Weyl-Heisenberg Spaces for Robust Orthogonal Frequency Division Multiplexing

Design of Weyl-Heisenberg sets of waveforms for robust orthogonal frequency division multiplex- ing (OFDM) has been the subject of a considerable volume of work. In this paper, a complete parameterization of orthogonal Weyl-Heisenberg sets and their corresponding biorthogonal sets is given. Several examples of Weyl-Heisenberg sets designed using this parameterization are pre- sented, which in simulations show a high potential for enabling OFDM robust to frequency offset, timing mismatch, and narrow-band interference

Optical signal processing for efficient information networks

With the internet and rise of personal electronics there is an ever increasing amount of data collected and transmitted every day; modern communication systems will soon be overwhelmed. The driving force behind the demand is an increasing speed of signal acquisition, in the public domain, as well as medicine and industry; newer technologies allow massive amounts of data produced through text, voice, and video. This puts strain on both signal acquisition systems and communications systems to increase the total information flow. Transmission down fiber links is enabled by the large but limited bandwidth of optical fiber, and as we look toward the future, efficient use of the available optical bandwidth is paramount. I apply the large bandwidth of fiber and ultrafast speed of nonlinear optics to solve these problems, implementing high-speed and efficient signal acquisition and communication systems. With the increased volume of information being transferred, compression of data has become essential to allow multimedia communication. Data is acquired then compressed and transmitted, requiring massive computing power. Using the information theory technique coined “compressed sensing”, we demonstrate real time compression at signal acquisition, removing a timeconsuming and bandwidth inefficient step in a complete communication link. I use dispersion and nonlinear wave mixing in optical fiber, and gigahertz electro-optics to shape light at terahertz speeds, reaching towards the limit of compressed image acquisition. To complete a high-speed communications link, I investigate the use of Nyquist optical time division multiplexing to maximize spectral efficiency. The square spectral shape of a Nyquist pulse is ideal, but the pulse ripples on forever in the time domain, presenting problems for demultiplexing Nyquist signals at the receiver. I present a solution using coherent detection with a biorthogonal Nyquist pulse to eliminate interference from neighboring channels, and implement a proof of concept system using nonlinear wave mixing. Stable clock transfer is essential for coherent communication, but environmental fluctuations erode clock information, reducing the effective data rate of the communications channel. I present a versatile solution for stable time and frequency transfer using dispersion and nonlinear wave mixing in optical fiber

Esquema de transmisión de información no ortogonal mediante transformadas Taylor-Fourier y Legendre-Fourier.

Lasseñalesortogonalessonampliamenteutilizadasenlosmodems(Modulator-Demodulador) de los sistemas de comunicaciones digitales para la generación y descomposición formas de onda portadoras de información. Particularmente, el esquema OFDM (Ortogonal Frequency Division Multiplexing) se basa en la modulación en paralelo de un conjunto de subportadoras sinusoidales ortogonales las cuales subdividen el canal de comunicaciones en un conjunto de subcanales independientes de banda angosta. Esta división permite la implementación eficiente del modem OFDM con procesamiento puramente digital mediante algoritmos DFT (Digital Fourier Transform), reduciendo así la complejidad inherente al uso de bancos deosciladores analógicos tanto en el transmisor y como en el receptor. La idea objetivo del presente trabajo es modelado, simulación computacional, evaluación de un esquema de modulación con funciones base noortogonales. Tales funciones corresponden a los elementos de los modelos de señal de las transformadas TF (Taylor-Fourier) y LF (Legendre Fourier), utilizados para análisis de señales de SEP (Sistemas Eléctricos de Potencia). Este par de modelos puede potencialmente expandir la base de señalización OFDM y permitir un incremento en la cantidad de información binaria transmitida dado que los modelos LF y TF pueden ser vistos como expansiones de la base DFT por medio un conjunto de funciones polinómicas (Términos Taylor o Polinomios de Legendre) a costa de una mayor sensibilidad al ruido. En la presente tesis se discuten primero los fundamentos de las expansiones en bases no ortogonales mediante el concepto de pares biortogonales. Esto incluyendo su implementación discreta por medio de la matriz pseudoinversa y resaltado el papel de la matriz gramiana en el problema de dependencia lineal y sensibilidad al ruido de la base no ortogonal. Luego son expuestos el par de modelos de señal TF & LF junto con sus características temporales y frecuenciales, así como la dependencia de su matriz gramiana con los parametros de diseño del par de modelos. Por último son evaluados los criterios de probabilidad de error en condiciones de ruido blanco, ancho espectral y magnitud de las variaciones de amplitud

Compensation of Laser Phase Noise Using DSP in Multichannel Fiber-Optic Communications

