstration of scalable, sub-nanosecond optical switching. The power efficiency of the intelligent optical transmitter is further improved by introduction of a novel low-loss split-carrier modulator. The design is evaluated using 112 Gb/s/λ intensity modulated, direct-detection signals and a single-ended photodiode receiver. The split-carrier transmitter is shown to achieve hard decision forward error correction ready performance after 2 km of transmission using a laser output power of just 0 dBm; a 5.2 dB improvement over the conventional transmitter. The results achieved in the course of this research allow for ultra-fast, wideband, intelligent optical transmitters that can be applied in the design of all-optical data centres for power efficient, scalable networking

Telecommunication Systems

This book is based on both industrial and academic research efforts in which a number of recent advancements and rare insights into telecommunication systems are well presented. The volume is organized into four parts: "Telecommunication Protocol, Optimization, and Security Frameworks", "Next-Generation Optical Access Technologies", "Convergence of Wireless-Optical Networks" and "Advanced Relay and Antenna Systems for Smart Networks." Chapters within these parts are self-contained and cross-referenced to facilitate further study

Static resource allocation for dynamic traffic

A flexible offline probabilistic (FOP) algorithm is designed to aggressively accommodate random bandwidth traffic demands in long-haul networks. Compared to algorithms that configure demands according to their maximum bandwidth, the FOP algorithm can save 15% of the spectrum used, accommodating over 99% of the throughput demand

Journal of Telecommunications and Information Technology, 2009, nr 1

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