http://hdl.handle.net/2117/2038 2013-05-20T06:02:22Z http://hdl.handle.net/2117/19350 Title: ONU optimal gain and position of the distribution element in Rayleigh-limited WDM and TDM PONs with reflective ONU Authors: López Pastor, Eduardo Tommy; Lázaro Villa, José Antonio; Arellano Pinilla, Cristina; Polo Querol, Víctor; Prat Gomà, Josep Joan Abstract: The influence of the distribution element position in PONs is reported. Best Crosstalk-to-Signal ratio (C/S) is achieved if it is placed either in the ONU or OLT vicinity with optimum ONU gain depending of the MUX position 2013-05-17T14:55:56Z http://hdl.handle.net/2117/19277 Title: Planning and designing FTTH networks: elements, tools and practical issues Authors: Segarra Mullerat, Josep; Sales Zaragoza, Vicente; Prat Gomà, Josep Joan Abstract: Fiber-To-The Home (FTTH) provides the offered and new broadband services. Now it is deployed massively worldwide with Passive Optical Networks (PONs), being the EPON and GPON standards the most used. In this paper we consider solutions for planning and designing such optical fiber access networks from the point of view of an incumbent operator; taking into account components administration, mapping tools, design applications and automation resources; therefore, managing infrastructures, materials, geography, houses,buildings and users databases. The networks will be dynamic, so the proposed designs and utilities must also be active to reach thousands of passed homes and to cover the life-cycle of the networks and not only the initial built. 2013-05-16T09:18:55Z http://hdl.handle.net/2117/19269 Title: Optical filter cascading effects in a phase modulated coherent optical OFDM transmission system based on Hartley transform Authors: Chochol, M.; Fabrega, J.M.; Svaluto Moreolo, Michela; Junyent Giralt, Gabriel Abstract: Effects of cascading optical filters are investigated for a phase modulated coherent optical OFDM system based on Hartley transform. The evaluation is performed by means of numeric simulations in a 10 Gb/s system with a total bandwidth of 10 GHz. First a back-to-back (no fiber) case is assessed. Results show a 3 dB power penalty after a single filter of only 68% of the signal bandwidth. The same penalty is achieved when cascading 10 filters of 21.6 GHz bandwidth. Additionally, the penalties associated to the introduction of fiber spans between filters are investigated. 2013-05-15T16:39:16Z http://hdl.handle.net/2117/19250 Title: Path-based recovery in flexgrid optical networks Authors: Castro Casales, Alberto; Ruiz Ramírez, Marc; Velasco Esteban, Luis Domingo; Junyent Giralt, Gabriel; Comellas Colomé, Jaume Abstract: With the advent of flexgrid optical networks, the rigid wavelength-division multiplexing (WDM) technology will be enhanced by providing better spectrum efficiency and flexibility. In those future flexible optical networks, optical connections (lightpaths) can allocate a flexible number of spectrum slices, also known as frequency slots, so to match better with its requested bitrate. In this paper, we propose to take advantage of this flexible spectrum allocation in recovery mechanisms to be triggered when a failure occurs to provide recovery of part of the requested bitrate, i.e. the allocated spectrum by backup lightpaths could be lower than that of the working lightpaths provided that client service level agreements are fulfilled. This reduction in the recovered bitrate (bitrate squeezing) allows optimizing the use of network capacity. We propose path-based recovery alternatives, based on protection and restoration, specially designed for flexgrid networks. The performance of the proposed recovery mechanisms is exhaustively evaluated on a national reference network 2013-05-15T13:22:36Z http://hdl.handle.net/2117/19056 Title: Power efficiency of SARDANA and other long-reach optical acces networks Authors: Lovric, Ana; Aleksic, Slavisa; Lázaro Villa, José Antonio; Tosi Beleffi, Giorgio; Prat Gomà, Josep Joan; Polo Querol, Víctor Abstract: Different long-reach optical access networks are studied with respect to their power efficiency. Special focus is dedicated to the hybrid TDM/WDM PON proposed in the SARDANA project, in which remote amplification is utilized for reach extension. The structures of the remote nodes and subsystems for reach extension are shown and discussed. The influence of uplink capacity limitation on power efficiency is evaluated, i.e., the access networks' efficiencies are presented for different CO capacities in terms of Watt per user and per Gbit/s of user's bandwidth as a function of number of users connected to the CO. The results show remarkable power efficiency degradation for high-speed access technologies in case of strong uplink limitation, while for unlimited uplink case, 10G-EPON and SARDANA networks show the best efficiency. Description: Best Paper of ONDM'2011 2013-04-30T11:55:24Z http://hdl.handle.net/2117/18978 Title: Modeling the routing and spectrum allocation problem for flexgrid optical networks Authors: Velasco Esteban, Luis Domingo; Klinkowski, Miroslaw; Ruiz Ramírez, Marc; Comellas Colomé, Jaume Abstract: Flexgrid optical