Smart antennas in software radio base stations

The application of adaptive antenna techniques to fixed-architecture base stations has been shown to offer wide-ranging benefits, including interference rejection capabilities or increased coverage and spectral efficiency.Unfortunately, the actual implementation ofthese techniques to mobile communication scenarios has traditionally been set back by two fundamental reasons. On one hand, the lack of flexibility of current transceiver architectures does not allow for the introduction of advanced add-on functionalities. On the other hand, theoften oversimplified models for the spatiotemporal characteristics of the radio communications channel generally give rise toperformance predictions that are, in practice, too optimistic. The advent of software radio architectures represents a big step toward theintroduction of advanced receive/transmitcapabilities. Thanks to their inherent flexibilityand robustness, software radio architecturesare the appropriate enabling technology for theimplementation of array processing techniques.Moreover, given the exponential progression ofcommunication standards in coexistence andtheir constant evolution, software reconfigurabilitywill probably soon become the only costefficientalternative for the transceiverupgrade. This article analyzes the requirementsfor the introduction of software radio techniquesand array processing architectures inmultistandard scenarios. It basically summarizesthe conclusions and results obtained withinthe ACTS project SUNBEAM,1 proposingalgorithms and analyzing the feasibility ofimplementation of innovative and softwarereconfigurablearray processing architectures inmultistandard settings.

Implementazione di un trasmettitore OFDM mediante software radio

L’obiettivo di questo elaborato è quello di implementare un Modem digitale che è basato su una modulazione Orthogonal Frequency Division Multiplexing (OFDM) ed è formato da due tipi di dispositivi radio differenti, i quali sono molto utili, poiché si possono utilizzare in diversi scopi senza doverne modificare l’hardware ma solo cambiando la parte software perché sono programmabili. I due dispositivi sono i seguenti: • Analog Device Adalm-Pluto: dispositivo in grado sia di trasmettere che di ricevere. Lo utilizzeremo solamente per trasmettere il segnale. • Noeelec NE-SDR: dispositivo in grado solo di ricevere. Lo utilizzeremo quindi solamente per ricevere il segnale. Il tipo di modulazione da noi utilizzata per trasmettere il segnale è come detto in precedenza la modulazione OFDM. Essa è molto efficiente nell’occupazione della banda ed applica la trasmissione di un segnale su più portanti affiancate nel dominio delle frequenze. Questo significa che ogni portante che compone il segnale completo si trova ad una frequenza multipla della principale f0. Inoltre il vantaggio di questa modulazione sta nel fatto di sapere che l’informazione è contenuta nel segnale passa-basso inviluppo complesso rappresentativo i(t) e per questo motivo vedremo, nel corso dell’elaborato, come lo schema di trasmissione e ricezione sia molto semplificato.

Implementazione di un ricevitore OFDM mediante software radio

Nel campo della trasmissione di segnali alfanumerici è cresciuto sempre di più l’interesse riguardo alla trasmissione di segnali caratterizzati da più sottoportanti affiancate nel dominio della frequenza mediante modulazione multiportante (MC, multicarrier modulation). Si è dimostrato che OFDM è un’effettiva tecnica per "combattere" il problema del multipath-fading nei canali wirless. Il multipath-fading è una forma di distorsione di un segnale che giunge a destinazione sotto forma di un certo numero di repliche, sfasate nel tempo, originate dai vari percorsi che il segnale stesso può aver seguito durante la sua propagazione e sommantesi tra loro in ricezione; ogni replica inoltre, sarà soggetta ad un’attenuazione in generale diversa da quella subita dalle altre repliche. Ciò che si vuole realizzare è un sistema di trasmissione e ricezione dati alfanumerico tramite la modulazione OFDM tramite l’utilizzo di due dispositivi SDR. In particolare per la trasmissione del segnale viene utilizzato il dispositivo ADALM-PLUTO, ed è lasciata libera scelta nel trasmettere qualsiasi tipo di segnale alfanumerico, ovvero il numero di simboli OFDM può variare a discrezione dell’utente. Per la ricezione del segnale inviato è stato impiegato il dispositivo Noolec NESDR, e l’utente, qui, sarà invece obbligato a inserire il numero di simboli OFDM da dover ricevere per avere così una corretta decodifica del segnale.

