自2007年國家通訊傳播委員會（NCC）發放六張無線寬頻接取執照（Wireless Broadband Access, WBA）後，至今台灣六家WiMAX營運商已全數開台，台灣WiMAX產業正式進入商轉營運階段。然而由於WiMAX為一新興產業，產業之遊戲規則仍待確立，加上其他4G等行動上網技術的競爭下，各家WiMAX營運商之背景與資源分部情形無法立即分出競爭勝負，還需端看營運商如何對自身資源作出適當的評估與利用，以發展合適之競爭策略，才能達到產業競爭優勢。 因此本研究從資源基礎理論的角度出發，透過個案研究法，以得到南區執照的威達雲端電訊進行研究，了解威達雲端在發展WiMAX產業上，對資源的運用。本研究擬探討之四個問題為：(1) 威達雲端電訊當初選擇進入WiMAX產業的評估與原因為何？ (2) 威達雲端電訊在發展WiMAX上的核心資源與資源缺口各為何？(3) 威達運端電訊在進入WiMAX此一新興產業時，如何針對本身資源的優劣勢發展出適當的競爭策略？(4) 威達雲端電訊相較於其他WiMAX營運商，有何競爭優勢？(5) LTE與WiMAX陣營在未來發展上各有何資源優勢，WiMAX營運商該如何面對LTE的挑戰？ 研究結果發現：(1) 威達雲端最大核心資源優勢為本身擁有大量內容及相關經驗、基礎顧客群，與光纖網路之布建。(2) 威達雲端主要資源缺口為資金、相關人才與電信發 展經驗與技術。(3) 威達雲端有效利用具延展性之資源，將資源做延伸與強化，進行多角化發展，推出新產品組合及服務，以達到綜效與擴大整體經濟規模。(4) 威達雲端進行策略聯盟等合作方式進行資源之補足，尤其是以吸取電信相關布建經驗與技術為主。(5) 相較於其他相關業者，威達雲端以較低成本提供WiMAX服務，並將WiMAX技術與其他資源結合，推出差異化之服務為其競爭之優勢。 / Since the National Communications Commission released six operating licenses of Wireless Broadband Access (WBA) in 2007, the six WiMAX operators in Taiwan have all completed deployment for commercial services by the end of 2010. However, as an emerging industry, WiMAX technology and its industry have not fully matured. Meanwhile, WiMAX is facing the rival fourth generation wireless technology . Under the circumstance, in order to create competitive advantages, WiMAX operators should lie primarily in the application of the bundle of valuable resources at the firm's disposal. Therefore, this paper, takes the Resource-Based Theory as the analysis structure, with reference to the case of licensed WiMAX operator “Vee Telecom Multimedia Co,” (or simply Vee) attempts to find out how the operator utilizes its core resource to carry out the competitive strategy. The purposes of this thesis include: (1) The reason why Vee chose to enter WiMAX industry; (2) The core resources and recourse gaps of Vee; (3) When entering the WiMAX industry, how Vee carry out the strategic deployment of its resources; (4) Compare to other WiMAX operators, what competitive advantages does Vee have; (5) What core resources do WiMAX and LTE operators have? How do WiMAX operators face the challenge of LTE technology? The results showed that (1) the core resources of Vee are contents, customer base, and the fiber network. (2) the resource gaps of Vee are funds, talent, experiences in telecommunications. (3) with the effective use of scalable resources, Vee extends and strengthens the resources to develop new products and services portfolio, in order to achieve synergies and increase economies of scale. (4) using strategic alliances and other cooperative approach to fill the resource gaps, especially the deployment experiences in telecommunications. (5) compared to other operators, Vee provides WiMAX services at a lower cost and offers differentiated services to gain its competitive advantage.

