There are 1 files which have been withheld at the author's request. Master of Science in Engineering - Engineering / Modelling of telecommunications access networks which concentrate traffic is essential for architectural studies, design and operational efficiency. This work develops the concept of an Intermediate Services Access Network (ISAN) that represents an enhanced narrowband synchronous transfer mode access network which provides an evolutionary step from the existing POTS and N-ISDN access networks to the Fibre to the x (FTTx) networks. Models of the ISAN are developed to support architectural and traffic studies. Generic components are identified from a study of several typical ISAN network architectures. The components include intelligent nodes, transmission links and exchange interfaces. The modelling methodology used seeks firstly to identify resources in the access network and then model them as object classes. Entity-Relationship diagram techniques, defined by the International Telecommunications Union, are used in this work to identify, decompose and represent components in an access network. Recurring components in this work are termed generic components and have attributes that make them reusable. The classes developed consist of generic classes, and technology or application specific classes. Software classes are developed to represent traffic sources with selectable parameters including Poisson arrivals, negative exponential or lognormal holding times and asymmetric originating and terminating models. The identified object classes are implemented using the object-oriented simulation language MODSIM III. An existing unidirectional ring network is simulated to quantify the traffic performance of this type of network under telephone traffic conditions. The ring network is further developed to enhance traffic capacity and performance under link failure conditions. As an economic consideration, this hypothetical ring network uses a single backup link in the event of link failure. The network is simulated with different types of types of traffic (telephone, payphone and Internet dial-up traffic) and under link failure conditions to establish the grade of service.

Esta investigación está conducida a la resolución del problema de encontrar soluciones rentables para el despliegue de redes de fibra hasta el hogar (Fibre to the Home - FTTH). En una red de FTTH, el equipo transmisor-receptor de usuario así como el despliegue de la fibra en la llamada 'última milla' son las barreras principales. Una topología que consiste en hacer llegar una única fibra para dirigirse a cada usuario reduce la cantidad de fibra requerida. Por otro lado, los componentes ópticos pasivos alivian los requisitos de mantenimiento de la red de acceso. El efecto del backscattering de Rayleigh se ha identificado como la interferencia más crítica de este tipo de transmisión, el efecto sobre el funcionamiento del sistema y las investigaciones de posibles soluciones al mencionado problema son centro de estudio de esta tesis. Los experimentos realizados, revelan que, a pesar de la interferencia causada por del effecto Rayleigh no se puede eliminar totalmente, hay diferentes técnicas capaces de atenuar dicho efecto. El uso de los amplificadores ópticos semiconductores para implementar las funciones de transmisión-recepción agrega simplicidad al diseño de red en términos de transparencia de la longitud de onda y gracias a las capacidades de la amplificación de esta familia de dispositivos.Los resultados experimentales presentaron en este trabajo demuestran con éxito la modulación y la detección a 1Gbit/s y 2.5Gbit/s con los dispositivos basados en semiconductores, en enlaces de hasta 30km e incluso de hasta 50km de longitud. Nuevos prototipos son potencialmente capaces de transmitir a 10Gbit/s. Estructuras reflectoras basadas en amplificadores ópticos semiconductores reflectores son los candidatos mas adecuados.Éstos, realizan funciones de transmisión eficientemente y proporcionan la amplificación adecuada. Sin embargo, es necesario el diseño de nuevos diseños capaces de transmitir datos a una velocidad mayor. Una estrategia de comunicación bidireccional mediante una única fibra es la arquitectura más interesante los términos de reducción de costes por usuario (CAPEX). Por estos motivos, la ONU se convierte en un elemento clave en redes de acceso y un área muy interesante de investigación. Para una evolución exitosa de FTTH el diseño de la unidad de red debe ser simple, robusto, flexible y bajo coste para el cliente final. La traducción de los requisitos anteriormente mencionados en especificaciones técnicas establece las pautas siguientes para el diseño del FTTH ONU- Una única fibra por cada usuario para reducir tamaño de la red de acceso- Independencia de la longitud de onda para permitir una operación transparente en redes WDM- Que no haya fuente de luz activa en las dependencias de usuario para prevenir el mantenimiento en el lado del usuario- Con amplificación y así poder aumentar el número de usuarios y alcanzar mayores distanciasDe esta manera, el objetivo principal de esta tesis es la investigación de unidades ópticas de red reflectoras, especialmente las basadas en amplificadores ópticos de semiconductor, así como su funcionamiento en redes de FTTH, basadas en tecnología de acceso WDM-PON. Esto implica fundamentalmente- Identificar arquitecturas y dispositivos propuestos por medio de la investigación del trabajo publicado relacionado y destacar limitaciones y requisitos de los sistemas actuales- evaluar las diversos alternativas para la ONU y para proponer soluciones mejoradas, demostradas con simulaciones y experimentos - investigar limitaciones posibles de los sistemas transmisión bidireccionales y desarrollar soluciones para la mejora de la transmisión- desarrollar descripciones analíticas de las señales implicadas en la transmisión / This research was conducted to deal with the problem of finding cost-effective solutions for Fibre-to-the-Home (FTTH) network deployment. In the FTTH network, the transceiver at the user premises and the deployment of fibre at the last mile are the major barriers. A single-fibre topology to address each user reduces the amount of fibre required; passive optical components alleviate maintenance requirements in the access network.The Rayleigh backscattering effect is identified as the most critical crosstalk in such transmission, the effect on the system performance and the investigations of possible solutions are presented in this thesis. The studies reveal that despite the Rayleigh backscattering crosstalk can not be totally eliminated, several techniques can mitigate the effect.The use of the semiconductor optical amplifiers to feature transceiver tasks at the user premises adds simplicity to the network design in terms of wavelength transparency and amplification capabilities. We propose implementations with semiconductor amplifiers and test modulation and detection potentials inside the optical network. The experimental results successfully demonstrate modulation and detection at 1Gbit/s and 2.5Gbit/s with semiconductor-based devices, in links of 30km and even though of 50km length; bit rate of 10Gbit/s is feasible with novel prototypes as well. Reflective structures based on reflective semiconductor optical amplifiers are potential candidates, as they perform transmission functions efficiently and provide adequate amplification however, it is necessary the design of further structures capable of transmitting at a higher bit rates.