Spectrum sensing through software defined radio

Dissertação apresentada para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia

Implementation of wireless communication based on Software Defined Radio

In current communication systems, there are many new challenges like various competitive standards, the scarcity of frequency resource, etc., especially the development of personal wireless communication systems result the new system update faster than ever before, the conventional hardware-based wireless communication system is difficult to adapt to this situation. The emergence of SDR enabled the third revolution of wireless communication which from hardware to software and build a flexible, reliable, upgradable, reusable, reconfigurable and low cost platform. The Universal Software Radio Peripheral (USRP) products are commonly used with the GNU Radio software suite to create complex SDR systems. GNU Radio is a toolkit where digital signal processing blocks are written in C++, and connected to each other with Python. This makes it easy to develop more sophisticated signal processing systems, because many blocks already written by others and you can quickly put them together to create a complete system. Although the main function of GNU Radio is not be a simulator, but if there is no RF hardware components,it supports to researching the signal processing algorithm based on pre-stored and generated data by signal generator. This thesis introduced SDR platform from hardware (USRP) and software(GNU Radio), as well as some basic modulation techniques in wireless communication system. Based on the examples provided by GNU Radio, carried out some related experiments, for example GSM scanning and FM radio station receiving on USRP. And make a certain degree of improvement based on the experience of some investigators to observe OFDM spectrum and simulate real-time video transmission. GNU Radio combine with USRP hardware proved to be a valuable lab platform for implementing complex radio system prototypes in a short time. RESUMEN. Software Defined Radio (SDR) es una tecnología emergente que está creando un impacto revolucionario en la tecnología de radio convencional. Un buen ejemplo de radio software son los sistemas de código abierto llamados GNU Radio que emplean un kit de herramientas de desarrollo de software libre. En este trabajo se ha empleado un kit de desarrollo comercial (Ettus Research) que consiste en un módulo de procesado de señal y un hardaware sencillo. El módulo emplea un software de desarrollo basado en Linux sobre el que se pueden implementar aplicaciones de radio software muy variadas. El hardware de desarrollo consta de un microprocesador de propósito general, un dispositivo programable (FPGA) y un interfaz de radiofrecuencia que cubre de 50 a 2200MHz. Este hardware se conecta al PC por medio de un interfaz USB de 8Mb/s de velocidad. Sobre la plataforma de Ettus se pueden ejecutar aplicaciones GNU radio que utilizan principalmente lenguaje de programación Python para implementarse. Sin embargo, su módulo de procesado de señal está construido en C + + y emplea un microprocesador con aritmética de coma flotante. Por lo tanto, los desarrolladores pueden rápida y fácilmente construir aplicaciones en tiempo real sistemas de comunicación inalámbrica de alta capacidad. Aunque su función principal no es ser un simulador, si no puesto que hay componentes de hardware RF, Radio GNU sirve de apoyo a la investigación del algoritmo de procesado de señales basado en pre-almacenados y generados por los datos del generador de señal. En este trabajo fin de máster se ha evaluado la plataforma de hardware de DEG (USRP) y el software (GNU Radio). Para ello se han empleado algunas técnicas de modulación básicas en el sistema de comunicación inalámbrica. A partir de los ejemplos proporcionados por GNU Radio, hemos realizado algunos experimentos relacionados, por ejemplo, escaneado del espectro, demodulación de señales de FM empleando siempre el hardware de USRP. Una vez evaluadas aplicaciones sencillas se ha pasado a realizar un cierto grado de mejora y optimización de aplicaciones complejas descritas en la literatura. Se han empleado aplicaciones como la que consiste en la generación de un espectro de OFDM y la simulación y transmisión de señales de vídeo en tiempo real. Con estos resultados se está ahora en disposición de abordar la elaboración de aplicaciones complejas.

