THROUGHPUT OPTIMIZATION AND ENERGY ENHANCEMENT IN MASSIVE MIMO SYSTEMS

For the last few decades mobile technologies have undergone enormous transformation. Mobile broadband for cellular networks has been exponentially evolving with time and in order to meet the future expectation for this high demand newer and better technologies have to be invented. The enormous success of smart electronics such as tablets, smart phones and other hand held devices that use the Internet have generated a lot of Internet traffic therefore, diving LTE to its limit. LTE (4G) which is a high speed wireless communication standard for mobile phones and data terminals is a significant upgrade of GSM and UMTS network technologies. The Technology has downlink peak rates of 300Mbits/s and Uplink peak rates of 75Mbits/s with transfer latency rate of less than 5ms. Power Consumption level for LTE is of significant concern as well as the energy consumption in cellular networks. To solve the limitations in LTE, one great candidate is 5G radio standard. 5G relies heavily on massive MIMO to achieve its targets. This thesis looked into significance of Multi-antenna (Massive MIMO) at the BS as a solution for energy efficiency, increased data rates and the reduction of latency rates in wireless broadband communication. And the simulation results proved that Massive MIMO has better performance compared to conventional MIMO.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

3D multiple description coding for error resilience over wireless networks

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Mobile communications has gained a growing interest from both customers and service providers alike in the last 1-2 decades. Visual information is used in many application domains such as remote health care, video –on demand, broadcasting, video surveillance etc. In order to enhance the visual effects of digital video content, the depth perception needs to be provided with the actual visual content. 3D video has earned a significant interest from the research community in recent years, due to the tremendous impact it leaves on viewers and its enhancement of the user’s quality of experience (QoE). In the near future, 3D video is likely to be used in most video applications, as it offers a greater sense of immersion and perceptual experience. When 3D video is compressed and transmitted over error prone channels, the associated packet loss leads to visual quality degradation. When a picture is lost or corrupted so severely that the concealment result is not acceptable, the receiver typically pauses video playback and waits for the next INTRA picture to resume decoding. Error propagation caused by employing predictive coding may degrade the video quality severely. There are several ways used to mitigate the effects of such transmission errors. One widely used technique in International Video Coding Standards is error resilience. The motivation behind this research work is that, existing schemes for 2D colour video compression such as MPEG, JPEG and H.263 cannot be applied to 3D video content. 3D video signals contain depth as well as colour information and are bandwidth demanding, as they require the transmission of multiple high-bandwidth 3D video streams. On the other hand, the capacity of wireless channels is limited and wireless links are prone to various types of errors caused by noise, interference, fading, handoff, error burst and network congestion. Given the maximum bit rate budget to represent the 3D scene, optimal bit-rate allocation between texture and depth information rendering distortion/losses should be minimised. To mitigate the effect of these errors on the perceptual 3D video quality, error resilience video coding needs to be investigated further to offer better quality of experience (QoE) to end users. This research work aims at enhancing the error resilience capability of compressed 3D video, when transmitted over mobile channels, using Multiple Description Coding (MDC) in order to improve better user’s quality of experience (QoE). Furthermore, this thesis examines the sensitivity of the human visual system (HVS) when employed to view 3D video scenes. The approach used in this study is to use subjective testing in order to rate people’s perception of 3D video under error free and error prone conditions through the use of a carefully designed bespoke questionnaire.Petroleum Technology Development Fund (PTDF