“Connected society” where everything and everyone are connected at any time and on any location brings new challenges for the network operators. This leads to the need of upgrading the transport networks as the segment of Internet infrastructure connecting the fixed users and mobile base stations to the core/aggregation in order to provide high sustainable bandwidth, as well as supporting a massive number of connected devices. To do this, operators need to change the way that access networks are currently deployed. The future access network technologies will need to support very high capacity and very long distances, which are the inherited characteristics of optical transmission. Hence, optical fiber technology is recognized as the only future proof technology for broadband access. Capacity upgrade in the access networks can lead to a huge capacity demand in the backbone network. One promising solution to address this problem, is to keep the local traffic close to the end users as much as possible, and prevent unnecessary propagation of this type of traffic through the backbone. In this way, operators would be able to expand their access network without the significant capacity upgrade in the higher aggregation layers. Motivated by this need, a comprehensive evaluation of optical access networks is carried out in this thesis regarding ability of accommodating local traffic and amount of possible saving in the backbone by implementing locality awareness schemes. Meanwhile, next generation optical access (NGOA) networks have to provide high capacity at low cost while fulfilling the increasing reliability requirements of future services and customers. Therefore, finding cost-efficient and reliable alternative for future broadband access is one of the most important contributions of this thesis. We analyzed the tradeoff between the cost needed to deploy backup resources and the reliability performance improvement obtained by the proposed protection mechanism. Among different NGOA architectures, hybrid time and wavelength division multiplexing passive optical network (TWDM PON) is considered as a proper candidate providing high capacity and large coverage. Therefore, this approach is further analyzed and several tailored protection schemes with high flexibility are proposed to statisfy different requirements from the residential and business users in the same PON.  The work carried out in the thesis has proved that TWDM PON can also offer high reliability performance while keeping the network expenditures at an acceptable level. Considering some other advantages such as low power consumption and high flexibility in resource allocation of this architecture, it has high potential to be the best candidate for NGOA networks.  Moreover, new deployments of radio access networks supporting the increasing capacity demand of mobile users lead to the upgrade of the backhaul segment as a part of broadband access infrastructure. Hence, this thesis also contributes with a comprehensive techno-economic evaluation methodology for mobile backhaul. Several technologies are investigated in order to find the most cost-efficient solution for backhauling the high capacity mobile networks.  Finally, a PON-based mobile backhaul with high capacity and low latency has been proposed for handling coordinated multipoint transmission systems in order to achieve high quality of experience for mobile users. / <p>QC 20150320</p>

