M. Tech. Electrical Engineering. / Discusses how to find the best set of base station locations in 3G networks that cover a given number of mobile users with a good quality signal at optimal cost, using Genetic algorithms. The selected approach must alleviate the inefficiencies introduced traditional planning approaches.

Η μεταφορά και διάδοση πληροφορίας με ασύρματο τρόπο είναι ένα επιστημονικό πεδίο που τις τελευταίες δεκαετίες γνωρίζει ιδιαίτερη άνθιση, καθώς μας απαλλάσσει από τις πολλές περιττές καλωδιώσεις των ενσύρματων δικτύων και δίνει τη δυνατότητα ευρείας κάλυψης χρηστών, που μπορούν κατά τη διάρκεια της μεταφοράς πληροφορίας να κινούνται. Συγκεκριμένα, ο κλάδος των κινητών τηλεπικοινωνιών, εξετάζει την επικοινωνία χρηστών μεταξύ τους με ασύρματο τρόπο, μέσω συσκευών κινητής τηλεφωνίας (ME-mobile equipment) οι οποίες δεν είναι παρά μικρές κεραίες ενσωματωμένες σε συσκευές με μνήμη και λογισμικό. Η μελέτη και η συνεχής βελτιστοποίηση των συστημάτων κινητών επικοινωνιών,αποτελεί το μεγάλο και διαρκές στοίχημα των τηλεπικοινωνιακών μηχανικών. Η ανάπτυξη όλο και αποδοτικότερων συστημάτων είναι αναγκαία, έτσι ώστε να μπορούμε να εκμεταλλευτούμε κατά το δυνατόν καλύτερα το περιορισμένο διαθέσιμο φάσμα, ελαχιστοποιώντας τις παρεμβολές, βελτιστοποιώντας την ποιότητα παροχής υπηρεσιών, με παράλληλη αύξηση του αριθμού των εξυπηρετούμενων χρηστών, με απώτερο σκοπό να καταλήξουμε σε ένα βέλτιστο μοντέλο σχεδίασης. Η παρούσα διπλωματική εξετάζει τις παραμέτρους οι οποίες λαμβάνονται υπόψιν στη σχεδίαση ενός συστήματος κινητών επικοινωνιών, τα μοντέλα που χρησιμοποιούνται για την εκτίμηση των απωλειών λόγω των ιδιαιτεροτήτων της περιοχής διάδοσης και της ύπαρξης ραδιοσκιάς και διαλείψεων και επιχειρεί να εφαρμόσει ένα απλοποιημένο μοντέλο ραδιοκάλυψης στην ηπειρωτική περιοχή της περιφέρειας Αττικής. / During the last decades, wireless propagation and transmission of data, is a scientific field which grows up rapidly, due to several major advantages of wireless telecommunications, such as the lack of wired connections and the opportunity to provide telecommunication services to users who are not static. Specifically, the field of mobile telecommunications, examines communication between users who are possibly moving, through mobile equipment which consists of an antenna, software and memory. The continuous optimization of mobile telecommunication's systems is an enduring bet for telecommunication engineers. The development of increasingly efficient systems is needed so that we can exploit in the best way our limited available spectrum, while at the same time we are trying to fulfill three other major targets: minimize interference, optimize quality of service, increase the number of served users, with a view to arrive at an optimal design model. This thesis examines the structure of a mobile telecommunication's system, the factors taken into account in the design of a mobile system and the models used to estimate losses due to the peculiarities of the region, the existence of shadowing and multipath fading. Having mentioned the whole methodology behind cell planning and the way that a mobile system is structured, we are finally applying a simplified model of radio coverage in the area of Attica.

