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European GNU Radio Days Programme Day 1: 24.06.2022
13:00 - 14:30 The Mobile Fading Channel and Orthogonal Frequency-Division Multiplexing (OFDM) - 3 Tutorials
Mobile fading channels are subject to multipath propagation and the Doppler effect. These two physical effects result in frequency and time selectivities which have a devastating impact on the transmitted digital communication signal. Concerning frequency selectivity, the most widely used technique in practice is OFDM where the transmitted bandwidth is divided in several sub-carriers which are independent from each other. With the use of adequate channel estimation techniques and error correcting codes, OFDM has proved to be a very robust solution on mobile fading channels.
The goal of these 3 tutorials is therefore to give the audience the key elements to be able to understand the behaviour of mobile fading channels and the OFDM technique including the design of a practical system with the help of the GNU Radio framework.
14:45 - 16:45 Free, opensource Field Programmable Gate Array (FPGA) development frameworks for radiofrequency communication
FPGA have become ubiquitous in Software Defined Radio signal generation thanks to their ability to stream continuous flow of data at several tens to hundreds of megasamples/s. However, most FPGA manufacturers still lock the user with proprietary development software either plagued with the limited flexibility of Hardware Description Languages or the poor suitability of High Level-language Synthesis to continuous stream generation. With the advent of free, opensource synthesizers, users become free from a given FPGA manufacturer, in addition to being given access to higher abstraction levels of hardware description.
In this tutorial, we will focus on implementing signal processing chains for radiofrequency signal generation, assessing the various means of generating a radiofrequency carrier on an FPGA and modulating using various schemes benefitting at best from the full complex description of the signal. Practical demonstrations will involve commercial, off the shelf hardware with as few external components as possible.
GNU Radio is a set of toolboxes for developing custom processing chains and, when needed, custom additional processing blocks. We will demonstrate in this tutorial how to benefit from existing functionalities of GNU Radio for digital signal communication.
Software Defined Radio Academy Programme Day 2: 25.06.2022
10:00 - 10:15 Prof. Dr. Michael Hartje DK5HH, Markus Heller, M.A., DL8RDS: Welcome and Introduction
10:15 - 10:45 Prof. Dr. Harald Gerlach DL2SAX: SDR im Contest: Anwendungen eines SDRs im Contest
Since a few years the were SDR-TRX available and of course they are used also in contests. The main talks in the SDR-academie has a technical aim. The following lecture about „SDR in contest“ is from the sight of a user and avantage of using them in contests. The talk will give you a few hints about possibilities and additional benefits you can have with a SDR-Transceiver in a contest.
10:45 - 11:15 Oleg Kutkov (Ukraine): HackRF Supercluster
HackRF supercluster - a crazy way to build a wideband SDR receiver: To monitor and analyze the wider RF bands, I decided to build something new with the cheap components that I already have. This was the beginning of the way that end up in the creation of lots of the additional hardware, and software. I learned a lot of new things along the way and would like to share my experience.
11:15 - 11:45 Wojciech Kaczmarski SP5WWP, Niccolò Izzo IU2KIN: M17 Project - new digital voice mode for VHF and up
M17 team is developing a new digital radio protocol for data and voice, made by and for amateur radio operators. The protocol's voice mode uses the free and open Codec 2 voice encoder. This means there are no patents, no royalties, and no licensing. This freedom to build, understand, and innovate is core to amateur radio, but has been missing from the commercially available digital voice modes. M17 is unlocking the capabilities that amateur radio hardware should already have. Started in Poland back in 2019, the project now embraces a vast community of radio operators from the whole world.