This work concentrates on the application of diversity techniques and space time block coding for future high speed mobile wireless communications on multicarrier systems. At first, alternative multicarrier kernels robust for high speed doubly-selective fading channel are sought. They include the comparisons of discrete Fourier transform (DFT), fractional Fourier transform (FrFT) and wavelet transform (WT) multicarrier kernels. Different wavelet types, including the raised-cosine spectrum wavelets are implemented, evaluated and compared. From different wavelet families, orthogonal wavelets are isolated from detailed evaluations and comparisons as suitable for multicarrier applications. The three transforms are compared over a doubly-selective channel with the WT significantly outperforming all for high speed conditions up to 300 km/hr. Then, a new wavelet is constructed from an ideal filter approximation using established wavelet design algorithms to match any signal of interest; in this case under bandlimited criteria. The new wavelet showed better performance than other traditional orthogonal wavelets. To achieve MIMO communication, orthogonal space-time block coding, OSTBC, is evaluated next. First, the OSTBC is extended to assess the performance of the scheme over extended receiver diversity order. Again, with the extended diversity conditions, the OSTBC is implemented for a multicarrier system over a doubly-selective fading channel. The MIMO-OFDM systems (implemented using DFT and WT kernels) are evaluated for different operating frequencies, typical of LTE standard, with Doppler effects. It was found that, during high mobile speed, it is better to transmit OFDM signals using lower operating frequencies. The information theory for the 2-transmit antenna OSTBC does not support higher order implementation of multi-antenna systems, which is required for the future generation wireless communications systems. Instead of the OSTBC, the QO-STBC is usually deployed to support the design of higher order multi-antenna systems other than the 2-transmit antenna scheme. The performances of traditional QO-STBC methods are diminished by some off-diagonal (interference) terms such that the resulting system does not attain full diversity. Some methods for eliminating the interference terms have earlier been discussed. This work follows the construction of cyclic matrices with Hadamard matrix to derive QO-STBC codes construction which are N-times better than interference free QO-STBC, where N is the number of transmit antenna branches.

With increasing demands on network reliability and speed, network suppliers need to effectivize their communications algorithms. Frequency measurements are a core part of mobile network communications, increasing their effectiveness would increase the effectiveness of many network processes such as handovers, load balancing, and carrier aggregation. This study examines the possibility of using supervised learning to predict the signal of inter-frequency measurements by investigating various learning algorithms and pre-processing techniques. We found that random forests have the highest predictive performance on this data set, at 90.7\% accuracy. In addition, we have shown that undersampling and varying the discriminator are effective techniques for increasing the performance on the positive class on frequencies where the negative class is prevalent. Finally, we present hybrid algorithms in which the learning algorithm for each model depends on attributes of the training data set. These algorithms perform at a much higher efficiency in terms of memory and run-time without heavily sacrificing predictive performance.

Le développement de la radio logicielle fait suite à l’évolution rapide du domaine des télécommunications. Les besoins en performance et en dynamicité ont donné naissance à des MPSoC dédiés à la radio logicielle. La spécialisation de ces MPSoC rend cependant leur pro- grammation et leur vérification complexes. Des travaux proposent d’atténuer cette complexité par l’utilisation de paradigmes tels que le modèle de calcul flot de données. Parallèlement, le besoin de modèles flexibles et vérifiables a mené au développement de nouveaux modèles flot de données paramétriques. Dans cette thèse, j’étudie la compilation d’applications utilisant un modèle de calcul flot de données paramétrique et ciblant des plateformes de radio logicielle. Après un état de l’art du matériel et logiciel du domaine, je propose un raffinement de l’ordonnancement flot de données, et présente son application à la vérification des tailles mémoires. Ensuite, j’introduis un nouveau format de haut niveau pour définir le graphe et les acteurs flot de données, ainsi que le flot de compilation associé. J’applique ces concepts à la génération de code optimisé pour la plateforme de radio logicielle Magali. La compilation de parties du protocole LTE permet d’évaluer les performances du flot de compilation proposé. / The emergence of software-defined radio follows the rapidly evolving telecommunication domain. The requirements in both performance and dynamicity has engendered software- defined-radio-dedicated MPSoCs. Specialization of these MPSoCs make them difficult to program and verify. Dataflow models of computation have been suggested as a way to mi- tigate this complexity. Moreover, the need for flexible yet verifiable models has led to the development of new parametric dataflow models. In this thesis, I study the compilation of parametric dataflow applications targeting software-defined-radio platforms. After a hardware and software state of the art in this field, I propose a new refinement of dataflow scheduling, and outline its application to buffer size’s verification. Then, I introduce a new high-level format to define dataflow actors and graph, with the associated compilation flow. I apply these concepts to optimised code generation for the Magali software-defined-radio platform. Compilation of parts of the LTE protocol are used to evaluate the performances of the proposed compilation flow.