Talks from GNU Radio Days 2019

GNU Radio Days 2019 was a workshop held back in June. Within the last week recordings of the talks have been uploaded to YouTube by the Software Defined Radio Academy channel. The talks cover a wide range of cutting edge SDR research topics and projects. Many of the presenters have also made use of RTL-SDR dongles, as well as other higher end SDRs in their research.

All the talks are combined into two 3 hour long videos from the morning and day sessions from day one. Day two also has two videos that consist of recordings from the tutorial sessions which make use of the PlutoSDR. Finally there is also the keynote speech from Marcus Müller where he dives into the internal workings of GNU Radio.

Below we list the talks with timestamps for the YouTube video. Short text abstracts for each of the talks can also be found in the conference book. We note that not all the abstracts appear to have been presented in the videos, so it may be worth checking out the book for missed talks about passive radar, a 60 GHz link, embedded GNU Radio on a PlutoSDR, an SDR 802.11 infrared transmission system, PHY-MAC layer prototyping in dense IoT networks and hacking the DSMx Drone RC protocol.

Day One: Morning Session

00:19:00 - Array signal processing optimization in GNU Radio for tracking and receiving applications, Bieber E [et al.] 

Among other missions the French German research Institute of Saint-Louis (ISL) works on array signal processing for secured communications between high speed projectiles and allied base stations. Within that framework, a projectile tracking receiving station based on commercial Software-Defined Radios (SDR) was developed using four channels to steer an antenna array and recombine the received signals, hence improving the gain of the receiving station. A transmitter embedded in the projectile sent data to the developed receiving station at a 2 Mbits/s. In order to decode and process in real time the data received by the four channel antenna array, a high sampling rate was required. As this highly resource consuming application resulted in sample overflows that is, in periodic losses of data between the SDR and the computer, an optimization of our algorithms computed on GNU Radio and the communication between our blocks proved to be necessary. This paper intends to provide feedback on our optimization work. Some of the main problems we encountered and the solutions we propose to solve them are briefly exposed and will be further detailed in our oral presentation

00:43:00 - SatNOGS: Towards a Modern, Crowd Sourced and Open Network of Ground Stations, Julien Nicolas 

Over the last years the launching cost of a payload in space has been significantly reduced and this trend is expected to continue, as the interest for space applications is increasing. The reduced launch cost and the advancements in technology, gave the opportunity to small satellites to revolutionize access to space.

The majority of the small satellites missions are targeting the Low Earth Orbit (LEO). Due to the nature of this particular orbit, communication with a satellite is possible only for a few minutes per day for a given location. This raises the need for multiple ground stations in several geographic locations. Although such an infrastructure is possible, most of the times it is both complicated and expensive for research or educational entities to obtain. Given the fact that each ground station exhibits a small per day utilization for a specific satellite, the idle time can be used for reception of other missions. SatNOGS is an open source software and open hardware project that addresses this problem by interconnecting all participating ground stations, offering their idle time to other users of the SatNOGS
network.

1:10:40 - Using GNU Radio to do signal acquisition and analysis with Scopy

1:37:30 - Embedded and Connected Receiver System for nano-satellite in Low Earth Orbit (LEO), Spies Francois [et al.] 

The objective of this work is to design a set of satellite signal reception, embedded, connected and low power consumption. This set must be simple to implement with the ambition of being widely deployed on a global scale to provide complete and continuous coverage so that each satellite transmission can be received at any time without loss. The altitude of the satellite orbit must allow the planet to be covered with less than a hundred reception stations on earth. The stations will be located mainly in universities with an eduroam connection to facilitate the transmission of information on a server.

1:59:40 - KiwiSDR as a new GNURadio source, Mayer Christoph

By now, >300 world-wide distributed KiwiSDRs are online. After introducing the KiwiSDR, an implementation of a GNURadio websocket client for the KiwiSDR. As an example on how to use the GNURadio KiwiSDR client, the coherent combination of KiwiSDR IQ streams, and decoders implemented in GNURadio for digital HF modes using the KiwiSDR client are shown.

2:30:20 - Using GNU Radio Companion to improve student understanding of signal processing theory through VHF Omni-Directional Range (VOR) signal demodulation, Blais Antoine [et al.]

