Self-adjusting DBA algorithm for next generation PONs (NG-PONs) to support 5G fronthaul and data services

In this article, we propose a novel dynamic bandwidth allocation (DBA) algorithm for NG-PON networks to jointly support 5G fronthaul and best effort data services in the same PON channel. The proposed self-adjusting DBA adjusts dynamically the allocation intervals to the current required fronthaul throughput based on the requests reported from the ONUs. It is suitable for dynamic 5G scenarios where, for energy efficiency reasons, the fronthaul connections are dynamically set up and torn down over time: when a new 5G fronthaul connection is set up, the maximum latency of the current connections is guaranteed while when a current 5G fronthaul connection is torn down, the freed transmission resources become available for data services. The only requirement is that the capacity of the channel in the NG-PON network is enough for the throughput of all 5G fronthaul connections supported by the channel. In this way, the proposed self-adjusting DBA algorithm has the advantage of requiring a much lower management coordination between the 5G infrastructure and the NG-PON infrastructure than the one required when the throughput of the 5G fronthaul connections is supported as a guaranteed service.publishe

Demonstration of a partially integrated silicon photonics ONU in a self-coherent reflective FDMA PON

We report about the final results of the FABULOUS European project, demonstrating the feasibility of real-time Ethernet transmission on a self-coherent reflective passive optical network, using an optical network unit (ONU) whose main optical functions are performed by a silicon-photonics device; 500 Mbps per user with a power budget of 24 dB in offline processing and 21 dB in real time is shown. We also report details about the packaging process and the special technique developed for the flip-chipping of a CMOS electrical driver, used for driving the ONU with low voltage, onto a silicon Mach-Zehnder modulator

Sistemas de calibração automático para transceivers NG-PON2

The current society is increasingly dependent on communication services, requiring better and faster connections, predicting in a near future connections in the order of hundreds of Gbit/s. During the data transmissions, the increase of speed reflects an increase of the error ratio due to factors such as noise, reductions of signal or jitter, which for low speed these were not emphasized so much. This project involves the development of a BER test system for both continuous and Burst mode of the transmission, demonstrating the viability of communication over the next-generation technology, NG-PON2, which uses high transmission rates (10 Gbit/s). For this purpose, an FPGA architecture was implemented that allows for long distances in the optical network, high transmission rates. This choice reflects a more economical alternative in relation to commercial equipment and has several advantages, such as the flexibility to reprogram and prepare the architecture according to the needs of the user. To achieve the proposed requirements, the project was divided into three parts. In the first part an architecture was developed that allows to obtain the error rate during a continuous mode transmission. In order to obtain the real-time viability of the communication referred and to have control over the system, an interface was developed between the computer and the FPGA to change certain characteristics of the communication channel. This is the second part of the project. The last part of the project has an architecture similar to the previous one, that is, instead of the transmission to be done in continuous mode, it is performed in mode Burst, being this the requirement with more interest to the technology NG-PON2. Finally, proof of concept was performed through an optical network provided by the company PICadvanced that allowed the validation of the different parts of the project. These validations will allow the development of new modules that will later contribute to the main project that is under development in the company PICadvanced, which aims at the construction of an automatic calibration board for the XFP transceivers.A sociedade atual depende cada vez mais dos serviços de comunicação, exigindo melhores ligações e mais rápidas, prevendo-se num futuro próximo a necessidade de ligações na ordem das centenas de Gbit/s. O aumento dos ritmos de transmissão refletem um aumento no que se refere à taxa de erro (BER), uma vez que o impacto associado a fatores como ruı́do ou interferência entre sı́mbolos, é maior do que para baixos ritmos. Este trabalho foca-se no desenvolvimento de um sistema de teste BER, tanto para uma transmissão contı́nua como para transmissão em rajadas, que demonstre a viabilidade da comunicação sobre a tecnologia da próxima geração, Next Generation Passive Optical Network 2 (NG-PON2), que utiliza débitos de transmissão elevados (10 Gbit/s). Para este efeito foi implementado uma arquitetura em Field-programmable gate array (FPGA) que possibilita para longas distâncias na rede ótica, elevados ritmos de transmissão. Esta escolha reflete uma alterativa mais económica em relação aos equipamentos comerciais e apresenta vantagens tais como a flexibilidade de reprogramar e preparar a arquitetura de acordo com as necessidades do utilizador. Para cumprir os requisitos propostos o projeto dividiu-se em três partes. Numa primeira parte do projeto desenvolveu-se uma arquitetura que permite adquirir a taxa de erros durante uma transmissão contı́nua. Com o intuito de analisar a viabilidade em tempo real da comunicação em questão, bem com o utilizador ter controlo sobre o sistema, alterando certas caracterı́sticas do canal de comunicação, desenvolveu-se numa segunda parte do projeto uma interface entre o computador e a FPGA. Numa última parte do projeto desenvolveu-se uma arquitetura semelhante à anterior, na qual se permite igualmente adquirir a taxa de erros com transmissão em rajadas (Burst), sendo este um dos requisitos de maior interesse na tecnologia NG-PON2. Por fim, a prova de conceito foi realizada através de uma rede ótica disponibilizada pela empresa PICadvanced, que permitiu a validação das diversas partes do projeto. Estas validações vão permitir a conceção de novos módulos que posteriormente vão contribuir para o projeto fonte que está em desenvolvimento na empresa PICadvanced, que visa a implementação de uma placa de calibração automatizada para os transceptores 10 Gigabit Small Form Factor Pluggables (XFP).Mestrado em Engenharia Eletrónica e Telecomunicaçõe