Redes de nova geração e o serviço universal de telecomunicações em Portugal

Doutoramento em Engenharia EletrónicaThis thesis addresses the issue of Universal Service for telecommunications in the context of the access networks of next generation. This work aims to contribute to the redefinition of the concept of universal telecommunications service focusing primarily on extending it to broadband services as economic and social development factor and taking into account the degree of dependence that currently, modern societies have for the different communication and information services. Complementarily it also intended to meet some of the challenges set out in the European 2020 agenda. Universal Service is defined here as access to a telecommunications network (with obligations in terms of type and quality of service for the operator), by of all citizens at any country's geographical location, with uniform and accessible price. The approach adopted is the State as a mentor for social equity, respectful of the liberalized market dynamics but also knowledgeable of the requirements of modern telecommunications services and its relationship with the different technologies available. The possibility of subsidizing is assumed. The Universal Service´s provision is subject to open to all operators, which are assumed to possess other profitability businesses, than the Universal Service, using technologies similar to those prescribed for the respective Universal Service provision contest. Although the work has components of economic and financial analysis, the approach is the engineering point of view, looking for help to identify technical and organizational solutions which offer prospects for the dissemination and adoption of next generation network solutions. As a point of departure the work gives an overview on the state of the art access networks , trying to identify which of the differences between this reality and possible scenarios for next-generation network with potential access to the generality of the people . The case of the Portuguese reality will be given special attention, taking into account their specific characteristics in terms of geography, demography, economics and market dynamics. The main results of this work are: • Identification of possible scenarios for the evolution of existing networks, in particular in areas with deficit coverage. • Identification of possible operating models and business to the materialization of the above scenarios developed and its economic analysis in an attempt to determine the critical factors associated with sustainability and / or need for subsidies. • Contribution to the regulatory framework of new generation networks from the point of view of the constraints of technology and the specifics of the Universal Service.Esta tese aborda a questão do serviço universal de telecomunicações no contexto das redes de acesso de nova geração. Este trabalho pretende contribuir para a redefinição do conceito de Serviço Universal de Telecomunicações concentrando-se principalmente em estendê-lo a serviços de banda larga como factor de desenvolvimento económico e social e tendo em conta o grau de dependência que, actualmente, as sociedades modernas têm em relação aos diferentes serviços de comunicação e informação. De forma complementar pretende-se também ir ao encontro de alguns dos desafios enunciados na Agenda Europeia 2020. Serviço Universal é aqui definido como o acesso a uma rede de telecomunicações (com obrigações em termos de tipo e qualidade de serviço para o operador), por parte de todos os cidadãos, em qualquer localização geográfica do país, a preços uniformes e acessíveis. A perspectiva adoptada é a Estatal como mentor da equidade social, respeitador das dinâmicas de mercado liberalizado mas também conhecedor dos requisitos dos modernos serviços de telecomunicações e da sua relação com as diferentes tecnologias disponíveis. A possibilidade de subsidiação é assumida. A prestação de Serviço Universal é sujeita a concurso aberto a todos os operadores, que se assume possuírem outros negócios, que não apenas o Serviço Universal, com rentabilidade e usando tecnologias semelhantes às preconizadas para a respectiva prestação de Serviço Universal. Embora o trabalho desenvolvido tenha componentes de análise económico-financeira, a abordagem utilizada é a de engenharia, procurando contribuir para a identificação de soluções técnicas e organizacionais que possam oferecer perspectivas sustentáveis para a disseminação e adopção das soluções redes de nova geração. Como ponto de partida o trabalho apresenta uma visão geral sobre o estado da arte das redes de acesso, procurando identificar quais os diferenciais existentes entre essa realidade e a de possíveis cenários de rede de próxima geração com potencial de acesso para a generalidade dos cidadãos. O caso da realidade Portuguesa será objecto de uma atenção especial, tendo em consideração as suas especificidades em termos de geografia, demografia, economia e dinâmicas do mercado. Os principais resultados deste trabalho são os seguintes: • Identificação de possíveis cenários para a evolução das redes actuais, nomeadamente em áreas com deficit de cobertura de rede. • Identificação de possíveis modelos de operação e negócio para a materialização dos cenários acima desenvolvidos e respectiva análise económica, como tentativa de determinar os factores críticos associados à sua sustentabilidade e /ou necessidade de subsidiação. • Contributo para o quadro regulatório das Redes de Nova Geração sob o ponto de vista dos constrangimentos das tecnologias e das especificidades do Serviço Universal

Optimization of Mobility Parameters using Fuzzy Logic and Reinforcement Learning in Self-Organizing Networks

In this thesis, several optimization techniques for next-generation wireless networks are proposed to solve different problems in the field of Self-Organizing Networks and heterogeneous networks. The common basis of these problems is that network parameters are automatically tuned to deal with the specific problem. As the set of network parameters is extremely large, this work mainly focuses on parameters involved in mobility management. In addition, the proposed self-tuning schemes are based on Fuzzy Logic Controllers (FLC), whose potential lies in the capability to express the knowledge in a similar way to the human perception and reasoning. In addition, in those cases in which a mathematical approach has been required to optimize the behavior of the FLC, the selected solution has been Reinforcement Learning, since this methodology is especially appropriate for learning from interaction, which becomes essential in complex systems such as wireless networks. Taking this into account, firstly, a new Mobility Load Balancing (MLB) scheme is proposed to solve persistent congestion problems in next-generation wireless networks, in particular, due to an uneven spatial traffic distribution, which typically leads to an inefficient usage of resources. A key feature of the proposed algorithm is that not only the parameters are optimized, but also the parameter tuning strategy. Secondly, a novel MLB algorithm for enterprise femtocells scenarios is proposed. Such scenarios are characterized by the lack of a thorough deployment of these low-cost nodes, meaning that a more efficient use of radio resources can be achieved by applying effective MLB schemes. As in the previous problem, the optimization of the self-tuning process is also studied in this case. Thirdly, a new self-tuning algorithm for Mobility Robustness Optimization (MRO) is proposed. This study includes the impact of context factors such as the system load and user speed, as well as a proposal for coordination between the designed MLB and MRO functions. Fourthly, a novel self-tuning algorithm for Traffic Steering (TS) in heterogeneous networks is proposed. The main features of the proposed algorithm are the flexibility to support different operator policies and the adaptation capability to network variations. Finally, with the aim of validating the proposed techniques, a dynamic system-level simulator for Long-Term Evolution (LTE) networks has been designed