[pt] A quantização eficiente dos coeficientes do filtro de síntese utilizado em codificadores de voz CELP (Code Excited Linear Prediction) é fundamental para o bom desempenho desta classe de codificadores, especialmente quando se considera a operação em taxas inferiores a 8 Kbps. Neste trabalho são examinados três quantizadores vetoriais distintos que apresentam bom potencial para utilização em codificadores que operem a baixas taxas de bits. Cada um desses quantizadores foi implementado dentro da estrutura do codificador VSELP (Vector Sum Excited Linear Prediction) uma variação importante do codificador CELP padronizada para uso na telefonia celular digital americana. Estas três técnicas de quantização vetorial dos coeficientes do filtro baseiam-se na representação LSP e são comparadas em termos da robustez aos erros no canal de transmissão, da complexidade computacional de implementação e, principalmente, da qualidade da voz sintetizada (avaliada em função de medidas objetivas de razão sinal ruído ponderada e de testes de escuta informais). Também é examinada a aplicação da técnica de Simulated Annealing para associação de índices aos níveis de saída dos quantizadores, visando diminuir a sua sensibilidade aos erros no canal de transmissão. / [en] Efficent quantization of synthesis filter coefficients on CELP (Code Excited Linear Prediction) coders is very important for a good performance of this class of coders, specially when operating below 8 Kbps. Three vector quantizers with good potential for utilization on low rate coders are studied. Each of them was implemented inside the structure of VSELP( Vector Sum Linear Prediction) coder, an important menber in the class of CELP coders: VSELP is the north American cellular Communication standard. These three vector quantizers work with LSP parameters and are compared considering the robustness to channel errors, complexity and quality of sythesized speech. The quality of synthesized speech is evaluated considering objective measures of frequency weighted signal to noise ratio and subjective results obtained from informal listening tests. In order to improve the robustness to channel errors, the problem of binary indices assignment to the output levels of the quantizer is also investigated. The technique used to determine good indices assignments is Simulated Annealing

M.Phil. (Business Management) / The purpose of the research was to explicate business competitive challenges through increasing scientific knowledge relating to the effect of Value Chain on the Customer Experience within the South African Mobile Telecommunications industry. Operators display a tendency of commoditised competition, offering little differentiation that Customers value. The qualitative and time bound study analysed the perspective of sixteen interviewees, representing the full Value Chain from respective operators. Following the aim to understand the participants’ perception of how the Value Chain impacts Customer Experience, the Content Analysis method of analysis was utilised for the gathering of insights. Findings reflect a lack of maturity in the understanding of Customer Experience and Value Chain, and a resulting incapability to maximise the effect of the Value Chain on the Customer Experience. Notwithstanding, there exists an opportunity to apply a Value Chain perspective in order to improve the Customer Experience and enhance mutual value.

No / A method and apparatus are provided for ad hoc networking over a universal mobile telecommunications system (UMTS) . In the method, if user equipment (40A) (such as a mobile phone) is not within normal cell coverage (20) , then in an uplink procedure a message which would normally have not be able to be transmitted directly from the User Equipment (40A) to a Base Station (10) is instead forwarded towards the Base Station (10) via one or more intermediate User Equipments (40B) . In the method, the user equipment (40A) is arranged to synchronise itself with the Base Station (10) to acquire timeslot and frame synchronisations and thence perform probing activities to build up a list of neighbouring User Equipments. From this list and power and signal to interference calculations the user equipment (40A) is able to work out the relative positions of its neighbours with respect to the Base Station and itself and come to a routing decision for forwarding its message towards the Base Station.

Retaining high-value and profitable customers is a major strategic objective for many companies. In mature mobile phone markets where growth has slowed, the defection of customers from one network to another has intensified and is strongly fuelled by poor Customer Experience. Trends in the service economy suggest that experience can be exploited as a means of supplying the basis of a new economic offering, ignited in part by the shift that is taking place in the analysis of people’s interaction with digital products. In this light, the research describes a strategic approach to the use of Information Systems as a means of improving Customer Experience. Using Action Research in a mobile telecommunications operator, a Customer Experience Monitoring and Action Response model (CEMAR) is developed that evaluates disparate customer data, residing across many systems, builds experience profiles and suggests appropriate contextual actions where experience is poor. The model provides value in identifying issues, understanding them in the context of the overall Customer Experience (over time) and dealing with them appropriately. The novelty of the approach is the synthesis of data analysis with an enhanced understanding of Customer Experience which is developed implicitly, in real-time and in advance of any instigation by the customer.