Wavelength reconfigurability for next generation optical access networks

Next generation optical access networks should not only increase the capacity but also be able to redistribute the capacity on the fly in order to manage larger variations in traffic patterns. Wavelength reconfigurability is the instrument to enable such capability of network-wide bandwidth redistribution since it allows dynamic sharing of both wavelengths and timeslots in WDM-TDM optical access networks. However, reconfigurability typically requires tunable lasers and tunable filters at the user side, resulting in cost-prohibitive optical network units (ONU). In this dissertation, I propose a novel concept named cyclic-linked flexibility to address the cost-prohibitive problem. By using the cyclic-linked flexibility, the ONU needs to switch only within a subset of two pre-planned wavelengths, however, the cyclic-linked structure of wavelengths allows free bandwidth to be shifted to any wavelength by a rearrangement process. Rearrangement algorithm are developed to demonstrate that the cyclic-linked flexibility performs close to the fully flexible network in terms of blocking probability, packet delay, and packet loss. Furthermore, the evaluation shows that the rearrangement process has a minimum impact to in-service ONUs. To realize the cyclic-linked flexibility, a family of four physical architectures is proposed. PRO-Access architecture is suitable for new deployments and disruptive upgrades in which the network reach is not longer than 20 km. WCL-Access architecture is suitable for metro-access merger with the reach up to 100 km. PSB-Access architecture is suitable to implement directly on power-splitter-based PON deployments, which allows coexistence with current technologies. The cyclically-linked protection architecture can be used with current and future PON standards when network protection is required

Dynamic Bandwidth Allocation for NG-PONs with channel bonding

Channel bonding is a recently proposed technique to provide higher aggregated line rates in NG-PONs by allowing ONUs to operate simultaneously in multiple wavelengths. On the other hand, the Dynamic Bandwidth Allocation (DBA) algorithm allocates to each ONU the grant time interval on each upstream frame that the ONU can use to transmit its data in the upstream direction. Channel bonding imposes a new challenge in the DBA algorithm as the grant time interval allocated to a ONU must be the same in all its channel-bonded wavelengths. In this work, we propose a new DBA algorithm for NG-PONs supporting data services which is a combination of a proportional fairness strategy and a max-min fairness strategy and guarantees the constraints imposed by channel bonding. We illustrate the merits of the new algorithm with two cases based on simulation. The results show that channel bonding can provide better QoS performance to data services even in cases where it is not strictly required.publishe

