4 research outputs found
Diseño e implementación de un sistema de transmisión NOMA en FPGA
No full text“En el presente trabajo se desarrolla un sistema de transmisión de dos señales distintas que utiliza el esquema de acceso multiusuario conocido como NOMA (NonOrthogonal Multiple Access), cuyo destino previsto es el uso en sistemas de telefonía celular. En este sistema se utiliza la estrategia de modulación digital QPSK, la cual permite realizar el proceso necesario para la aplicación del esquema NOMA, con el objetivo de obtener una sola señal que contenga la información de las señales originales sin pérdidas, corrupciones o interferencias entre sí. Un sistema de modulación QPSK se muestra en el presente trabajo y se simula en MATLAB, y se explican las consideraciones que se tuvieron para utilizarlo con el esquema de acceso NOMA. El sistema de transmisión NOMA se simula en MATLAB y se desarrolla en lenguaje VHDL para su implementación en FPGA, para lo cual primero se plantea un enlace de transmisión de una estación base en la que se genera información destinada a dos usuarios receptores. En la simulación computacional se muestra de manera gráfica lo que sucede con las señales generadas en la estación base al ser capturadas, digitalizadas, moduladas y finalmente integradas mediante el esquema de acceso NOMA, y su respuesta se utiliza como referencia para comprobar la respuesta del sistema implementado en el FPGA.
Evaluation of the Digital Data Performance Transmission on a Fiber-Radio System
No full textThis work shows a set of numerical simulations to evaluate the digital data performance transmission for a fiber-radio system. For this goal, VPI Photonics software is used to simulate the transmission of a digital signal at a bit rate of 2.4 GHz through an optical link of 25 km of single-mode standard fiber (SM-SF). Whereas MATLAB software is utilized to emulate a wireless channel considering four main phenomena inherent to this channel, such as multipath and slow fading, co-channel interference, and additive white Gaussian noise (AWGN). The modeling carried out in MATLAB considers a user in movement within its coverage area cell. The constellation diagram, bit error rate (BER), and signal-to-interference-plus-noise ratio (SINR) statistical tests are used to evaluate the performance of this approach. This proposal finds potential applications in the field of cellular telephony, the Internet of Things (IoT), or any other communication system to evaluate the quality of the delivered signal to a user in motion within a particular coverage cell
Implementation of a Multimode Optical Source in the VPIphotonics Software
No full textThis paper shows the design and implementation of a multimode optical source in the VPIphotonics software. Considering all the powerful features this software provides, the absence of a device such as a multimode source in its library constitutes a limitation for particular simulations. The use of single-mode optical sources available in the library allows for obtaining a multimode spectrum. The mathematical relationship that describes a multimode optical source is numerically evaluated in MATLAB. Afterward, this graphical result is compared with the obtained in the VPIphotonics software. The importance of using this type of optical source resides in its applications for modern optical communications systems, microwave photonic filters (MPFs), opto-electronic oscillators (OEOs), and sensors. This implementation aims to drive virtual systems where required, and by setting its parameters similar to the real ones, it allows good studying and understanding of system responses. Even more, it predicts or ensures the results of experimental systems by having the possibility to vary different parameters. A practical application of the obtained multimode optical spectrum is shown with its use in the implementation of an MPF. This last simulation is experimentally corroborated. This work presents a technique for designing a multimode optical source in this particular software and provides also academics and students, with a methodology for the use of this software for this kind of photonic design
Experimental Demonstration of Channel Routing of Microwave Signals Sharing an Optical Link by Using a Tunable Optical Band-Pass Filter
No full textThe imperative need to share an optical link to optimize its use among multiple users for data distribution continues to be a topic of technological challenge. In this regard, it is well known that one of the most common techniques is the WDM technology. However, this paper describes a technical alternative that enables channel routing for data sharing over an optical link between two users using a tunable Optical Band-Pass (OBP) filter. This proposal is experimentally validated. To demonstrate the viability of this approach, microwave signals are used as data. The selected microwave signal is wirelessly transmitted at the end of the optical link. The signal-to-noise ratio (SNR) parameter measure is adopted to evaluate the quality of each microwave signal, achieving an average SNR of 37.01dB. This proposal is validated for microwave signals within the S-band (2 to 4 GHz), however, this frequency interval can be expanded. Potentially, this approach allows the sharing of optical fiber among multiple users to deliver services via wireless links in indoor environments