[pt] O setor de telecomunicações móveis figura entre os mais dinâmicos e complexos ambientes de negócios. Indústrias de TIC (Tecnologia de Informação e Comunicações), antes separadas, começam a mesclar-se, pouco a pouco, dificultando a delimitação de fronteiras entre os participantes que, de competidores, em muitas situações, passam à condição de parceiros, com vistas à complementação de recursos e de competências. Esta pesquisa tem como objetivo a verificação da adequação da estratégia da Nokia Smart Devices à indústria de telefonia móvel, considerando suas alianças e a estratégia competitiva global. A investigação foi conduzida com o uso da metodologia de estudo de caso. Múltiplas fontes de evidência foram utilizadas para permitirem a convergência triangular dos dados. A interpretação e a análise dos dados foram realizadas com auxílio do referencial teórico identificado, e baseadas no Global Strategic Network Analysis – SNA – framework, de Macedo-Soares (2011). Os resultados da pesquisa apontam a presença de ameaças que desafiam a liderança de empresas, muitas vezes tidas como sólidas. O entendimento das implicações estratégicas dos fatores macroambientais (estruturais e relacionais) e dos fatores organizacionais é fundamental para a composição de uma estratégia consistente, capaz de alavancar as forças criadas pela organização ou pela rede, ou de minimizar as fraquezas, com o propósito de aproveitar as oportunidades oferecidas pelo ambiente, e, ainda, de mitigar as ameaças, na busca pela geração de vantagem competitiva. / [en] The mobile phone sector is among the most dynamic and complex business environment. ICT (Information and Communication Technology) industries, which were, to date, treated in a separated way, gradually start to converge, so that the boundaries among the participants thereof become hardly identifiable. In some cases, the members undertake the role of competitors and, in other occasions, they act as strategic partners, aiming at the complementation of resources and competencies. The present research intends to verify the adequacy of Nokia Smart Devices strategy to the Mobile Phone industry, considering its alliances and the global competitive strategy. The work adopted the case study methodology. For the collection of the required data, multiple sources and means to were used in accordance with the strategy of data and method triangulation, so as to ensure results consistency. Data interpretation and analysis were carried out in the light of the research s theoretical references and pursuant to the Global Strategic Network Analysis – SNA framework, by Macedo-Soares (2011). The results point out the presence of threats that challenge companies leadership which may sometimes be considered as very solid organizations. The correct comprehension of strategic implications of macroenvironmental (structural and relational) and organizational factors is fundamental to a correct and consistent strategy composition, that may leverage the strengths generated by the organization and its network, or even minimize the weaknesses, in order to benefit from opportunities offered by the sector while and to mitigate the threats there from, while reaching a competitive edge.

