Passive radar is a technology for detection of targets using echoes of existing radio transmitter, such as FM-radio. Since only receivers are needed for operation, a passive radar system has the possibility of being implemented using low-cost hardware. Using lower cost implementations to cover blind-spots of other, more sophisticated systems, could be a viable solution for full radar coverage. To achieve this, an understanding of the effects such low-cost systems have on the performance of a radar is needed.  A prominent problem for passive radar is that the interference caused by the direct signal from the transmitter used and reflections from uninteresting terrain, called clutter, can drown out the echoes from targets. This thesis compares the direct signal interference (DSI) suppression algorithms: ECA, ECA-S, ECA-B, NLMS and FBNLMS when run on data from a low-cost receiver called KerberosSDR. It is found that the low ADC resolution of 8 bits is a limiting factor for KerberosSDR. Random noise in the receiver can also limit the performance. None of the tested algorithms are any more or less affected by the ADC resolution or the noise. The first difference appears when comparing the execution times, where FBNLMS is 10–20 times faster than the other algorithms. However, the slower rate of convergence for FBNLMS and NLMS causes them to lose performance in environments where the DSI and clutter are considerably stronger than the target echoes. The algorithms FBNLMS and NLMS also lose performance due to their inability to model frequency shifted echoes as unwanted. The main disadvantages of ECA, ECA-B and ECA-S are their long execution time. It is concluded that FBNLMS would be the best candidate in most cases for low-cost hardware, as it allows execution on slower hardware and the main disadvantages not being too prominent in the use case of covering blind-spots of other systems.

L’utilisation de matrice de portes logiques reconfigurables (FPGA) est une des seules solutionspour traiter des flux de plusieurs 100 MÉchantillons/seconde en temps-réel. Toutefois, ce typede composant présente une grande difficulté de mise en oeuvre : au delà d’un type langage spécifique,c’est tout un environnement matériel et une certaine expérience qui sont requis pourobtenir les traitements les plus efficaces. Afin de contourner cette difficulté, de nombreux travauxont été réalisés dans le but de proposer des solutions qui, partant d’un code écrit dans unlangage de haut-niveau, vont produire un code dans un langage dédié aux FPGAs. Nos travaux,suivant l’approche d’assemblage de blocs et en suivant la méthode du skeleton, ont visé à mettreen place un logiciel, nommé CoGen, permettant, à partir de codes déjà développés et validés,de construire des chaînes de traitements en tenant compte des caractéristiques du FPGA cible,du débit entrant et sortant de chaque bloc pour garantir l’obtention d’une solution la plus adaptéepossible aux besoins et contraintes. Les implémentations des blocs de traitements sont soitgénérés automatiquement soit manuellement. Les entrées-sorties de chaque bloc doivent respecterune norme pour être exploitable dans l’outil. Le développeur doit fournir une descriptionconcernant les ressources nécessaires et les limitations du débit de données pouvant être traitées.CoGen fournit à l’utilisateur moins expérimenté une méthode d’assemblage de ces blocsgarantissant le synchronisme et cohérence des flux de données ainsi que la capacité à synthétiserle code sur les ressources matérielles accessibles. Cette méthodologie de travail est appliquéeà des traitements sur des flux vidéos (seuillage, détection de contours et analyse des modespropres d’un diapason) et sur des flux radio-fréquences (interrogation d’un capteur sans-fils parméthode RADAR, réception d’un flux modulé en fréquence, et finalement implémentation deblocs de bases pour déporter le maximum de traitements en numérique). / Using Field Programmable Gate Arrays (FPGA) is one of the very few solution for real time processingdata flows of several hundreds of Msamples/second. However, using such componentsis technically challenging beyond the need to become familiar with a new kind of dedicateddescription language and ways of describing algorithms, understanding the hardware behaviouris mandatory for implementing efficient processing solutions. In order to circumvent these difficulties,past researches have focused on providing solutions which, starting from a description ofan algorithm in a high-abstraction level language, generetes a description appropriate for FPGAconfiguration. Our contribution, following the strategy of block assembly based on the skeletonmethod, aimed at providing a software environment called CoGen for assembling various implementationsof readily available and validated processing blocks. The resulting processing chainis optimized by including FPGA hardware characteristics, and input and output bandwidths ofeach block in order to provide solution fitting best the requirements and constraints. Each processingblock implementation is either generated automatically or manually, but must complywith some constraints in order to be usable by our tool. In addition, each block developer mustprovide a standardized description of the block including required resources and data processingbandwidth limitations. CoGen then provides to the less experienced user the means to assemblethese blocks ensuring synchronism and consistency of data flow as well as the ability to synthesizethe processing chain in the available hardware resources. This working method has beenapplied to video data flow processing (threshold, contour detection and tuning fork eigenmodesanalysis) and on radiofrequency data flow (wireless interrogation of sensors through a RADARsystem, software processing of a frequency modulated stream, software defined radio).