One of the main impairments that limit the throughput of fiber-optic communication systems is laser phase noise, where the phase of the laser output drifts with time. This impairment can be highly correlated across channels that share lasers in multichannel fiber-optic systems based on, e.g., wavelength-division multiplexing using frequency combs or space-division multiplexing. In this thesis, potential improvements in the system tolerance to laser phase noise that are obtained through the use of joint-channel digital signal processing are investigated. To accomplish this, a simple multichannel phase-noise model is proposed, in which the phase noise is arbitrarily correlated across the channels. Using this model, high-performance pilot-aided phase-noise compensation and data-detection algorithms are designed for multichannel fiber-optic systems using Bayesian-inference frameworks. Through Monte Carlo simulations of coded transmission in the presence of moderate laser phase noise, it is shown that joint-channel processing can yield close to a 1 dB improvement in power efficiency. It is further shown that the algorithms are highly dependent on the positions of pilots across time and channels. Hence, the problem of identifying effective pilot distributions is studied.The proposed phase-noise model and algorithms are validated using experimental data based on uncoded space-division multiplexed transmission through a weakly-coupled, homogeneous, single-mode, 3-core fiber. It is found that the performance improvements predicted by simulations based on the model are reasonably close to the experimental results. Moreover, joint-channel processing is found to increase the maximum tolerable transmission distance by up to 10% for practical pilot rates.Various phenomena decorrelate the laser phase noise between channels in multichannel transmission, reducing the potency of schemes that exploit this correlation. One such phenomenon is intercore skew, where the spatial channels experience different propagation velocities. The effect of intercore skew on the performance of joint-core phase-noise compensation is studied. Assuming that the channels are aligned in the receiver, joint-core processing is found to be beneficial in the presence of skew if the linewidth of the local oscillator is lower than the light-source laser linewidth.In the case that the laser phase noise is completely uncorrelated across channels in multichannel transmission, it is shown that the system performance can be improved by applying transmitter-side multidimensional signal rotations. This is found by numerically optimizing rotations of four-dimensional signals that are transmitted through two channels. Structured four-dimensional rotations based on Hadamard matrices are found to be near-optimal. Moreover, in the case of high signal-to-noise ratios and high signal dimensionalities, Hadamard-based rotations are found to increase the achievable information rate by up to 0.25 bits per complex symbol for transmission of higher-order modulations

Data transmission oriented on the object, communication media, application, and state of communication systems tactical communication system application

A proposed communication system architecture is denoted TOMAS, which stands for data Transmission oriented on the Object, communication Media, Application, and state of communication Systems. Given particular tactical communication system scenarios of image transmission over a wireless LOS (Line-of-Sight) channel, a wireless TOMAS system demonstrates superior performance compared to the conventional system, which is a combination of JPEG2000 image compression and OFDM transmission, in restored image quality parameters over a wide range of wireless channel parameters. The wireless TOMAS system provides progressive lossless image transmission under the influence of moderate fading without any kind of channel coding and estimation. The TOMAS system employs a fast proprietary patent pending algorithm Sabelkin (2011), which does not employ any multiplications, and it uses three times less real additions than the algorithm of JPEG2000+OFDM. The TOMAS system exploits a specialized wavelet transform combined for image coding and channel modulation

Survey of FPGA applications in the period 2000 – 2015 (Technical Report)

Romoth J, Porrmann M, Rückert U. Survey of FPGA applications in the period 2000 – 2015 (Technical Report).; 2017.Since their introduction, FPGAs can be seen in more and more different fields of applications. The key advantage is the combination of software-like flexibility with the performance otherwise common to hardware. Nevertheless, every application field introduces special requirements to the used computational architecture. This paper provides an overview of the different topics FPGAs have been used for in the last 15 years of research and why they have been chosen over other processing units like e.g. CPUs