A novel approach to emergency management of wireless telecommunication system

The survivability concerns the service continuity when the components of a system are damaged. This concept is especially useful in the emergency management of the system, as often emergencies involve accidents or incident disasters which more or less damage the system. The overall objective of this thesis study is to develop a quantitative management approach to the emergency management of a wireless cellular telecommunication system in light of its service continuity in emergency situations – namely the survivability of the system. A particular wireless cellular telecommunication system, WCDMA, is taken as an example to ground this research.The thesis proposes an ontology-based paradigm for service management such that the management system contains three models: (1) the work domain model, (2) the dynamic model, and (3) the reconfiguration model. A powerful work domain modeling tool called Function-Behavior-Structure (FBS) is employed for developing the work domain model of the WCDMA system. Petri-Net theory, as well as its formalization, is applied to develop the dynamic model of the WCDMA system. A concept in engineering design called the general and specific function concept is applied to develop a new approach to system reconfiguration for the high survivability of the system. These models are implemented along with a user-interface which can be used by emergency management personnel. A demonstration of the effectiveness of this study approach is included.There are a couple of contributions with this thesis study. First, the proposed approach can be added to contemporary telecommunication management systems. Second, the Petri Net model of the WCDMA system is more comprehensive than any dynamic model of the telecommunication systems in literature. Furthermore, this model can be extended to any other telecommunication system. Third, the proposed system reconfiguration approach, based on the general and specific function concept, offers a unique way for the survivability of any service provider system.In conclusion, the ontology-based paradigm for a service system management provides a total solution to service continuity as well as its emergency management. This paradigm makes the complex mathematical modeling of the system transparent to the manager or managerial personnel and provides a feasible scenario of the human-in-the-loop management

Radio network management in cognitive LTE-Femtocell Systems

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London.There is a strong uptake of femtocell deployment as small cell application platforms in the upcoming LTE networks. In such two-tier networks of LTEfemtocell base stations, a large portion of the assigned spectrum is used sporadically leading to underutilisation of valuable frequency resources. Novel spectrum access techniques are necessary to solve these current spectrum inefficiency problems. Therefore, spectrum management solutions should have the features to improve spectrum access in both temporal and spatial manner. Cognitive Radio (CR) with the Dynamic Spectrum Access (DSA) is considered to be the key technology in this research in order to increase the spectrum efficiency. This is an effective solution to allow a group of Secondary Users (SUs) to share the radio spectrum initially allocated to the Primary User (PUs) at no interference. The core aim of this thesis is to develop new cognitive LTE-femtocell systems that offer a 4G vision, to facilitate the radio network management in order to increase the network capacity and further improve spectrum access probabilities. In this thesis, a new spectrum management model for cognitive radio networks is considered to enable a seamless integration of multi-access technology with existing networks. This involves the design of efficient resource allocation algorithms that are able to respond to the rapid changes in the dynamic wireless environment and primary users activities. Throughout this thesis a variety of network upgraded functions are developed using application simulation scenarios. Therefore, the proposed algorithms, mechanisms, methods, and system models are not restricted in the considered networks, but rather have a wider applicability to be used in other technologies. This thesis mainly investigates three aspects of research issues relating to the efficient management of cognitive networks: First, novel spectrum resource management modules are proposed to maximise the spectrum access by rapidly detecting the available transmission opportunities. Secondly, a developed pilot power controlling algorithm is introduced to minimise the power consumption by considering mobile position and application requirements. Also, there is investigation on the impact of deploying different numbers of femtocell base stations in LTE domain to identify the optimum cell size for future networks. Finally, a novel call admission control mechanism for mobility management is proposed to support seamless handover between LTE and femtocell domains. This is performed by assigning high speed mobile users to the LTE system to avoid unnecessary handovers. The proposed solutions were examined by simulation and numerical analysis to show the strength of cognitive femtocell deployment for the required applications. The results show that the new system design based on cognitive radio configuration enable an efficient resource management in terms of spectrum allocation, adaptive pilot power control, and mobile handover. The proposed framework and algorithms offer a novel spectrum management for self organised LTE-femtocell architecture. Eventually, this research shows that certain architectures fulfilling spectrum management requirements are implementable in practice and display good performance in dynamic wireless environments which recommends the consideration of CR systems in LTE and femtocell networks