The École Nationale de l'Aviation Civile (ENAC), the French Civil Aviation University, proposes a graduate engineer program with, among three others, a major, in Aeronautical and Space Telecommunications (SAT). This major is characterized by advanced theoretical courses in signal theory, signal processing, digital communications and navigation in particular. Some practicals are given to help the students understanding specific points in these courses. However, this scattered approach does not provide any hindsight on the interest and the usefulness of these courses, either independently nor together. This is the reason why these practicals are completed by a long project which proposes, as a global case of application, to demodulate a VHF Omni-Directional Range (VOR) signal. This paper details this long project, from its pedagogical approach to some interesting points of its implementation.

Day One: Afternoon Session

00:00:30 - VLBI with GNU Radio, RFNoC and White Rabbit, Boven Paul

00:35:25 - Fully Digital Electronics for Fiber-Link Frequency Transfer Implemented on Red Pitaya, Cardenas Olaya Andrea Carolina [et al.] 

This paper presents a digital instrumentation for frequency transfer on optical fiber links. The proposed system detects the phase and amplitude of the beatnotes at the two ends of the fiber for (actively or passively) compensating by the phase noise and the polarization rotation. The implementation is performed on Red Pitaya, an open source platform that integrates fast Analog-to-Digital and Digitalto-Analog converters with a Zynq System-on-Chip. The system features a detection bandwidth of 10 MHz, compatible with thousand kilometers links, that can be finely tuned for reaching an adequate Signal-to-Noise Ratio minimizing the generation of cycle slips.

00:56:30 - Frequency locking a laser on a spectral hole pattern with a multi-channel heterodyne method using SDR and GnuRadio, Galland N [et al.]

High precision spectroscopic probing of a narrow spectral hole pattern imprinted in the inhomogeneously broadened absorption spectrum of Eu3+ : Y2SiO5 crystal can be used to stabilize a laser frequency. A multi-hole pattern can be burn and all the holes can be probed simultaneously using a multiple frequency signal. The dispersion induced dephasing acquired by the light through the crystal is measured to derive an error signal suitable to lock the laser frequency to the spectral hole pattern. An Ettus USRP X310 driven by a python program based on GNU Radio is used for both generating the multiple frequency signal and to compute the correction applied to the laser frequency.

1:23:50 - A LoRaWAN Security Assessment Test Bench, Claverie Tristan [et al.]

LoRaWAN is a recent protocol and despite having been already studied from a security perspective, several attacks have not been reproduced in practice mostly due to a lack of details regarding the test benches used. After presenting previous work on the LoRaWAN protocol and the various platforms described, we present an environment based on hardware, software and SDR to study the radio layer of the protocol. The efficiency of this architecture is demonstrated by reproducing theoretical attacks on LoRaWAN 1.0

1:54:05 - GNU Radio implementation for Multiuser Multi-Armed Bandit learning algorithms in IoT networks, Manco Julio [et al.]

Novel access schemes based on multi-armed bandit (MAB) learning approaches has been proposed to support the increasing number of devices in IoT networks. In the present work, a GNU radio framework is implemented to recreate an IoT network where IoT devices embedding MAB algorithms are able to learn the availability of the channel for their packet transmissions to the gateway. It allows to incorporate several IoT users recognized by an identifier (ID), and provides a gateway to handle a large number of IDs as well as the packet collisions among IoT devices. The experimental results show that the introduction of learning mechanism in access schemes can improve the performance of the network.

2:13:33 - Phase noise & digital noise: what is it and why it is important for groundbreaking RF-applications., Bourgeois Pierre-Yves

For more than a decade, digital electronics has a massive impact on about every research field offering flexibility, robustness and reconfigurability.

Marcus Müller Keynote: The GNURadio scheduler and internals

Day Two: Tutorial Session One

00:00:50 - Exploring the Radio-Frequency Spectrum

02:11:00 - GNU Radio Internals (Writing Out of Tree Blocks for GNU Radio)

Day Two: Tutorial Session Two

00:50:00 - Brief Intro to Software Defined Radio from ADI

01:23:00 - Hands-on Workshop: Introduction to ADALM-PLUTO and IIO

1:40:30- Hacking Nordic proprietary protocol with GNU Radio