The exponential growth of research and deployment of 5G networks has led to an increased interest in massive Machine Type Communications (mMTC), as we are on the quest to connect all devices. This can be attributed to the constant development of long-distance and low-powered Internet-of- Things (IoT) technologies, or, Low Power Wide Area Network (LPWAN) technologies such as Long-Range (LoRa) and Narrow Band- IoT (NB-IoT). These technologies are gaining prominence in the IoT domain as the number of LPWAN connected devices has doubled from 2018 to 2019. This increase in devices warrants a proportional number of gateways to push the data to the Internet for further analytics. The traditional LPWAN architectures do not provide dynamic scaling of resources or energy-efficient solutions. Thus, a Cloud-Native (CN) split architecture based on the functional characteristics of the components is a necessity. In this work, a software-based implementation of the LoRa stack on GNU Radio is designed and implemented using Software-Defined Radio (SDR). The LoRa gateway is implemented in software completely, replicating the functions of the hardware for communicating with any LoRa Network Server. Several experiments with different setups have been performed on the testbed to measure the resource utilization and packet delay of the LoRa Physical (PHY) and Medium Access Control (MAC) layers. Also, the testbed has been moved into Docker containers to emulate a cloud-based platform and make the transition faster. Higher throughput and lower delay (Improvement in the range of 1.3x - 6.7x) were recorded upon splitting the testbed into Radio Head (RH) and Edge containers. Finally, three potential functional split architectures including the gateway have been discussed while providing a fair trade-off between pooling gain and consumed bandwidth for a CN split architecture. / Den exponentiella tillväxten av forskning och distribution av 5G-nät har lett till ett ökat intresse för massive Machine Type Communicationsn (mMTC) eftersom vi är på jakt att ansluta alla enheter. Detta kan tillskrivas den ständiga utvecklingen av långdistans- och lågdrivna Internet-of-Things-teknologier (IoT) -teknologier, eller, Low Power Wide Area Network (LPWAN) tekniker som Long-Range (LoRa) och Narrow Band- IoT (NB-IoT). Dessa teknologier blir framträdande inom IoT-domänen eftersom antalet LPWAN-anslutna enheter har fördubblats från 2018 till 2019. Denna ökning av enheterna motiverar ett proportionellt antal portar för att driva data till Internet för ytterligare analys. De traditionella LPWAN-arkitekturerna ger inte dynamisk skalning av resurser eller energieffektiva lösningar. Således är en moln-infödd delad arkitektur baserad på funktionernas egenskaper hos komponenterna en nödvändighet. I detta arbete designas och implementeras en programvarubaserad implementering av LoRa-stacken på GNU Radio med hjälp av Software- Defined Radio (SDR). LoRa-gatewayen implementeras i mjukvara fullständigt, vilket replikerar maskinvarans funktioner för att kommunicera med någon LoRaNetwork Server. Flera experiment med olika inställningar har utförts på testbädden för att mäta resursutnyttjandet och paketfördröjningen för LoRa Physical (PHY) och Medium Access Control (MAC) -skikten. Testbädden har också flyttats in i Docker-behållare för att emulera en molnbaserad plattform och göra övergången snabbare. Högre genomströmning och lägre fördröjning (Förbättring inom intervallet 1,3x - 6,7x) registrerades vid uppdelning av testbädden i Radio Head (RH) och Edge containrar. Slutligen har tre potentiella funktionella splitarkitekturer inklusive gateway diskuterats samtidigt som det ger en rättvis avvägning mellan pooling av vinst och förbrukad bandbredd.