Lightweight Middleware for Software Defined Radio (SDR) Inter-Components Communication

The ability to use Software Defined Radio (SDR) in the civilian mobile applications will make it possible for the next generation of mobile devices to handle multi-standard personal wireless devices and ubiquitous wireless devices. The original military standard created many beneficial characteristics for SDR, but resulted in a number of disadvantages as well. Many challenges in commercializing SDR are still the subject of interest in the software radio research community. Four main issues that have been already addressed are performance, size, weight, and power. This investigation presents an in-depth study of SDR inter-components communications in terms of total link delay related to the number of components and packet sizes in systems based on Software Communication Architecture (SCA). The study is based on the investigation of the controlled environment platform. Results suggest that the total link delay does not linearly increase with the number of components and the packet sizes. The closed form expression of the delay was modeled using a logistic function in terms of the number of components and packet sizes. The model performed well when the number of components was large. Based upon the mobility applications, energy consumption has become one of the most crucial limitations. SDR will not only provide flexibility of multi-protocol support, but this desirable feature will also bring a choice of mobile protocols. Having such a variety of choices available creates a problem in the selection of the most appropriate protocol to transmit. An investigation in a real-time algorithm to optimize energy efficiency was also performed. Communication energy models were used including switching estimation to develop a waveform selection algorithm. Simulations were performed to validate the concept.

Ressonância magnética nuclear com recurso a um transreceptor rádio controlado por software

Dissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores

Virtual Radio Engine

Software Defined Radio (SDR) hardware platforms use parallel architectures. Current concepts of developing applications (such as WLAN) for these platforms are complex, because developers describe an application with hardware-specifics that are relevant to parallelism such as mapping and scheduling. To reduce this complexity, we have developed a new programming approach for SDR applications, called Virtual Radio Engine (VRE). VRE defines a language for describing applications, and a tool chain that consists of a compiler kernel and other tools (such as a code generator) to generate executables. The thesis presents this concept, as well as describes the language and the compiler kernel that have been developed by the author. The language is hardware-independent, i.e., developers describe tasks and dependencies between them. The compiler kernel performs automatic parallelization, i.e., it is capable of transforming a hardware-independent program into a hardware-specific program by solving hardware-specifics, in particular mapping, scheduling and synchronizations. Thus, VRE simplifies programming tasks as developers do not solve hardware-specifics manually.

Comunicação social com software livre

A tecnologização que a sociedade experimenta nas últimas décadas trouxe a profusão de máquinas informatizadas e seus sistemas de operação. Neste período a indústria desenvolveu sofisticados e caros softwares aplicativos proprietários para o pleno uso destas máquinas, o que colocou boa parte do mercado social nas mãos de poucas empresas multinacionais, entre elas, a Microsoft, e outras. Mas, o espírito libertário de membros das comunidades científicas e hackers promoveu o desenvolvimento do software livre e aberto, que pode ser usado como bem social mais amplo e, principalmente, evoluir no melhor do espírito colaborativo. O presente trabalho estuda os dois modelos de produção de software, os compara visando tornar evidentes as qualidades de cada um, seus custos, rendimentos e possibilidades de adoção. Projeta a possibilidade de que as habilitações da área da comunicação possam migrar para o modelo de software livre, dadas as plenas qualidades deste sistema, a radical redução de custos e as constatações que amplos segmentos da produção audiovisual os está adotando. Para tanto, compara as experiências aplicadas com ambos os sistemas em dois cursos de comunicação, em sua habilitação de Rádio e Televisão.(AU)