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-12-16T13:58:28Z No. of bitstreams: 2 Tese - Flávio Geraldo Coelho Rocha - 2016.pdf: 4809831 bytes, checksum: e575d503488bc0e0cb8f1a1b3478d982 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2016-12-16T16:59:35Z (GMT) No. of bitstreams: 2 Tese - Flávio Geraldo Coelho Rocha - 2016.pdf: 4809831 bytes, checksum: e575d503488bc0e0cb8f1a1b3478d982 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-12-16T16:59:35Z (GMT). No. of bitstreams: 2 Tese - Flávio Geraldo Coelho Rocha - 2016.pdf: 4809831 bytes, checksum: e575d503488bc0e0cb8f1a1b3478d982 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-11-22 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / In this work, in order to describe network traffic characteristics, such as long-range dependence among samples, self-similarity and multiscale behavior, we propose a Multifractal Adaptive Model based on a multiscale cascade in the Wavelet Domain. We compare the proposed model performance with those of other models presented in the literature. It is also proposed an envelope process for the network traffic that takes into account parameters of the Multifractal Adaptive Model. Furthermore, we derive an equation in order to estimate the buffer overflow probability for both a simplified communication system with a single server, single queue and finite buffer, and to a wireless network multiuser scenario based on OFDM technology. To this end, we consider the service curve of the round-robin scheduling algorithm of the OFDM network. Taking into account the envelope process and the service curve we obtain, through the Network Calculus theory, the maximum delay experienced by users of the OFDM network. Moreover, assuming a similar network scenario to an LTE network, we propose a joint channel-aware and queue-aware resource scheduling algorithm. Based on the presented scheduler, we propose a minimum service curve for the LTE user and through this we propose an approach to accomplish maximum delay guarantee. / Neste trabalho, com o objetivo de descrever características do tráfego de redes, tais como longa-dependência entre amostras, autossimilaridade e comportamento multiescala, propõe-se um Modelo Multifractal Adaptativo baseado em uma cascata multiescala no domínio Wavelet. O desempenho do modelo proposto é comparado a outros modelos presentes na literatura. Também é proposto um processo envelope para o tráfego de redes que leva em consideração parâmetros do Modelo Multifractal Adaptativo proposto. Além disso, deduz-se uma equação para o cálculo da probabilidade de transbordo do buffer, tanto para um sistema de comunicação simplificado com servidor único, fila única e buffer finito, quanto para um ambiente multiusuário de rede sem fio baseado na tecnologia OFDM. Para tanto, utiliza-se a curva de serviço do escalonador round-robin da rede OFDM. Utilizando-se do processo envelope e da curva de serviço, obtém-se por meio do Cálculo de Rede a estimativa para o retardo máximo experimentado pelos usuários da rede OFDM. Em seguida, assume-se um ambiente de rede similar ao de uma rede LTE e propõe-se para essa rede um escalonador de recursos sensível às condições do canal de comunicação e à probabilidade de transbordo do buffer. Com base no escalonador apresentado, propõe-se uma curva de serviço mínima para o usuário da rede LTE e por meio dessa, propõe-se uma abordagem para garantia de retardo.

Made available in DSpace on 2016-03-15T19:37:56Z (GMT). No. of bitstreams: 1 BRUNO FERRAZ IZARIO.pdf: 4620887 bytes, checksum: bd842cabfdadb0bcb55e0ea548c9fba5 (MD5) Previous issue date: 2015-08-28 / The Long Term Evolution (LTE) system belongs to the 4th generation phone system. It is standardized by 3GPP and utilizes several technologies to improve the performance of data transmission. This permits flexibility for mobile devices, which enables a high data rate in the range of 50 Mbps to 100 Mbps, and admit access to various multimedia services. The study presents the results of deploying an LTE network in the city of Campinas, São Paulo, Brazil, using the 700 MHz band by comparing it to the 2.5 GHz band. By calculating the budget for the LTE system link is information as possible to highlight throughput and cell coverage radius, and other information. The Radio Mobile software was used for verification of results. / O sistema Long Term Evolution (LTE) pertence ao sistema da 4ª geração de telefonia (4G). Ele é padronizado pelo 3GPP e utiliza diversas tecnologias para melhorar o desempenho de transmissão de dados. O mesmo permite uma flexibilidade para dispositivos móveis, possibilitando uma alta taxa de dados na faixa de 50 Mbps a 100 Mbps, além de admitir acesso a diversos serviços multimídias. O estudo apresenta resultados de implantação de uma rede LTE na cidade de Campinas, São Paulo, Brasil, utilizando a faixa de 700 MHz comparando-a com a faixa de 2,5 GHz. Através do cálculo de link budget para o sistema LTE, é possível destacar informações como throughput e raio da célula de cobertura, além de outras informações. O software radio mobile foi utilizado para fins de comprovação de resultados.