The idea of a Media Frame network (MFN) was proposed very recently for solving the explosively growing demand for end-to-end large file transfers. This networking method combines the advantage of high transmission speed from optical networks and flexibility and fast header parsing from electronic networks. The MFN is based on very large data units or media frames (MF) compared to IP packets. Due to the logical continuity, transporting data in a media frame network largely reduces the power consumption in the intermediate nodes and routers. Currently the backbone of media frame network has been studied. The remaining challenge is to devise a system solving the problem of transporting MFs through access networks (i.e., the last mile) connecting customers to the backbone networks. To our knowledge, no other research activity regarding this challenge has been reported. If this challenge is overcome and if the overall concept is accepted, the MFN could be a very important step in the evolution of the Internet. This thesis focuses mainly on the access network. For the first time, a solution is proposed to establish the ability to transport media frames over a standard PON (e.g. Passive Optical Network) architecture. Because of the unique properties of the media frame network, the physical layer model and transport protocols must be rebuilt. Referring to the ITU-T G.987 recommendations, the physical layer is built based on the XGPON specification. In this thesis, the initialization protocols, bandwidth allocation plan, OLT-ONU (OLT: Optical Line Terminal, e.g. central office. ONU: Optical Network Unit, e.g. customer side box) negotiation protocols are designed. Different schemes for each protocol are proposed, with simulation support based on Omnet++. For the transmission of a 7GB file on average, different transparency degrees under different traffic conditions are compared, and the tradeoffs among essential factors are investigated. / Graduate

Future generation cellular networks are expected to deliver an omnipresent broadband access network for an endlessly increasing number of subscribers. Long term Evolution (LTE) represents a significant milestone towards wireless networks known as 4G cellular networks. A key feature of LTE is the implementation of enhanced Radio Resource Management (RRM) mechanism to improve the system performance. The structure of LTE networks was simplified by diminishing the number of the nodes of the core network. Also, the design of the radio protocol architecture is quite unique. In order to achieve high data rate in LTE, 3rd Generation Partnership Project (3GPP) has selected Orthogonal Frequency Division Multiplexing (OFDM) as an appropriate scheme in terms of downlinks. However, the proper scheme for an uplink is the Single-Carrier Frequency Domain Multiple Access due to the peak-to-average-power-ratio (PAPR) constraint. LTE packet scheduling plays a primary role as part of RRM to improve the system’s data rate as well as supporting various QoS requirements of mobile services. The major function of the LTE packet scheduler is to assign Physical Resource Blocks (PRBs) to mobile User Equipment (UE). In our work, we formed a proposed packet scheduler algorithm. The proposed scheduler algorithm acts based on the number of UEs attached to the eNodeB. To evaluate the proposed scheduler algorithm, we assumed two different scenarios based on a number of UEs. When the number of UE is lower than the number of PRBs, the UEs with highest Channel Quality Indicator (CQI) will be assigned PRBs. Otherwise, the scheduler will assign PRBs based on a given proportional fairness metric. The eNodeB’s throughput is increased when the proposed algorithm was implemented.