Hybrid optical fiber-wireless communication to support tactile internet

5G technologies are systems that will set to change the way people, devices and machines connect. This generation of mobile services provide connection in just one click. The advanced 5G infrastructure, defined as “ubiquitous ultra-broadband network supporting future Internet”, represents a revolution in the telecommunications field. It will enable new secure and reliable services to everyone and everything with ultra-low latency. “Full Immersive Experience”, enriched by “Context Information” and “Anything as a Service” are the main drivers for a substantial adoption of the fifth generation networks [1]. The technical challenges that must be taken into account in the design of the 5G system are many and unprecedented. Therefore,5G is expected to be about 10 times faster than LTE-4G, in addition, it is projected that this network will have100-1000 times higher system capacity, user data rates in the order of Gbps everywhere, 10-100 higher number of connected devices per area, latency in the order of 1 millisecond, and 10 times longer battery life for devices. Due to all these technological changes, for years, researchers, suppliers and manufacturers around the world have studied this new network. In order to transform the user's wireless experience and be able to offer fast generalized connectivity anytime, anywhere, to any device.[2]. All this requires an enabler in the new approach of radio access networks, which could be hybrid optical Fiber-Wireless communications. “Photonics technology has been recognized by the European Union as a Key Enabling Technology (KET), which is a technology that enables a market, many times larger than the market of technology itself”. Photonic techniques have become key enablers to unlock future broadband wireless communications with terabit data rates in order to support the current trends of mobile data traffic[3]. The aim of this thesis is to conceive experimentally and validate 1 millisecond latency hybrid optical Fiber-Wireless access links support for tactile Internet taking into account the system requirements. For this purpose, first a review about the implementation of high-speed data links at 75-110 GHz band with low latency was made. Likewise, this work summarizes the components of hybrid optical Fiber-Wireless communication in W- Band. Second, measurements of the delay contribution from individual elements in the W -Band hybrid system were made. In addition, the main contribution was to develop a procedure for measuring latency physically using software defined radio (SDR) and estimating the overall system latency. In this procedure, potential sources of delay can be identified in current high-data-rate hybrid optical-RF communication systems. After knowing how to measure latency in a hybrid optical Fiber-Wireless system, the following objectives were developed: to test an appropriate multiplexing scheme such as Orthogonal Frequency Division Multiplexing (OFDM), and Generalized Frequency Division Multiplexing (GFDM), to achieve the lowest latency with improved performance; and to implement WDM (Wavelength Division Multiplexing) to achieve the required low latency.Resumen: Las tecnologías 5G son sistemas de generación de servicios móviles configurados para cambiar la forma en que las personas, los dispositivos y las máquinas se conectan. La infraestructura 5G está definida como una red ubicua de banda ultra-ancha que soportará Internet en el futuro, dicha red representa una revolución en el campo de las telecomunicaciones. Permitirá eficientemente nuevos servicios ultra-confiables, rápidos y seguros, preservando la privacidad y acelerando los servicios críticos para todos y para cada cosa. Estas redes son la evolución del Internet de las cosas, en donde cada una de ellas es tratada como un objeto cognitivo formando sistemas cibernéticos (CPS). La "experiencia de inmersión total", enriquecida con "información de contexto" y "todo como un servicio" son los principales impulsores para una adopción masiva de los nuevos componentes de ésta tecnología y su aceptación del mercado [1]. Se espera que 5G sea aproximadamente 10 veces más rápido que 4G LTE. Por lo tanto, los desafíos técnicos que deben abordarse en el diseño del sistema 5G son muchos y sin precedentes. Actualmente hay varias actividades en todo el mundo para capturar las aplicaciones y los requisitos para 5G, algunas empresas proveedoras de servicio y fabricantes incluso ya han realizado pruebas para la implementación de dichas redes. Algunos de los principales requisitos que demandan estas redes se pueden resumir en: 100-1000 veces más capacidad del sistema, tasas de datos de usuario en el orden de Gbps en todas partes, latencia en el orden de 1 milisegundo, 10-100 veces mayor número de dispositivos conectados por área, 10 veces más duración de la batería para dispositivos. Estos requisitos transformarán dramáticamente la experiencia inalámbrica de un usuario en un sistema 5G al ofrecer conectividad generalizada rápida en cualquier momento, en cualquier lugar, a cualquier dispositivo [2]. Todo esto requiere un habilitador en el nuevo enfoque de las redes de acceso por radio, que podrían ser comunicaciones híbridas de fibra óptica y transmisiones inalámbricas vía radio. La fotónica por su parte ha sido reconocida por la Unión Europea como una Tecnología Clave Habilitadora (KET), una tecnología que permite un mercado que es muchas veces más grande que el mercado de la tecnología en sí. Las técnicas fotónicas combinadas con la generación de microondas en lo que se conoce en su término en inglés como microwave-photonics se han convertido en habilitadores clave para desbloquear futuras comunicaciones inalámbricas de banda ancha con tasas de datos de terabit a fin de soportar las tendencias actuales del tráfico de datos móviles [3]. El objetivo de esta tesis es concebir experimentalmente y validar enlaces de acceso híbridos de fibra óptica-radio, cuya latencia sea de 1 milisegundo con el fin de soportar Internet táctil, el cual es una aplicación de 5G, teniendo en cuenta los requisitos del sistema. Para ello, primero se realizó una investigación sobre la implementación de enlaces de datos con redes híbridas fibra óptica-radio en la banda de 75-110 GHz con baja latencia. Con esto, se analizaron los componentes de la comunicación híbrida fibra ópticaradio en la banda W. En segundo lugar, se realizaron mediciones de los retardos que se generan en cada uno de los elementos en el sistema híbrido de banda W, haciendo la estimación de la latencia general del sistema e identificando fuentes potenciales de demora en los sistemas híbridos de comunicación óptica-RF de alta velocidad de datos. La principal contribución de este trabajo fue el desarrollo de un procedimiento para medir la latencia utilizando radio definida por software (SDR), además de introducir estos sistemas en los enlaces híbridos fibra óptica-radio. Una vez conocido como medir la latencia en un sistema híbrido de fibra óptica-radio, los siguientes objetivos que se desarrollaron fueron: probar un esquema de multiplexación apropiado, como la multiplexación por división de frecuencia ortogonal (OFDM) y la multiplexación por división de frecuencia generalizada (GFDM), para lograr una latencia más baja. A su vez, implementar Multiplexación por división de longitud de onda (WDM) para conocer la latencia y la confiabilidad en cuanto a tasa de error de bits variando la multiplexacion eléctrica y óptica.Doctorad