Contribución al diseño de GNSS-SDR, un receptor GNSS de código abierto

[ANGLÈS] This project introduces GNSS-SDR, an open source Global Navigation Satellite System software-defined receiver. The lack of reconfigurability of current commercial-of-the-shelf receivers and the advent of new radionavigation signals and systems make software receivers an appealing approach to design new architectures and signal processing algorithms. With the aim of exploring the full potential of this forthcoming scenario with a plurality of new signal structures and frequency bands available for positioning, this paper describes the software architecture design and provides details about its implementation, targeting a multiband, multisystem GNSS receiver. The result is a testbed for GNSS signal processing that allows any kind of customization, including interchangeability of signal sources, signal processing algorithms, interoperability with other systems, output formats, and the offering of interfaces to all the intermediate signals, parameters and variables. The source code release under the GNU General Public License (GPL) secures practical usability, inspection, and continuous improvement by the research community, allowing the discussion based on tangible code and the analysis of results obtained with real signals. The source code is complemented by a development ecosystem, consisting of a website (http://gnss-sdr.org), as well as a revision control system, instructions for users and developers, and communication tools. The project shows in detail the design of the initial blocks of the Signal Processing Plane of the receiver: signal conditioner, the acquisition block and the receiver channel, the project also extends the functionality of the acquisition and tracking modules of the GNSS-SDR receiver to track the new Galileo E1 signals available. Each section provides a theoretical analysis, implementation details of each block and subsequent testing to confirm the calculations with both synthetically generated signals and with real signals from satellites in space.

Validation of a computer-assisted system on classifying lower third molars

Objectives: The present study evaluates the reliability of the Radio Memory® software (Radio Memory; Belo Horizonte,Brasil.) on classifying lower third molars, analyzing intra- and interexaminer agreement of the results. Study Design: An observational, descriptive study of 280 lower third molars was made. The corresponding orthopantomographs were analyzed by two examiners using the Radio Memory® software. The exam was repeated 30 days after the first observation by each examiner. Both intra- and interexaminer agreement were determined using the SPSS v 12.0 software package for Windows (SPSS; Chicago, USA). Results: Intra- and interexaminer agreement was shown for both the Pell & Gregory and the Winter classifications, p<0.01, with 99% significant correlation between variables in all the cases. Conclusions: The use of Radio Memory® software for the classification of lower third molars is shown to be a valid alternative to the conventional method (direct evaluation on the orthopantomograph), for both clinical and investigational applications.

Sistema de Comunicações para as Ilhas Desertas

Esta dissertação tem como principal objectivo, propor um sistema de comunicações para as Ilhas Desertas que vise atender às necessidades expostas pelo PNM - Parque Natural da Madeira. Localizadas a 22 milhas marítimas do Funchal, as ilhas Desertas não dispõem de cobertura da rede móvel GSM - Global Standard for Mobile, nem de qualquer outra infra-estrutura de comunicações que permita a comunicação entre os vigilantes e a estação de serviço - doca. Esta falta de comunicação torna-se mais problemática aquando da realização de acções de fiscalização e vigilância, já que em caso de acidente não será possível pedir auxílio. Dada esta realidade propomos a criação de uma rede de rádio móvel terrestre para as Ilhas Desertas, com a instalação de vários repetidores UHF no topo das ilhas. O projecto desta rede será fundamentado com a realização de um estudo de cobertura para as três ilhas que incluirá a avaliação e análise de vários modelos de propagação. Esta análise é realizada com recurso a duas ferramentas de software, Radio-Mobile e DifractionLoss, tendo este último sido desenvolvido no âmbito desta dissertação. De forma a melhorar a cobertura da rede GSM na estação de serviço do PNM na Deserta Grande, sugerem-se duas soluções: a primeira consiste na instalação de um repetidor GSM de frequência deslocada e a segunda na instalação de uma NanoBTS. Além da falta de comunicação na área das ilhas Desertas, a falta de comunicação com a ilha da Madeira é também uma realidade. Perante esta situação sugere-se a criação de uma ligação por feixes hertzianos de alta frequência entre a estação de serviço do PNM na Deserta Grande e a sede do PNM, localizada na zona do Jardim Botânico na Ilha da Madeira. O projecto desta ligação apresenta um planeamento e dimensionamento de acordo com as necessidades apresentadas pelo PNM, assim como um estudo de propagação baseado num procedimento teórico e em simulações de software. É também proposto um sistema de videovigilância controlado remotamente com o objectivo de permitir a monitorização remota dos lobos-marinhos.