O setor de telecomunicações, mundial e brasileiro, vive um momento de pressão por rentabilidade e competitividade das empresas. Adicionalmente, a variedade de soluções tecnológicas traz incertezas quanto à adoção dos usuários às novas tecnologias e à identificação e implantação de modelos de negócios sustentáveis. Esta pressão por competitividade leva as operadoras a adotarem uma atitude de liderança perante a inovação, objetivando a diferenciação e manutenção das margens. Um dos elementos diferenciadores das operadoras móveis está situado na inovação decorrente da convergência digital, entre as tecnologias de redes de comunicação, de processamento e de apresentação das informações. Apesar da convergência digital existir tecnologicamente desde a década de 60 com o advento do protocolo TCP/IP, é atualmente que se observa o surgimento de novos modelos de negócios e de produtos e serviços convergentes, baseados em novos atributos de valor fornecidos ao consumidor final. Nesta conjuntura de elevada competitividade e incerteza, julga-se relevante que as iniciativas estratégicas relativa à inovação sejam adequadamente geridas, especificamente aquelas referentes à convergência digital, para que se tornem elementos diferenciadores e sustentadores da competitividade empresarial. A pesquisa em questão visa identificar e analisar os impactos na gestão estratégica orientada à inovação, decorrente da convergência digital entre tecnologias de processamento de dados (informática) e redes de transmissão de voz e dados (telecomunicações), limitados à telefonia móvel brasileira. Neste trabalho utiliza-se o conceito amplo de Tecnologia da Informação (TI) atribuído por Porter e Millar (1987), onde TI inclui os sistemas de informação, o uso de hardware e software, telecomunicações, automação e recursos multimídia para o tratamento e uso de dados, informações e conhecimento. O método de pesquisa adotado é estudo de caso, a fim de construir um roteiro de investigação e análise, e identificar possíveis ajustes ou complementos ao campo teórico da gestão estratégia, a partir das experiências das operadoras móveis brasileiras. Através do método de pesquisa escolhido, objetiva-se responder as seguintes perguntas: Por que a convergência digital entre telecomunicações e informática traz implicações à gestão estratégica orientada à inovação na telefonia móvel? Existem características preponderantes ou específicas na convergência digital entre telecomunicações e informática na telefonia móvel, que justifiquem mudanças no campo teórico da gestão estratégica e da gestão tecnológica orientada à inovação? Como devem ser tratados os modelos de gestão estratégica nas organizações de telecomunicações, perante a convergência digital entre telecomunicações e informática? Para identificação de complementos ao campo teórico, são selecionadas três operadoras móveis brasileiras, empresas relevantes e com posicionamentos distintos perante a convergência digital e ao sistema de valor convergente entre telecomunicações e informática. Os principais resultados alcançados no estudo realizado são: a proposta de um complemento ao modelo da convergência digital proposto por Fransman (2001), a fim de capturar aspectos dinâmicos da competição e colaboração entre os setores econômicos implicados, diferenciando-os pelos tipos de convergência digital; a identificação de uma trajetória comum às operadoras móveis brasileiras frente a convergência digital. Finalmente, considera-se esta pesquisa relevante. Pois as operadoras móveis brasileiras têm uma atitude de liderança na adoção e disseminação da inovação decorrente da convergência digital, e seus modelos e práticas de gestão são tratados tradicionalmente como investimentos em P&D ou em inovação de produtos e serviços. / Telecommunications industry faces fierce competition both locally and globally, in which innovation plays a significant role for companies competitiveness and prosperity. In addition, a variety of technological solutions brings up uncertainty about users embracing to new technologies and about businesses models profitability. One element that enables mobile operators to differentiate is the innovation triggered by digital convergence of the following technologies: information processing, distribution and presentation. Though digital convergence appeared in the sixties with TCP/IP protocol, in fact, it is nowadays that new convergent products or services are available to end customers. Under these circumstances of fierce competition and uncertainties, it is relevant that strategic initiatives become properly managed, specifically the ones related to innovation based on digital convergence, in order to enable sustainable competitive advantage. This research aims to identify and analyze implications of digital convergence between telecommunications and IT toward strategic management, specifically in Brazilian mobile industry. In this project IT is applied within a broad concept proposed by Porter and Millar (1987), in which it encompasses information systems, hardware/software, telecommunications, automation, multi-media resources to treat and use data, information and knowledge. Case study is the method chosen. Brazilian mobile operators are investigated in order to build a framework for assessing the impacts of digital convergence, and to identify potential adjustments or extensions to strategic management theory. This research intends to answer: Why does digital convergence between telecommunications and IT impact strategic management related to innovation in the mobile telecommunications industry? Are there any dominant or specific characteristics of digital convergence between telecommunications and IT in the mobile industry, which justify changes in strategic management or in innovation technology management theories? How should be treated strategic management models in telecommunications industry, to accommodate implications of digital convergence between telecommunications and IT? In order to accomplish the investigation, three relevant Brazilian mobile operators are chosen to participate on this research. Each company has a different position in the convergent value system between telecommunications and IT, and on the type of convergence focused. The main results achieved are: a proposed complement to Fransmans digital convergence model (2001), in order to capture the dynamic aspects of competition and collaboration within the convergent industries; an identification of a common trajectory among Brazilian mobile operators within the digital convergence business environment. This research project can be considered relevant. Due to the fact that Brazilian mobile operators take in one hand a lead attitude in disseminating innovations based on digital convergence; in the other hand a conventional attitude in managing it as R&D investments.