Circuitos óticos integrados para PONs de futura geração

Mestrado em Engenharia Eletrónica e TelecomunicaçãoWe are living in a time where communications became essential for most of our lives, whether it's in the business world, or in our own homes. The increasing need of higher bandwidth inhibits other networks other than optical ber based ones. Nowadays communications are responsible for a substantial percentage of our energetic footprint, hence Passive Optical Network(PON) are a strong contender for the next step of network implementation. These networks present a low energy consumption because between the transmitter and the receiver the signal stays in the optical domain. Although the increasing needs of bandwidth is almost across the communication world, certain services/identities need more bandwidth whether is download or upload. It's easy to understand that di erent consumers have unique needs. It's necessary to develop an architecture that serves all the costumers, in other words, there is a need for a network that provides high bitrate tra c to the users that needs it but also a network that serves the low end user that is not interested in this increase of bandwidth and therefore price in ation. There is today technologies yet to be widely implemented like NG-PON2 that were not implemented in a large scale because they dont represent a nancial return to the telecom operators simply because there is not enough user that requires the high bandwidth delivered by NG-PON2. It's necessary to nd a solution that includes not only the modern technologies but also the already implemented ones. With the objective of nding a solution for the problems mentioned before, this dissertation has the objective of designing a Photonic Integrated Circuit(PIC) that aims to be a transceiver of a Multitech Network that will be composed by the following technologies: Video-Overlay, XG-PON e NG-PON2. This dissertation presents an approach on Passive Optical Networks( PON) and the standards of the said technologies as well as a study of the components needed to assemble the transceiver using the programs ASPIC and VPI Photonics . In the end, there will be presented an architecture for the transceiver to be used in a Optical Network Unit(ONU), and the respective mask Layout.Vivemos numa época em que as comunicações se tornaram essenciais para grande parte da nossa vida, seja no mundo empresarial, seja nas nossas habitações. A crescente necessidade de aumento de largura de banda inviabiliza outras redes que não baseadas em braotica. Actualmente as comunicações são responsáveis por uma percentagem substancial dos nossos gastos energéticos, justamente por este facto Passive Optical Networks(PON) sao as principais candidatas ao próximo passo no desenvolvimento de redes. Estas apresentam menor consumo energético, pois entre o emissor e o receptor todo o sinal permanece no domínio óptico. Apesar da necessidade de largura de banda estar a aumentar de um modo transversal no mundo das telecomunicações, certos serviços/entidades necessitam de maiores velocidades tanto em termos de download como em termos de upload. E então fácil de perceber que consumidores diferentes têm necessidades diferentes. E necessário encontrar uma arquitectura que agrade a quem necessita de maiores larguras de banda mas também a quem não necessita de um aumento significativo e que, não está disposto a pagar por este. Existem neste momento tecnologias que ainda não foram implementadas em grandes escalas, como o caso de Next Generation Passive Optical Network (NG-PON2), porque não simbolizam um retorno financeiro para as grande operadores, uma vez que o número de potenciais consumidores de tais velocidades ainda não e substancialmente grande. E necessário encontrar uma solução que não so englobe as novas tecnologias como também as já existentes. Com o objectivo de se encontrar um solução para os problemas acima referidos, este trabalho assenta na elaboração de um Circuito integrado fotonico que visa ser um transrecetor de uma arquitetura multi-tecnologia em que irão ser incorporadas tecnologias como Video-Overlay, 10 Gigabit-capable Passive Optical Network (XG-PON) e NG-PON2. Esta dissertação apresenta uma abordagem as Redes Oticas Passivas e também um estudo feito aos componentes usados no transreceptor usando os programas Aspic e VPI Photonics . Porém ser a apresentado o desenho final do transreceptor que ser a usado numa Optical Network Unit(ONU)

Mecanismos de tuning em redes de acesso óticas

Mestrado em Engenharia Electrónica e TelecomunicaçõesO principal tema abordado neste trabalho e a tecnologia a ser utilizada em redes passivas oticas de nova gera c~ao, nomeadamente o TWDM e o PtP WDM, com um foco em especial nos mecanismos de tunabilidade a ser usados nas arquiteturas de rede mencionadas. Come cou por ser feita uma abordagem geral ao tema, um "overview" a recomenda c~ao para o NG-PON2 e apresentada, assim como uma revis~ao a transceivers incolores, componentes essenciais nas arquitecturas do NG-PON2. Tendo em conta o n vel de precis~ao apresentada, tr^es tipos de ONUs s~ao de nidas nos standards do NG-PON2, e os mecanismos de tuning necess arios para lidar com os diferentes tipos de ONU s~ao tamb em apresentados. Foi caracterizado um laser sintoniz avel (DFB) tendo em vista a sua utiliza c~ao numa ONU do NG-PON2, os parametros avaliados foram: tempo de sintoniza c~ao, excurs~ao espectral e precis~ao de tuning. As t ecnicas de medi c~ao s~ao apresentadas bem como os resultados obtidos.The main issue addressed in this work are the technologies to be employed in the next-generation passive optical networks, including TWDM-PON and PtP WDM, with a particularly focus on the tuning mechanisms featuring the aforementioned network architectures. A general approach to the topics was carried out, by making an overview the NG-PON2 recommendation, a review to colorless transceivers is presented as well, essential components on the NG-PON2 architectures. Three types of ONUs are de ned in NGPON2 standards, by taking into account the accuracy level of the ONU Tx, tuning mechanisms necessary to to deal with the di erent kind of ONUs are presented as well A tunable DFB laser was characterized, considering its utilization on a NGPON2 ONU. The evaluated parameters are: tuning time, spectral excursion and tuning accuracy. The setups utilized for the measurements are presented as well as the results