networks are attracting huge interest due to their higher spectrum efficiency and flexibility in comparison with traditional wavelength switched optical networks based on the wavelength division multiplexing technology. To properly analyze, design, plan, and operate flexible and elastic networks, efficient methods are required for the routing and spectrum allocation (RSA) problem. Specifically, the allocated spectral resources must be, in absence of spectrum converters, the same along the links in the route (the continuity constraint) and contiguous in the spectrum (the contiguity constraint). In light of the fact that the contiguity constraint adds huge complexity to the RSA problem,we introduce the concept of channels for the representation of contiguous spectral resources. In this paper, we show that the use of a pre-computed set of channels allows considerably reducing the problem complexity. In our study, we address an off-line RSA problem in which enough spectrum needs to be allocated for each demand of a given traffic matrix. To this end, we present novel integer lineal programming (ILP) formulations of RSA that are based on the assignment of channels. The evaluation results reveal that the proposed approach allows solving the RSA problem much more efficiently than previously proposed ILP-based methods and it can be applied even for realistic problem instances, contrary to previous ILP formulations. 2013-04-24T11:33:35Z http://hdl.handle.net/2117/18977 Title: Demonstration of GMPLS-controlled device power management for next generation green optical networks Authors: Morea, Annalisa; Perelló Muntan, Jordi; Agraz Bujan, Fernando; Spadaro, Salvatore Abstract: We propose GMPLS protocol enhancements enabling dynamic power state management of optoelectronic network devices for setup-time-aware differentiated connection provisioning. Daily energy savings of 56% are demonstrated in a Pan-European-like network compared to always on scenarios. 2013-04-24T10:52:07Z http://hdl.handle.net/2117/18499 Title: Low complexity bit rate variable transponders based on optical OFDM with PAPR reduction capabilities Authors: Nadal, Laia; Svaluto Moreolo, Michela; Fàbrega Sánchez, Josep Maria; Junyent Giralt, Gabriel Abstract: In this paper, we propose low complexity bit rate variable transponders for adaptive DC biased Optical OFDM systems. The transponders are based on an alternative transform, the fast Hartley transform (FHT), and use adaptively modulated O-OFDM (AMO-OFDM) to introduce flexibility to optical networks. Additionally, low complexity selective mapping (LC-SLM) technique is included in the bit rate variable transponders to mitigate the effects of the peak-to-average power ratio (PAPR)and reduce the clipping noise, enabling the use of low bias values. 2013-03-22T13:20:25Z http://hdl.handle.net/2117/18402 Title: Optical subsystems for next generation access networks Authors: Lázaro Villa, José Antonio; Polo Querol, Víctor; Schrenk, Bernhard; Bonada Bo, Francesc; Cano Valadéz, Iván Nicolás; López, E.T.; Kazmierski, Christophe; de Valicourt, Guilhem; Brenot, Romain; Bauwelinck, Johan; Xing-Zhi, Qiu; Ossieur, P.; Forzati, Marco; Rigole, Jean-Pierre; Monroy, I.T; Tangdiongga, E.; Morant, Maryland; Nicolau, L.; Teixeira, A.L.; Erasme, D.; Klonidis, Dimitrios; Tomkos, Ioannis; Prat Gomà, Josep Joan; Kouloumentas,, Christos; Avramopoulos, Hércules Abstract: Recent optical technologies are providing higher flexibility to next generation access networks: on the one hand, providing progressive FTTx and specifically FTTH deployment, progressively shortening the copper access network; on the other hand, also opening fixed-mobile convergence solutions in next generation PON architectures. It is provided an overview of the optical subsystems developed for the implementation of the proposed NG-Access Networks. 2013-03-19T13:18:55Z http://hdl.handle.net/2117/18273 Title: An OFDMA-PON with non-preselected independent ONU sources and centralized feedback wavelength control: Dimensioning and experimental results Authors: Cano Valadéz, Iván Nicolás; Santos Blanco, M. Concepción; Escayola Elias, Francisco Javier; Polo Querol, Víctor; Giacoumidis, E.; Kachris, C.; Tomkos, Ioannis; Prat Gomà, Josep Joan Abstract: A simple and low cost method for wavelength control based on centralized OLT monitoring and feedback of economical random non-preselected independent ONU sources is presented. The technique was dimensioned and experimentally tested in an OFDMA-PON with 1 Gb/s ONUs and 30 km of fibre along with the minimum optical spectral gap between consecutive ONU wavelengths. Results indicate that this method reduces the spectral overlap probability and increasing the number of users and cost-effectiveness of a PON, 2013-03-13T15:52:48Z http://hdl.handle.net/2117/18107 Title: Routing protocol enhancements for power state engineering of green network elements Authors: Verchere, Dominique; Morea, Annalisa; Spadaro, Salvatore; Le Sauze, Nicolas Abstract: A routing protocol is enhanced to advertise the power state of node interfaces for wavelength switched optical networks to allow tuning the power consumption according to the data traffic demands. By engineering the different power states, GMPLS controlled nodes are configured to preserve the QoS of incoming traffic volumes such as reliability as well as the constraints of carrier grade networks, such as stability and operation costs. For variable incoming traffic reference models, more than half of the total power consumption required for an European optical networks without any power saving capabilities can be saved from powering the optoelectronic interfaces column. 