International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / The ISM bands have opened up new opportunities for telemetry using spread-spectrum communications. A low-cost frequency-hopping radio is described here for the 900 MHz ISM band that can be programmed with a wide range of hop and data rates. The ‘C6201 DSP from TI is used to control the frequency and data rate of the TI TRF6900 transceiver chip using a custom interface of the 6201 EVM board to the serial I/O on the 6900 evaluation board.

This paper will present the hardware system design, development, and plan for implementation of a wireless transceiver for The Learning Labs 5000 (TLL5000) educational platform. The project is a collaborative effort by Vanessa Canac, Atif Habib, and Jason Perkey to design and implement a complete wireless system including physical hardware, physical layer (PHY-layer) modulation and filters, error correction, drivers and user-interface software. While there are a number of features available on the TLL5000 for a wide variety of applications, there is currently no system in place for transmitting data wirelessly from one circuit board to another. The system proposed in this report is comprised of an external transceiver that communicates with a software application running on the TLL-SILC 6219 ARM9 processor that is interfaced with the TLL5000 baseboard. The details of a reference design, the hardware from the GNU Radio project, are discussed as a baseline and source of information. The state of the project and hardware design is presented as well as the specific portions of the project to which Jason Perkey made significant contributions. / text

We have implemented a TDOA multilateration of transmitters on an unmodified rtl-sdr receiver using transmitters with known location as a timing reference. We present a brief theoretical background and describe the measurement process which includes several approaches that correct the timing and frequency errors between the receivers. Additionally, we have implemented an angle of arrival direction finder using coherent rtl-sdr.

This thesis describes a real-time software-defined-radio implementation of the time-slotted round-trip carrier synchronization protocol in two-source and three-source communication systems. The techniques developed in this thesis can be used to synchronize the carriers of two or three single-antenna wireless transmitters with independent local oscillators so that their band-pass transmissions combine constructively at an intended receiver. Synchronization is achieved via the time-slotted transmission of (i) an unmodulated primary beacon from the destination to the sources and (ii) a series of secondary unmodulated beacons between the sources. Explicit channel state information is not exchanged between the sources and/or the destination. When synchronized, the single-antenna sources are able to cooperatively transmit as a distributed beamformer and achieve increased transmission range, reduced transmission energy, and/or increased security. The experimental results in this thesis confirm the theoretical predictions and also provide explicit guidelines for the real-time implementation of a carrier synchronization technique suitable for distributed transmit beamforming.

Wireless channel characterization is important for determining both the requirements for a wireless system and its resulting reliability. Wireless systems are becoming ever more pervasive and thus are expected to operate in increasingly more cluttered environments. While these devices may be fixed in location, the channel is still far from ideal due to multipath. Under such conditions, it is desirable to have a means of taking wireless channel measurements in a low-cost and distributed manner, which is not always possible using typical channel measurement equipment. This thesis leverages a software-defined radio (SDR) platform to perform wideband wireless channel measurements. Specifically, the system can measure the scalar frequency response of a wireless channel in a distributed manner and provides measurements with an average mean-squared error of 0.018 % σ and a median error not exceeding 0.631 dB when compared to measurements taken with a vector network analyzer. This accuracy holds true in a highly multipath environment, with a measurement range of ~40 dB. The system is also capable of scaling to multiple wireless links which will be measured simultaneously (up to three links are demonstrated). After validating the measurement system, a measurement campaign is undertook using the system in a highly multipath environment to demonstrate a possible application of the system.