Scheduling is extremely important for modern real-time systems. It enables several programs to run in parallel and succeed with their tasks. Many systems today are real-time systems, which means that good scheduling is highly needed. This thesis aims to evaluate the real-time scheduling algorithm earliest deadline first, newly introduced into the Linux kernel, and compare it to the already existing real-time scheduling algorithms first in, first out and round robin in the context of firm tasks. By creating a test program that can create pthreads and set their scheduling characteristics, the performance of earliest deadline first can be evaluated and compared to the others. / Schemaläggning är extremt viktigt för dagens realtidssystem. Det tillåter att flera program körs parallellt samtidigt som deras processer inte misslyckas med sina uppgifter. Idag är många system realtidssystem, vilket innebär att det finns ett ytterst stort behov för en bra schemaläggningsalgoritm. Målet med det här examensarbetet är att utvärdera schema-läggningsalgoritmen earliest deadline first som nyligen introducerats i operativsystemet Linux. Målet är även att jämföra algoritmen med två andra schemaläggningsalgoritmer (first in, first out och round robin), vilka redan är väletablerade i Linux kärnan. Det här görs med avseende på processer klassificerade som firm. Genom att skapa ett program som kan skapa pthreads med önskvärda egenskaper kan prestandan av earliest deadline first algoritmen utvärderas, samt jämföras med de andra algoritmerna.

Cette thèse s’inscrit dans le domaine de la caractérisation des systèmes de communication sans fil utilisant la diversité des antennes. En effet, ces systèmes permettent de lutter contre les évanouissements des signaux, lorsque le terminal est placé dans un environnement riche en multi-trajets. L’objectif d'une telle recherche est : d’étudier l'association de plusieurs antennes à l'émission et / ou la réception pour améliorer le bilan de liaison, et la capacité des systèmes sans fil, (diminution de BER (Bit Error Rate), augmentation de débit ...). Cette thèse s’intéresse à l'aspect électromagnétique et traitement du signal. Afin de comprendre les phénomènes mis en jeu, et de caractériser les performances du terminal, il doit être placé dans un environnement de propagation multi-trajets contrôlable dans le temps et dans l'espace.Cela nous amène à trouver des méthodes de mesures capables de reproduire des modèles de canaux de propagation réalistes. Dans le cadre de cette thèse la méthode utilisée est la chambre réverbérante. Dans cette thèse, nous nous intéressons à l'aspect temporel. La chambre réverbérante (RC) est considérée comme un outil utile pour émuler des environnements riches en multi-trajets. Dans cette contribution, ce dispositif est utilisé pour émuler des modèles canaux multi-trajets, et évaluer la performance des systèmes de communication sans fil. Cette évaluation est effectuée avec des mesures en temps réel et non temps réel. Parmi les objectifs de cette thèse est d'obtenir un modèle de simulation électromagnétique de la chambre réverbérante basé sur une approche circuit, afin de déterminer la fonction de transfert de canal en fonction des pertes. / This thesis is part of the field of the characterization of wireless communication systems using antennas diversity. Indeed, such systems allow fighting against the signals fading, when the terminal is inside a strong multipath environment. The issue of such research is: to study the association of multiple antennas at transmitting and/or receiving sides to improve the link budget, and the capacity of wireless systems, (decrease of BER (Bit Error Rate), increase of throughput …). This thesis takes an interest to the electromagnetic aspect, and signal processing. In order to understand the involved phenomena, and to characterize the terminal performance, it should be placed in a controlled multipath propagation environment in time, and in space. This brings us to find measurement methodologies able to reproduce models of realistic propagation channels. As part of this thesis the method used is the reverberation chamber. In this thesis we are interested in the time aspect. Reverberation chamber (RC) is considered as a useful tool to emulate rich multipath environments. In this contribution, this device is employed to emulate multi clusters channel models (cluster is defined as a group of multipath), and evaluate performance of wireless communication systems. This evaluation is performed with real time and not-real time measurements. It remains to note that among the objectives set out in this PhD thesis is to obtain electromagnetic simulation model of the reverberation chamber based on circuit approach, in order to determine the channel transfer function versus losses quantities.