Photonic devices for next generation fiber-to-the-home access network

It would be unaffordable if the WDM-PON technologies were directly applied for massive deployment. Hence, the potential WDM-PON is to be integrated and improved in order to adapt it for NGPON and the future 5G. The UDWDM-PON can be considered as an ultimate solution for the next-generation access network capable of providing unlimited bandwidth for each user, thanks to the coherent detection. Plenty of scientists have believed that it is crucial to increase the operating speed and maximum reach of WDM-PON, while it has no sense if people achieve them without a ordable cost. In order to apply them cost-effciently, the system should require colorless ONUs and bidirectional systems. It is desired that the whole system use modulators on a low bias consumption, even limit the number of amplifiers. However, for bidirectional transmission the backscattering effects would limit the performance if we want to reuse the carrier from OLT. So, we should design a method to separate the wavelength between upstream and downstream. The traditional UDWDM-PON uses 2 laser at ONU, in this thesis, the single-DFB based ONUs are presented with integrated devices. What is the most plausible configuration? The photonic devices such as RSOA, DEML, FML with advanced configurations are presented in this thesis with different applications. The proposed thesis includes these parts: key devices for WDM-PON and the chirp parameters of these integrated photonic devices are measured, the polarization independent RSOA with different applications is also included, demonstration of dual output DEML with bidirectional coherent UDWDM-PON transmission, mitigating residual AM of DEML for phase modulation, and fast tuning for the UDWDM channel via FML are described.Por sus altos requerimientos técnicos, sería inasumible aplicar las tecnologías WDM-PON directamente para el despliegue masivo de Fiber-to-the-Home de nueva generación. Por lo tanto, el potencial se WDM-PON se debe integrar y mejorar con el fin de adaptarlo para NGPON y el futuro 5G. Hoy dia, operadores, usuarios y científicos, ven crucial augmentar la velocitat de funcionament y el alcance de las redes de acceso PON, si bien no tiene sentido conseguirlo con un coste inasequible. El UDWDM-PON puede considerarse como una solución definitiva para la red de acceso de próxima generación, capaz de proporcionar ancho de banda ilimitado para cada usuario, gracias a la detección coherente, por lo que en esta tesis se aborda su realización con un coste e integración prácticos. Con el fin de aplicarlos de manera rentable, el sistema debería exigir a las ONU que sean idénticas, si láseres preseleccionados o incoloros, y ser bidireccionales. Se desea que el conjunto de moduladores del sistema tengan en un bajo consumo, e incluso limitar el número de amplificadores. Sin embargo, para la transmisión bidireccional los efectos de retrodispersión limitarían el rendimiento si queremos volver a utilizar la portadora generada en la OLT. Por lo tanto, debemos diseñar un método para separar la longitud de onda en las transmisiones de bajada y de retorno del usuario a la central. El tradicional UDWDM-PON utiliza 2 láseres en la ONU; en esta tesis, las ONUs usan dispositivos integrados basados en un sólo DFB. ¿Cuál es la configuración más plausible? Los dispositivos fotónicos como RSOA, DEML, FML con configuraciones avanzadas se presentan en esta tesis con diferentes aplicaciones, que resuelven distintos problemas técnicos. La tesis incluye las siguientes partes: análisis y medida de dispositivos fotónicos clave para WDM-PON con modulación de fase, la independencia a la polarización de RSOA con diferentes aplicaciones, demostración de DEML con doble salida para transmisión bidireccional coherente UDWDM-PON, mitigación de AM residual de DEML para la modulación de fase, y la sintonía rápida de canal de UDWDM a través de FML.Postprint (published version

Delta-Sigma Digitization and Optical Coherent Transmission of DOCSIS 3.1 Signals in Hybrid Fiber Coax Networks

We first demonstrate delta-sigma digitization and coherent transmission of data over cable system interface specification (DOCSIS) 3.1 signals in a hybrid fiber coax (HFC) network. Twenty 192-MHz DOCSIS 3.1 channels with modulation up to 16384QAM are digitized by a low-pass cascade resonator feedback (CRFB) delta-sigma analog-to-digital converter (ADC) and transmitted over 80 km fiber using coherent single-λ 128-Gb/s dual-polarization (DP)-QPSK and 256-Gb/s DP-16QAM optical links. Both one-bit and two-bit delta-sigma digitization are implemented and supported by the QPSK and 16QAM coherent transmission systems, respectively. To facilitate its practical application in access networks, the coherent system is built using a low-cost narrowband optical modulator and RF amplifiers. Modulation error ratio (MER) larger than 50 dB is successfully demonstrated for all 20 DOCSIS 3.1 channels, and high order modulation up to 16384QAM is delivered over fiber for the first time in HFC networks. The raw DOCSIS data capacity is 54 Gb/s with net user information ~45 Gb/s. Moreover, the bit error ratio (BER) tolerance is evaluated by measuring the MER performance as BER increases. Negligible MER degradation is observed for BER up to 1.5 × 10−6 and 1.7 × 10−4, for one-bit and two-bit digitization, respectively