<p><p>In order to keep up with the increasing demand on speed and reliability in modern wireless systems, new standards have to be introduced. By using Multiple Input Multiple Output technology (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) technologies the performance can be increased dramatically. Forthcoming standards such as WLAN 802.11n, WiMax and 3GPP LTE are all taking advantage of MIMO technology. To perform realistic tests with these standards it is often not enough to run software simulations in for example Matlab. Instead, as many real world parameters as possible need to be included. This can be done using a testbed, like the LiUMIMO, that actually transmits and receives data through the air.</p><p>The LiUMIMO is designed as a Software Defined Radio (SDR), only the RF front end and the data log are implemented in hardware, while all signal processing will be performed in Matlab.</p></p>

Our research aims at contributing to the evolution of modern wireless communications and to the development of software-defined radio (SDR) and cognitive radio, in particular. It promotes a general resource management framework that facilitates the integration of computing and radio resource management. This dissertation discusses the need for computing resource management in software-defined and cognitive radios and introduces an SDR computing resource management framework with cognitive capabilities. The hard real-time computing requirements of software-defined digital signal processing chains (SDR applications), the associated radio propagation and quality of service (QoS) implications, and heterogeneous multiprocessor platforms with limited computing resources (SDR platforms) define the context of these studies. We examine heterogeneous computing techniques, multiprocessor mapping and scheduling in particular, and elaborate a flexible framework for the dynamic allocation and reallocation of computing resources for wireless communications. The framework should facilitate partial reconfigurations of SDR platforms, dynamic switches between radio access technologies (RATs), and service and QoS level adjustments as a function of the environmental conditions. It, therefore, assumes the facilities of the platform and hardware abstraction layer operating environment (P-HAL-OE). We suggest a modular framework, distinguishing between the computing system modeling and the computing resource management. Our modeling proposal is based on two computing resource management techniques, which facilitate managing the strict timing constraints of real-time systems. It is scalable and can account for many different hardware architectures and computing resource types. This work focuses on processing and interprocessor bandwidth resources and processing and data flow requirements. Our computing resource management approach consists of a general-purpose mapping algorithm and a cost function. The independence between the algorithm and the cost function facilitates implementing many different computing resource management policies. We introduce a dynamic programming based algorithm, the tw-mapping, where w controls the decision window. We present a general and parametric cost function, which guides the mapping process under the given resource constraints. An instance of it facilitates finding a mapping that meets all processing and data flow requirements of SDR applications with the available processing and bandwidth resources of SDR platforms. Several SDR reconfiguration scenarios and analyses based on simulations demonstrate the suitability and potentials of our framework for a flexible computing resource management. We extend our SDR computing resource management concepts to the cognitive radio context. The two primary objectives of cognitive radio are highly reliable communications whenever and wherever needed and the efficient use of the radio spectrum. We formulate a third objective as the efficient use of computing resources. We analyze the cognitive capabilities of our framework─the cognitive radio’s interface to SDR platforms─and indicate the potentials of our cognitive computing resource management proposal. The cognitive computing resource management needs to be coordinated with the radio resource management. We, therefore, introduce the joint resource management concept for cognitive radios. We present three cognitive cycles and discuss several interrelations between the radio, computing, and application resources, where application resources refer to the available SDR and user applications. Our approach potentiates flexibility and facilitates radio against computing resource tradeoffs. It promotes cognition at all layers of the wireless system for a cooperative or integrated resource management that may increase the performance and