Le développement des antennes modales, qui sont des antennes actives reconfigurables en diagramme de rayonnement mais pas en réseaux, a commencé pour pouvoir implémenter le dépointage électronique dans les téléphones portables. Cette solution est généralement réalisée par un réseau d’antennes, ce qui est très difficile, voire impossible, dans un téléphone portable. Le dépointage permettrait d’améliorer le bilan de liaison et d’augmenter le débit des données.Le premier objectif de cette thèse est donc de développer des antennes modales pour la norme LTE. Trois concepts d’antennes modales ont été présentés. Le premier est une antenne de type « folded loop » active reconfigurable par permutation des points d’alimentation et de retour à la masse. Le deuxième propose une architecture pour rassembler l’antenne principale et l’antenne diversité en bas du téléphone, tout en supportant le MIMO et l’agrégation de porteuses, deux des spécificités de la LTE. Le dernier optimise l’utilisation de la seconde antenne des systèmes LTE MIMO pour procéder au dépointage électronique.Ces antennes modales ne peuvent délivrer leur réel potentiel qu’en étant utilisées avec un algorithme de pilotage, qui choisira la configuration ou le mode approprié(e) à la situation. Le second objectif de cette thèse est donc le développement d’algorithmes intelligents de pilotage d’antennes modales. Le premier algorithme développé et breveté par la société Ethertronics a la particularité de prédire à chaque instant quel sera le meilleur mode à l’instant suivant, à l’aide de données en bande de base pour la LTE. Le second algorithme est déterministe et permet d’estimer et de suivre la direction d’arrivée du signal. Il sélectionne ensuite le mode qui possède le meilleur gain dans cette direction, dans le but d’améliorer le bilan de liaison. / The development of modal antennas which are radiation pattern reconfigurable active antennas, but not arrays, started in order to implement beam forming in cellphones. This solution is generally made with an antenna array, which is very difficult, even impossible, in a mobile phone. Beam forming could improve the link budget and increase the data rate. The first aim of this thesis is the development of modal antennas for LTE standard. Three modal antennas concepts were presented. The first one is a reconfigurable “folded loop” active antenna by permutation of feed and ground points. The second one is a solution to gather the main and the diversity antenna in the bottom part of the phone, and to support MIMO and carrier aggregation, which are two features of LTE. The last one optimizes the use of the second antenna in LTE MIMO systems in order to perform beam forming. These modal antennas will provide their real potential only by being used by a driving algorithm which will choose the best mode or configuration according to the situation. So, the second aim of this thesis is the development of smart modal antenna driving algorithms. The first algorithm, developed and patented by Ethertronics, has the specificity to predict, at each moment, which mode will be the best for the next moment, by using baseband data for LTE. The second algorithm is deterministic and can estimate and track the direction of arrival of the signal. Then, it selects the mode which has the best gain in this direction in order to improve the link budget.

Les antennes à pointage électronique présentent des avantages significatifs dans les systèmes de communication sans fil. Malgré cela elles ne sont toujours pas implantées dans l'industrie automobile. En effet, l'espace limité et le toit en grande partie métallique freinent l’utilisation de ces aériens dans ce contexte contraint. De nombreux défis restent à relever pour concevoir un système efficace, peu encombrant, faible coût et permettant de rayonner sur 360°. L’objectif de cette thèse est donc la mise au point d’une antenne à balayage électronique pour application automobile fonctionnant dans la bande LTE. Un système de «type MIMO » est proposé. Une antenne à résonateur diélectrique efficace, multi-bandes et efficace est conçue selon une procédure de développement spécifique. Un déphaseur accordable est également mis au point et réalisé. Il utilise des commutateurs et un condensateur variable. Un déphasage de 360 degrés est obtenu, le dispositif est commandé électriquement. L’antenne et le déphaseur sont ensuite associés dans un système complet fonctionnant dans la bande LTE. Celui-ci utilise deux antennes identiques, une seule étant alimentée. Ce système complet est mesuré seul et sur le véhicule. Les résultats obtenus sont prometteurs et permettent d’envisager, moyennant quelques améliorations, une exploitation industrielle. Les études menées pour aboutir à ce dispositif sont détaillées dans le manuscrit. / Even though beam steering technology has significant advantages in wireless communication systems, it is still not implemented in the automotive industry. Indeed, the limited space and the large metal sheet on the rooftop are the challenges for such system. This thesis is focused on the design of the LTE beam steering antenna based on a MIMO system for an automotive environment. An appropriate multiband, efficient and compact Dielectric Resonator Antenna is conceived using a specific development procedure. Also, a tunable phase shifter is designed and realized with switches and a variable capacitor. It has 360 degrees phase shift and can be electrically controlled. The proposed DRA and phase shifter are integrated in a global antenna system for automotive application in the LTE band. We finally propose a MIMO system with an active beam steering radiation pattern. It is very compact and can be implemented on the vehicle rooftop. Using the proposed phase shifter, a beam steering antenna is obtained with a global coverage close to 360� for the antenna alone or on the vehicle. Measurements are made in the using context of the antenna. Finally, the developed system is, with some improvement, powerful for powerful enough for "commercial" automotive applications. The studies carried out to develop this antenna are detailed in this manuscript.