This thesis introduces low-cost implementations for the next generation distributed antenna system (DAS) using analogue radio over fibre. A multiple-input-multiple-output (MIMO) enabled radio over fibre (RoF) system using double sideband (DSB) frequency translation system is proposed. In such a system, the 2x2 MIMO signals can be transmitted to the remote antenna units (RAUs) from the base station via a single optical link. By using the DSB frequency translation, the original single-input-single-output (SISO) DAS can be upgraded into the MIMO DAS without implementing parallel optical links. Experimentally, the DSB frequency translation 2x2 MIMO RoF system transmits 2x2 LTE MIMO signals with 20MHz bandwidth in each channel via a 300m MMF link. The condition number of the system is < 10dB within the power equaliser bandwidth which means the MIMO system is well-conditioned and the crosstalk between the channels can be compensated by the MIMO signal processing. To install the DSB frequency translation system in a wideband service-agnostic DAS, the original MIMO signals need to be translated into unoccupied frequency bands over the DAS, which are usually occupied by specific applications that are not to be transmitted over the DAS. The frequency spectrum allocation of the wireless services is analysed showing that by choosing a particular LO frequency (2.2GHz in the UK), in the DSB frequency translation system, the original MIMO signals can always be translated into unoccupied frequency bands so that the same infrastructure can support multiple services. The idea of DSB frequency translation system can not only support MIMO radio over fibre but can also improve the SFDR of a general radio over fibre system. Because when the upper sideband and the lower sideband of the signal after translation are converted back to the original frequency band, the noise adds incoherently but the signals add-up coherently, this gives the system theoretically 2dB 3rd order SFDR improvement. If the idea of the DSB frequency translation is extended into a higher number of sidebands, the system SFDR can be further improved. Experimentally, the system 3rd order SFDR can be improved beyond the intrinsic optical link by 2.7dB by using quadruple sideband (QSB) frequency translation. It means the optical bandwidth in a general RoF system can be traded for the electrical SFDR. By integrating the analogue and the digital RoF systems, a hybrid DAS has been demonstrated, showing that the EVM dynamic range for the 4G LTE service (using digital RoF link) can be improved to be similar to the 3G UMTS service (using analogue RoF link), so that fewer number of RAUs for the LTE services are needed.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24232号 / 工博第5060号 / 新制||工||1790(附属図書館) / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 篠原 真毅, 教授 小嶋 浩嗣, 教授 山本 衛 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

La presente tesis consiste en el diseño de un sistema MIMO mediante la tecnología DAS (Distributed Antenna System), orientada a una red RF Indoor en la estación central del metropolitano, mejorando la cobertura de señal de los sistemas 2G, 3G y 4G. La tesis se ha organizado de la siguiente forma: En el primer capítulo se presenta el planteamiento del estudio de investigación, identificando las problemáticas existentes, trazando objetivos a lograr al final de la tesis. Parte importante de este capítulo es la justificación del estudio y su importancia que posee, así también identificar las variables, para finalmente tener un claro concepto de la problemática. En el segundo capítulo se presenta el marco teórico. Primero se describe los antecedentes del estudio de investigación relacionadas a las estaciones macro y sistemas Indoor que se ven involucrados en la estación central del metropolitano, así también la descripción de las bases teóricas vinculadas al problema, se elaboró un glosario de los términos que a la comprensión de la tesis. En el tercer capítulo se muestra el diseño metodológico, teniendo claro el tipo de investigación que será realizado, así mismo la operacionalización de las variables, que son segmentadas para poder ser medidas y/o controladas, por último la técnica de investigación a realizar. En el cuarto capítulo se muestra el cronograma de trabajo, aspectos económicos como presupuestos y financiamientos en base a los recursos a utilizar en el estudio. En el quinto capítulo se muestran las mediciones actuales de los parámetros de cobertura móvil en la estación central del Metropolitano. El sexto capítulo presenta las conclusiones y observaciones de la presente tesis. This thesis is about the design of a system MIMO using technology DAS (Distributed Antenna System), oriented to an RF Indoor network in the metropolitan central station, improving signal coverage of 2G, 3G and 4G systems. The thesis is organized as follows: In the first chapter, the approach of the research study was made identifying existing problems, tracing objectives to be achieved at the end of the thesis. An important part of this chapter is the justification of the study and its importance that it has, this we help us to identify variables to finally have a clear understanding of the problem. The second chapter presents the theoretical framework. First the background of the research study related to macro-stations and Indoor systems that are involved in the metropolitan central station and also the description of the theoretical basis related to the problem, a glossary of terms was made that support us to the understanding of the thesis. In the third chapter the methodological design is shown, knowing clearly the type of research to be done, likewise the operationalization of the variables, which are separated with the objective of be measured or controlled. Lastly, investigative technique to perform is shown. In the fourth chapter, we show the work schedule, budget and economic issues such as financing based on the resources used in the study sample. In the fifth chapter we show the current measurements of the parameters of mobile coverage in the metropolitan central station. The sixth chapter presents the conclusions and observations of this thesis.

Increasing energy consumption is a result of the rapid growth in cellular communication technologies and a massive increase in the number of mobile terminals (MTs) and communication sites. In cellular communication networks, energy efficiency (EE) and spectral efficiency (SE) are two of the most important criteria employed to evaluate the performance of networks. A compromise between these two conflicting criteria is therefore required, in order to achieve the best cellular network performance. Fractional frequency reuse (FFR), classed as either strict FFR or soft frequency reuse (SFR), is an intercell interference coordination (ICIC) technique applied to manage interference when more spectrum is used, and to enhance the EE. A conventional cellular model's downlink is designed as a reference in the presence of inter-cell interference (ICI) and a general fading environment. Energy-efficient cellular models,such as cell zooming, cooperative BSs and relaying models are designed, analysed and compared with the reference model, in order to reduce network energy consumption without degrading the SE. New mathematical models are derived herein to design a distributed antenna system (DAS), in order to enhance the system's EE and SE. DAS is designed in the presence of ICI and composite fading and shadowing with FFR. A coordinate multi-point (CoMP) technique is applied, using maximum ratio transmission (MRT) to serve the mobile terminal (MT), with all distributed antenna elements (DAEs), transmit antenna selection (TAS) being applied to select the best DAE and general selection combining (GSC) being applied to select more than one DAE. Furthermore, a Cloud radio access network (C-RAN) is designed and analysed with two different schemes, using the high-power node (HPN) and a remote radio head (RRH), in order to improve the EE and SE of the system. Finally, a trade-off between the two conflicting criteria, EE and SE, is handled carefully in this thesis, in order to ensure a green cellular communication network.