Mobile telecommunications industry has experienced high growth rates for the recent 30 years. Accordingly, forecasting the future of mobile telecommunications services is important not only for mobile operators but also for all stakeholders in this industry ranging from handset manufacturers to vendors. In this thesis, the diffusion of mobile telecommunications services in 20 countries from different regions around the world is examined for the period of 1981 to 2010 with special emphasis on Turkey, in order to address the uncertainty in optimal model selection. The Gompertz, logistic and Bass models are fitted to the observed data of mobile phone penetration by means of nonlinear least squares. The fitness accuracies of the models are evaluated based on root mean square error (RMSE). Empirical results show that S-shaped growth models are capable of explaining the diffusion of mobile telecommunications services. The findings also suggest that there is no superior model in defining the diffusion process and the most suitable model is country dependent. Finally, we observe that the diffusion in late entrant countries appears to be faster than pioneer countries and peak demands in mobile telephones occur during the period of 1999 to 2006, which suggests a remarkable multinational learning effect and significance of the transition into digital technology.

[pt] O objetivo desta dissertação é propor um sistema de mineração de dados completo para a solução de problemas de retenção de clientes, presentes nas mais variadas indústrias. Tal solução reside na correta identificação, em meio a gigantescas bases de dados, dos clientes cujos perfis e históricos de comportamento denotam que sua saída da empresa é iminente. Agindo então sobre a inteligência gerada a partir desta classificação de clientes, incentivos e ações de retenção devem ser postos em prática para evitar e/ou minimizar a perda para algum concorrente de clientes valiosos. Ao longo do processo de mineração de dados, deu-se atenção ao processo de preparação e representação dos dados e métodos de seleção de variáveis, na tentativa de melhorar e otimizar o desempenho dos modelos a serem estudados. Vários modelos diferentes foram testados, otimizados e comparados na tarefa de classificação de clientes como aqueles que permanecerão na empresa ou aqueles que apresentam riscos de abandono. Entre os modelos estudados estão: redes neurais, sistemas neuro-fuzzy hierárquicos, algoritmos genéticos, árvores de decisão e máquinas de vetor de suporte. Em particular, avaliou-se a questão do abandono de clientes (churn) na indústria de telecomunicações móvel brasileira, devido à disponibilidade de dados reais para a análise. Foi feito um estudo abrangente do problema do churn, identificando suas causas, conseqüências e detalhes. Conclui-se com uma análise do impacto da implementação da metodologia proposta em ações de retenção de clientes, sob o prisma da lucratividade ou corte de despesas em que tal utilização implicaria. / [en] The goal of this work is to propose a complete data mining system for the solution of customer retention problems, commonly found in many industries. Such a solution encompasses the accurate identification among huge amounts of data of those consumers who would most likely end their relationship with the firm, based on their historical behavior and individual profile. Acting upon the intelligence provided by a precise customer classification, incentives and retention actions should be put into practice to prevent or minimize the losses of valuable clients to competitors. Throughout the data mining process designed here, great care was given to the preparation and representation of the data and to input selection methods, in an effort to optimize the performance of the classification models. Various different classification techniques have been tested, with the objective of finding the one best suited for the task at hand: to pinpoint those customers who present clear risks of abandoning the analyzed company. Among the studied models were neural networks, decision trees, genetic algorithms, neuro-fuzzy systems and SVMs (Support Vector Machines). As a case study, the issue of churn (loss of customer to a competitor) in the Brazilian wireless telecommunications was tackled, due to the availability of data. A detailed study was made, identifying the causes, consequences and details of the business problem. As a conclusion, the great impact of the implementation of the proposed system in retention strategies of wireless carriers is evaluated, under the view of the profitability that would be generated by its use.