SDR-based Passive Indoor Localization System for GSM

This study deals with indoor positioning using GSM radio, which has the distinct advantage of wide coverage over other wireless technologies. In particular, we focus on passive localization systems that are able to achieve high localization accuracy without any prior knowledge of the indoor environment or the tracking device radio settings. In order to overcome these challenges, newly proposed localization algorithms based on the exploitation of the received signal strength (RSS) are proposed. We explore the effects of non-line-of-sight communication links, opening and closing of doors, and human mobility on RSS measurements and localization accuracy. We have implemented the proposed algorithms on top of software defined radio systems and carried out detailed empirical indoor experiments. The performance results show that the proposed solutions are accurate with average localization errors between 2.4 and 3.2 meters.

Portado del algoritmo de Viterbi a una arquitectura multiprocesador

Cada vez es más frecuente que los sistemas de comunicaciones realicen buena parte de sus funciones (modulación y demodulación, codificación y decodificación...) mediante software en lugar de utilizar hardware dedicado. Esta técnica se denomina “Radio software”. El objetivo de este PFC es estudiar un algoritmo implementado en C empleado en sistemas de comunicaciones modernos, en concreto la decodificación de Viterbi, el cual se encarga de corregir los posibles errores producidos a lo largo de la comunicación, para poder trasladarlo a sistemas empotrados multiprocesador. Partiendo de un código en C para el decodificador que realiza todas sus operaciones en serie, en este Proyecto fin de carrera se ha paralelizado dicho código, es decir, que el trabajo que realizaba un solo hilo para el caso del código serie, es procesado por un número de hilos configurables por el usuario, persiguiendo que el tiempo de ejecución se reduzca, es decir, que el programa paralelizado se ejecute de una manera más rápida. El trabajo se ha realizado en un PC con sistema operativo Linux, pero la versión paralelizada del código puede ser empleada en un sistema empotrado multiprocesador en el cual cada procesador ejecuta el código correspondiente a uno de los hilos de la versión de PC. ABSTRACT It is increasingly common for communications systems to perform most of its functions (modulation and demodulation, coding and decoding) by software instead of than using dedicated hardware. This technique is called: “Software Radio”. The aim of the PFC is to study an implemented algorithm in C language used in modern communications systems, particularly Viterbi decoding, which amends any possible error produced during the communication, in order to be able to move multiprocessor embedded systems. Starting from a C code of the decoder that performs every single operation in serial, in this final project, this code has been parallelized, which means that the work used to be done by just a single thread in the case of serial code, is processed by a number of threads configured by the user, in order to decrease the execution time, meaning that the parallelized program is executed faster. The work has been carried out on a PC using Linux operating system, but the parallelized version of the code could also be used in an embedded multiprocessor system in which each processor executes the corresponding code to every single one of the threads of the PC version.

Lightweight middleware for SDR inter-components communication

The ability to use Software Defined Radio (SDR) in the civilian mobile applications will make it possible for the next generation of mobile devices to handle multi-standard personal wireless devices and ubiquitous wireless devices. The original military standard created many beneficial characteristics for SDR, but resulted in a number of disadvantages as well. Many challenges in commercializing SDR are still the subject of interest in the software radio research community. Four main issues that have been already addressed are performance, size, weight, and power. ^ This investigation presents an in-depth study of SDR inter-components communications in terms of total link delay related to the number of components and packet sizes in systems based on Software Communication Architecture (SCA). The study is based on the investigation of the controlled environment platform. Results suggest that the total link delay does not linearly increase with the number of components and the packet sizes. The closed form expression of the delay was modeled using a logistic function in terms of the number of components and packet sizes. The model performed well when the number of components was large. ^ Based upon the mobility applications, energy consumption has become one of the most crucial limitations. SDR will not only provide flexibility of multi-protocol support, but this desirable feature will also bring a choice of mobile protocols. Having such a variety of choices available creates a problem in the selection of the most appropriate protocol to transmit. An investigation in a real-time algorithm to optimize energy efficiency was also performed. Communication energy models were used including switching estimation to develop a waveform selection algorithm. Simulations were performed to validate the concept.^