Realizado el acto de Defensa y Lectura de la Tesis el día de de 2017 en Pozuelo de Alarcón (Madrid). CALIFICACIÓN: EL PRESIDENTE LOS VOCALES EL SECRETARIO V Porque si hay un contrincante al que debes vencer en una carrera de larga distancia, ése no es otro que el tú de ayer. Haruki Murakami VII
AgradecimientosHa sido un camino largo, demasiado, con cambio de tema tras los primeros años, con la compatibilización con otros proyectos, con errores en las medidas, con obstáculos para las publicaciones, con desmotivaciones, pero como con todo en la vida, lo importante es alcanzar la meta y aprender por el camino. Así, quiero agradecer de corazón a todas las personas que, de una forma u otra, me han acompañado en este trayecto.A mis padres, por su apoyo continuo, por motivarme en los buenos y en los malos momentos, pero también por decirme lo que piensan aunque no vaya a gustarme. Y a mi hermano por estar ahí y verlo todo tan fácil.
XI
AbstractOver the last decade, white light emitting diodes (WLED) based luminaries have been exponentially replacing traditional lamps (incandescent, fluorescent), due to their long lifetime and low heat generation, but mainly because of their high energy efficiency. Visible Light Communication (VLC) is based on the dual use of LED lamps for illumination and information transmission, making use of the LED short switching times. Therefore, VLC is viewed as an alternative or complement to the traditional communication systems in home scenarios. Over the last years, many research efforts have been oriented to maximize the transmission rate of VLC systems, especially through the use of high spectral efficiency modulation techniques as OFDM. However, it has not been studied how the use of an LED lamp as a VLC emitter affects its main advantage as lighting technology, which is energy efficiency.In this thesis, it is assumed the following hypothesis: the waveform of the VLC modulation signal influences the energy efficiency of the LED luminaire, and specifically the energy performance of its control element or driver. LED lamp drivers are usually formed by switching power supplies which apply a constant current to the light source. Using a switched waveform modulation signal fits this principle. However, utilizing a continuous waveform modulation signal, as employed in modulation techniques as OFDM, modifies the current nature both in the light source (LED) and the driver, affecting their behaviour.The main goal of this thesis is to analyse how the waveform of the modulation signal affects the energy performance of the VLC driver. For that purpose, the work is divided into three steps: theoretical model; model validation through simulations and experiments; and results achievement. In order to analyse the driver energy efficiency, the quality factor "η", named driver Energy Efficiency Ratio is defined. "η" is the ratio between the power dissipated by the LED and the total dissipated power. At the theoretical model, the efficiency ratio of the VLC driver (and its LED and MOS elements XII individua...