LiFi for automotive applications

Estudio del desempeño de sistemas de comunicaciones en semáforos en ciudades inteligentes mediante Li-Fi

ABSTRACT: Currently new alternatives in the frequency spectrum have been explored, obtaining a serie of immediate solutions in the frequencies belonging to the visible range (380-750 Hz). The Light-Fidelity(LiFi) technology arises as a result of the depletion of radio frequencies (RF) for communications, this technology is currently used for indoor and outdoor, having in both sectors a large number of applications. The thesis presented here proposes the study of a road junction. This road junction, con- tains a traffic light that serve as a server, which is assumed in a LiFi communication environment with the vehicles; all the elements described are designed specifically for a Smart City. The behavior of the road junction is modeled by a Markovian process, obtaining a conti- nuous Markov chain from the system. The Markov chain is numerically solved, applying the Queueing Theory with an M / M / 1 system in order to achieve the average queue length. Little’s theorem was applied to calculate the average delay. Besides, the mathematical expression of the data throughput through the average length of the queue is proposed, taking into account the average delay of the queue, the trans- mission speed and packet sizes in the transmitions. Additionally, general experiments for Visible Light Communications (VLC) are presen- ted; a encoder-decoder that modulates the information with a disk that interrupts the polarized rays of light between transmitter-receiver and a sound system that works with visible light, processing the energy with transducers that allow to change the transmission medium across the system. This work is structured in seven main chapters. The first chapter is an outline of the origins of optical technologies and smart cities, the second chapter presents the current work related to these two topics and its contribution in vehicular networks, having LiFi as optical technology. This chapter details the properties, characteristics and operating principles of LiFi technology. The general purpose experiments (described in previous pa- ragraphs) are shown in the third chapter. The Poisson processes, Markov chains, queuing theory, Little theorem and the IEEE 802.15.7 protocol specifications are approached in the fourth chapter to provide to the reader the necessary theory to understand the chap- ters of development and analysis of results (chapters fifth and sixth respectively). In these two chapters will be detailed the general system, the deduced Markov chain and the pa- rameters obtained from its solution. The seventh chapter presents the conclusions of the study, the contributions and the fu- ture work of the system and LiFi technology. At the end of the work, the program of the numerical solution of the Markov chain and the user manual of the graphical interface of downloading data in the system are attached.