2013-03-06T14:56:43Z http://hdl.handle.net/2117/18103 Title: An Open source multiplatform virtual laboratory for engineering education : special focus paper Authors: Fernández Canti, Rosa M.; Lázaro Villa, José Antonio; Zarza Sánchez, Sergio; Villar Zafra, Aitor Abstract: An autonomous and multiplatform virtual laboratory for educational purposes is presented. The implemented platform includes a server with a SSH (Secure SHell) connection and a separated repository containing the virtual experiments. The programming of the experiments is implemented in Java language based tool, the EJS (Easy Java Simulation) and uses an external computation engine, for example Matlab. The virtual laboratory provides control system experiments at University level. Two application examples are described, namely, a magnetic levitator and an inverted pendulum-cart system. The virtual laboratory has been successfully used for education and training of Electronics Engineering students. A discussion of the results of this e-learning experience is also presented. 2013-03-06T13:41:53Z http://hdl.handle.net/2117/18019 Title: Network convergence and QoS for future multimedia services in the VISION project Authors: Pérez, Luís; Velasco Esteban, Luis Domingo; Rodríguez, Juan; Capelastegui, Pedro; Hernández Sola, Guillem; Calavia, Lorena; Marqués, Antonio; Iribarne, Borja; Pozo, Amador; Poorter, Antoine De Abstract: The emerging use of real-time 3D-based multimedia applications imposes strict quality of service (QoS) requirements on both access and core networks. These requirements and their impact to provide end-to-end 3D videoconferencing services have been studied within the Spanish-funded VISION project, where different scenarios were implemented showing an agile stereoscopic video call that might be offered to the general public in the near future. In view of the requirements, we designed an integrated access and core converged network architecture which provides the requested QoS to end-to-end IP sessions. Novel functional blocks are proposed to control core optical networks, the functionality of the standard ones is redefined, and the signaling improved to better meet the requirements of future multimedia services. An experimental test-bed to assess the feasibility of the solution was also deployed. In such test-bed, set-up and release of end-to-end sessions meeting specific QoS requirements are shown and the impact of QoS degradation in terms of the user perceived quality degradation is quantified. In addition, scalability results show that the proposed signaling architecture is able to cope with large number of requests introducing almost negligible delay. 2013-02-28T11:54:08Z http://hdl.handle.net/2117/17904 Title: Multiplatform virtual laboratory for engineering education Authors: Villar Zafra, Aitor; Zarza Sánchez, Sergio; Lázaro Villa, José Antonio; Fernández Canti, Rosa M. Abstract: An autonomous and multi platform virtual laboratory for educational purposes is presented. The implemented platform includes a server with a SSH(Secure SHeil)connection and a separated repository containing the virtual experiments. The programming of the experiments is implemented in Java language based tool, the EJS (Easy Java Simulation) and uses an external computation engine, for example MatIab. The virtual laboratory provides control system experimentsat University level. Two application examples are described, namely, a magnetic levitator and an inverted pendulum­ cart system. The virtual laboratory has been successfully used for education and training of Electronics Engineering students. A discussion of the results of this e-learning experience is also presented. 2013-02-21T10:24:01Z http://hdl.handle.net/2117/17058 Title: WDM overlay of distributed base stations in deployed passive optical networks using coherent optical OFDM transceivers Authors: Fabrega, J.M.; Svaluto Moreolo, Michela; Chochol, M.; Junyent Giralt, Gabriel Abstract: It is proposed to reuse the deployed PON infrastructure by overlaying distributed radio base stations by means of very dense WDM with narrow channel spacings. In order to cope with that while minimizing its impact onto the performance of legacy equipment, coherent optical OFDM technology is used. Furthermore, the case of a practical implementation using CPRI is analyzed by means of simulations for several use cases. Within the analyzed use cases, a rural PON with 50 km reach has proven to support splitting ratios of up to 32 users, whereas an urban radio access network has been demonstrated to support ratios of up to 256 users within a radius of 2 km. 2012-12-03T10:43:38Z