Research Doctorate - Doctor of Philosophy (PhD) / The Radio Access Network (RAN) accounts for the major proportion of the UMTS system operating cost. Transmission from radio base station sites contributes a larger part of the RAN operating costs. Selection of suitable transport technologies and proper allocation of network resources are vital from an operator cost optimisation and the Quality of Experience (QoE) points of view. This thesis extensively investigated the performance of a RAN to support multimedia traffic on a HSDPA air interface. Transport network layer of a future RAN could be based on a number of transport protocols such as ATM, IP and Ethernet. With the increasing traffic volume and diversity the efficiencies of IP and Ethernet based RAN could increases significantly due to the use of larger payloads and simpler resource allocation techniques. Also, on IP and Ethernet based links relatively fewer overhead bits are transmitted compared to an ATM based link. Both the IP and Ethernet based links appear to perform better under heavy traffic load conditions. An IP based link could perform better than an Ethernet based link when an IP header compression technique is used. An Ethernet based link is an alternative transport technique for the UTRAN transport network due to its flexibility, economy and bandwidth efficiency. The HSDPA (High Speed Downlink Packet Access) is considered to be one of the initial evolutionary steps to enhance the data rate, and QoS of downlink data and multimedia services for the evolved UMTS network. It can provide high data rate up to 28.8 Mbps on the downlink shared channel using the packet access technique. A HSDPA network can dynamically adjust a connection data rate to match radio conditions to ensure the highest possible data rate for different type of traffic. Inappropriate RAN capacity allocation could lead to low radio resource or RAN resource utilizations. In this thesis, a Markov chain based analytical model has been developed to study the interaction between the air interface and the RAN for a HSDPA network. The analytical model was used to study interactions of RAN transport protocols, flow control techniques and the air interface transmission conditions. Further a simulation model was developed to investigate the relationship between the HSDPA air interface and its RAN parameters. Another important issue in the HSDPA network design is the scheduling algorithm used at the Node-B. A scheduling algorithm plays a key role in allocating a RAN’s network resources. Impacts of scheduling algorithms are studied in this work using a simulation model. Based on the study of the HSDPA air interface and its RAN parameter interactions this work has developed an adaptive resource management algorithm, which uses the measured air interface information to allocate the corresponding connection data rate on the Iub link. The developed algorithm reduces RAN resource requirements while increasing the air interface resource utilization and QoS of connections.

京都大学 / 0048 / 新制・課程博士 / 博士(情報学) / 甲第21216号 / 情博第669号 / 新制||情||115(附属図書館) / 京都大学大学院情報学研究科通信情報システム専攻 / (主査)教授 守倉 正博, 教授 大木 英司, 教授 梅野 健 / 学位規則第4条第1項該当 / Doctor of Informatics / Kyoto University / DFAM

Optical fibre has become the dominant theme of transmission in long haul, high data rate communication systems due to its tremendous bandwidth and low loss. Radio over Fibre (RoF) technology facilitates the seamless integration between wireless and optical communication systems and found to be the most promising solution to meet the exponential bandwidth demands expected for the upcoming years. However, the main bit-rate/distance limitation in RoF systems is the chromatic dispersion. In this thesis, the two generations of RoF technologies, namely Analogue RoF (ARoF) and Digital RoF (DRoF) are investigated. The overall aim of this research is to optimise the optical bandwidth utilisation of these two approaches for a typical transmission of the fronthaul link proposed in the next generation Centralised Radio Access Network (C-RAN). Consequently, a number of physical layer design scenarios for the optimised transmission of the Radio Frequency (RF) signals over a Standards Single Mode Fibre (SSMF) are demonstrated. Firstly, for an ARoF transmission, where the analogue RF signals are transported over SSMF using an optical carrier, a bidirectional link transmitting four Downlink/Uplink channels in a chromatic dispersion limited scenario is designed. Simulation results have shown a clear constellation diagram of a 2.5 Gb/s RF signal transmission over 120 km fibre length. Secondly, a DRoF system with reduced optical bandwidth occupancy is proposed. This system employs an optical Duobinary transmission to the digitised RF signal at the transmitter side to reduce its spectrum and to address the chromatic dispersion effect, simultaneously. Simulation results demonstrate the capability of the proposed system to maintain high-quality transmission of the digitised signals over 70 km of fibre distance without dispersion compensation requirements. Finally, an advanced DRoF transmission link based on integrating digital Optical Single Sideband (OSSB) transmission with Duobinary encoding scheme is designed. Simulation results have clearly verified system's robustness against transmission impairments and have better performances in terms of the obtained BER and EVM with respect to the 3GPP standardised values. Moreover, the results show that both transmission distance and power budget are furtherly improved in comparison with two other digital transmission scenarios.