efficiency of wireless communications. / El objetivo de las investigaciones que se están llevando a cabo dentro del grupo de investigación es contribuir a la evolución de las radiocomunicaciones modernas y, en particular, al desarrollo de los conceptos software radio (SDR) y cognitive radio. El planteamiento general es el de extender la flexibilidad global del sistema de comunicaciones planteando la definición y desarrollo de un entorno en el que pudiesen explorarse las relaciones entre la computación y las prestaciones del sistema de comunicaciones móviles facilitando la integración de los recursos de computación con los recursos radio. Dentro de este marco, la presente tesis plantea la discusión de la necesidad de la gestión de los recursos de computación en entornos SDR y cognitive radio y define un entorno de operación que asume las características especificas del concepto SDR a la vez que incorpora capacidades cognitivas en la gestión de los recursos de computación de las plataformas que den soporte a las nuevas generaciones de sistemas móviles. Los estrictos requerimientos de procesado en tiempo real de las cadenas de procesado digital de la señal definidas por software (aplicaciones SDR), las implicaciones asociadas con la propagación radio y el concepto de calidad de servicio (QoS) y plataformas heterogéneas de múltiples procesadores con recursos de computo limitados (plataformas SDR) definen el contexto de estos estudios. Se examinan técnicas de cómputo de propósito general para definir un entorno de operación que fuese capaz de asignar de forma flexible y dinámica los recursos de cómputo necesarios para facilitar las radiocomunicaciones a los niveles de QoS deseados. Ello debería facilitar los cambios dinámicos de una tecnología de acceso radio a otra, permitiendo el ajuste del tipo de servicio o calidad de servicio en función de las preferencias de los usuarios y las condiciones del entorno. Dicho entorno de operación asume las potencialidades del platform and hardware abstraction layer operating environment (P-HAL-OE). La estructura del entorno de operación se define de forma modular y consiste en un modelado genérico y flexible de las plataformas de computación SDR y en una gestión de recursos de computación abierta y capaz de ajustarse a diferentes objetivos y políticas. En el trabajo se exponen dos técnicas de gestión que pretenden asegurar la consecución estricta de los límites temporales típicos de los sistemas en tiempo real. En cuanto al modelado, este es escalable y capaz de capturar un amplio abanico de arquitecturas hardware y recursos de computación. En el presente trabajo nos centramos en los recursos y requerimientos del procesado y transferencia de datos. Se introduce un algoritmo de mapeo genérico e independiente de la función de coste. La independencia entre el algoritmo y la función de coste facilita la implementación de diferentes políticas de gestión de recursos computacionales. El tw-mapping es un algoritmo basado en dynamic programming, donde w controla la ventana de decisión. Se presenta una función de coste genérica y parametrizable que permite guiar el proceso de gestión de los recursos. Una instancia de ella facilita encontrar una solución al proceso de asignación de recursos que cumpla todos los requerimientos de procesado y trasferencia de datos de las aplicaciones SDR con los recursos disponibles de las plataformas SDR. Diferentes escenarios y varios análisis basados en simulaciones demuestran la adecuación del entorno de trabajo definido y desarrollado, así como sus potencialidades para una gestión flexible de los recursos de cómputo. Se extienden los conceptos mencionados previamente para entornos cognitive radio. Los principales objetivos del concepto cognitive radio son la disponibilidad de comunicaciones altamente robustas en cualquier lugar y momento en que sean necesarias y el uso eficiente del espectro. Como tercer objetivo formulamos el uso eficiente de los recursos de cómputo. Analizamos las capacidades cognitivas de nuestro entorno de operación─la interfaz del sistema cognitive radio a las plataformas SDR─y resaltamos las potencialidades de nuestra propuesta de gestión cognitiva de los recursos computacionales. Dicha gestión cognitiva de los recursos computacionales plantea una integración con la gestión de los recursos radio. Para ello introducimos el concepto de gestión de recursos conjunta para entornos cognitive radio. Se presentan tres ciclos cognitivos y se discuten algunas interrelaciones entre los recursos radio, de cómputo y de aplicación, donde los recursos de aplicación se refieren a las aplicaciones SDR y de usuario disponibles. Nuestra propuesta de gestión de recursos conjunta potencia la flexibilidad y facilita los intercambios entre recursos radio y de computación