Rapid changes in population distribution across Canada and the introduction of new telecommunication services to the consumer market have resulted in a number of significant challenges for existing network infrastructure. Fast growing populations in metropolitan regions require high density access networks to meet the growing need for bandwidth that results. Furthermore, new services such as high definition TV, online gaming and real-time video teleconferencing are becoming increasingly popular among consumers. These services require higher bandwidth to be available to end users. Changes in the Canadian economy will soon lead to a transition in Canadian industry from manufacturing to services and exploration of natural resources. This will create opportunities for new industrial development and growth in northern regions. Expanding industrialization towards northern Canada will require deployment of reliable telecommunication infrastructure. The combination of open source software, Linux operating system and Personal Computer (PC) based hardware platform is proposed to become the foundation for low cost and flexible technology that will provide transition towards all-optical infrastructures. An innovative prototype of a low-cost optical gigabit Ethernet switch is presented and its benchmark results are discussed. Scalability of the switch and its future applications in optical networks are studied. A prototype of a software based data encapsulation system was designed and implemented in a PC based platform, and its performance was evaluated using real data that was captured in commercial LAN. Semiconductor optical amplifiers (SOA) are studied as a building block in next generation switching devices for all-optical access networks. A prototype of an SOA-based low-cost optical switching device with implemented FPGA based controlling mechanism is presented and its characteristics are discussed. SOA is also studied as an energy efficient optical amplifier that can be deployed in end user facilities. The presented results provide proof of concept of a low cost flexible platform that can be used to design and build network devices to facilitate the transition of existing telecommunication networks towards next generation optical access infrastructure.

La interfaz radio de los sistemas de comunicaciones móviles es normalmente considerada como la única limitación de capacidad en la red de acceso radio. Sin embargo, a medida que se van desplegando nuevas y más eficientes interfaces radio, y de que el tráfico de datos y multimedia va en aumento, existe la creciente preocupación de que la infraestructura de transporte (backhaul) de la red celular pueda convertirse en el cuello de botella en algunos escenarios. En este contexto, la tesis se centra en el desarrollo de técnicas de gestión de recursos que consideran de manera conjunta la gestión de recursos en la interfaz radio y el backhaul. Esto conduce a un nuevo paradigma donde los recursos del backhaul se consideran no sólo en la etapa de dimensionamiento, sino que además son incluidos en la problemática de gestión de recursos. Sobre esta base, el primer objetivo de la tesis consiste en evaluar los requerimientos de capacidad en las redes de acceso radio que usan IP como tecnología de transporte, de acuerdo a las recientes tendencias de la arquitectura de red. En particular, se analiza el impacto que tiene una solución de transporte basada en IP sobre la capacidad de transporte necesaria para satisfacer los requisitos de calidad de servicio en la red de acceso. La evaluación se realiza en el contexto de la red de acceso radio de UMTS, donde se proporciona una caracterización detallada de la interfaz Iub. El análisis de requerimientos de capacidad se lleva a cabo para dos diferentes escenarios: canales dedicados y canales de alta velocidad. Posteriormente, con el objetivo de aprovechar totalmente los recursos disponibles en el acceso radio y el backhaul, esta tesis propone un marco de gestión conjunta de recursos donde la idea principal consiste en incorporar las métricas de la red de transporte dentro del problema de gestión de recursos. A fin de evaluar los beneficios del marco de gestión de recursos propuesto, esta tesis se centra en la evaluación del problema de asignación de base, como estrategia para distribuir el tráfico entre las estaciones base en función de los niveles de carga tanto en la interfaz radio como en el backhaul. Este problema se analiza inicialmente considerando una red de acceso radio genérica, mediante la definición de un modelo analítico basado en cadenas de Markov. Dicho modelo permite calcular la ganancia de capacidad que puede alcanzar la estrategia de asignación de base propuesta. Posteriormente, el análisis de la estrategia propuesta se extiende considerando tecnologías específicas de acceso radio. En particular, en el contexto de redes WCDMA se desarrolla un algoritmo de asignación de base basado en simulatedannealing cuyo objetivo es maximizar una función de utilidad que refleja el grado de satisfacción de las asignaciones respecto los recursos radio y transporte. Finalmente, esta tesis aborda el diseño y evaluación de un algoritmo de asignación de base para los futuros sistemas de banda ancha basados en OFDMA. En este caso, el problema de asignación de base se modela como un problema de optimización mediante el uso de un marco de funciones de utilidad y funciones de coste de recursos. El problema planteado, que considera que existen restricciones de recursos tanto en la interfaz radio como en el backhaul, es mapeado a un problema de optimización conocido como Multiple-Choice Multidimensional Knapsack Problem (MMKP). Posteriormente, se desarrolla un algoritmo de asignación de base heurístico, el cual es evaluado y comparado con esquemas de asignación basados exclusivamente en criterios radio. El algoritmo concebido se basa en el uso de los multiplicadores de Lagrange y está diseñado para aprovechar de manera simultánea el balanceo de carga en la intefaz radio y el backhaul.