11:45 - 12:00 (Lunch Break)
12:00 - 12:30 IARU President Sylvain Azarian F4GKR and Ulrich L. Rohde Award Committee: Ulrich L. Rohde Award Ceremony
12:30 - 13:15 Dr. János Selmeczi HA5FT: PLLs in Software Defined Radios
There are a lot of use of PLLs in SDRs. In most cases they are used in implementing modulation or demodulation of digital data. We could find PLLs fully implemented in software and mixed type of PLLs which have analog and software parts as well. This presentation will deal with PLLs implemented in software. The presentation first will review the theoretical background necessary to understand the behaviors of the PLLs followed by the description of the most commonly used algorithm and finally present an python framework which could be used for experimenting with the various algorithms. The presentation of the algorithms will cover the carrier and bit synchronizations, the frequency locked loops (FLLs), the dynamic bandwidth control and the lock detection in low SNR conditions. I will present not only a high level view of the algorithms but will provide the description of the most important parts of the algorithms like phase detector, loop filter, gated integrator, etc. The python framework is open sourced and published on github. You could use it to experiment with the presented algorithm and to develop your own algorithms as well. Most of the algorithms are from real life project and had been implemented in FPGA firmware. They could be easily implemented in c language applications as well.
13:15 - 13:45 Laurence Barker G8NJJ: ARM Processor to Xilinx FPGA Connection for SDR
This presentation describes the interfaces available and work required to support high speed data transfer between Xilinx FPGA and ARM processors for SDR. Zynq FPGAs have both parallel bus interfaces and AXI streams available; other FPGAs can use PCI Express or possibly SPI. Challenges include memory management, cacheing and Linux device drivers. The presentation covers the design decisions made for the "Saturn" SDR with Artix-7 FPGA and Raspberry Pi 4 Compute Module processor, the data rates achieved through various routes and the challenges that had to be overcome. We hope, if all goes well, to show a working Saturn board.
13:45 - 14:15 Prof. Dr. Alberto Dassatti, Dr. Roberto Rigamonti, Oscar Rodriguez Zaloña MSc: User-Assisted Spectrum Labeling System with Automated Baud Rate Estimation
While modern Software Defined Radios allow low-cost access to large portions of the spectrum, deciphering what these waves carry still goes beyond the capabilities of individuals and small organizations. This is largely due to the huge human and monetary investments required to build reliable signal datasets for automated discovery and reasoning.
In this paper we introduce SpectroGrasp, a software that eases the labour-intensive, tedious and error prone task of signal labeling. Besides its Graphical User Interface that allows signal exploration, it incorporates an innovative baud rate estimator that proved to be very effective on single-carrier signals derived from a dataset of recordings from a signal generator.
The software, which is at an advanced prototype stage, will be made publicly available under an open license, and we welcome collaborations to further develop it.
14:15 - 14:45 Thomas Boegl DL9MD: The perfect HF Receiver. How would it look like today?
Modern HF Receivers must fulfill a variety of requirements e.g. sensitivity, robustness and many others. Key requirements are often directly leading to RF concepts and architectures with their specific advantages and disadvantages. But how would the perfect HF receiver look like today which combines all available technologies into a most modern concept for a software defined receiver approach? Is it “IF-Sampling” or “Direct Sampling” or even something else?
14:45 - 15:15 Dr. Bastian Blössl DF1BBL: FutureSDR: An Async SDR Runtime for Heterogeneous Architectures
This talk introduces FutureSDR, an experimental async SDR runtime for heterogeneous architectures. While it is primarily a research platform to experiment with novel concepts, it has unique features that can make it a good choice for challenging SDR applications. Its main advantage is heterogeneity in three domains: the architecture (x86, ARM, RISC-V, WebAssembly), the platform (Linux, Windows, macOS, Android, the browser), and the compute (CPU, Vulkan GPU, Xilinx Zynq DMA, and WebGPU for GPU acceleration in the browser). Relying on an async runtime, it, furthermore, allows plugging in custom schedulers, optimized for your architecture, application, or requirements. In the talk, we will introduce the core concepts, show how they help to overcome long-standing issues of existing frameworks, and present example applications that are enabled by FutureSDR.
15:15 - 15:30 (coffee break)
15:30 - 16:00 Dr. Henning Paul DC4HP: Building a Tx capable SDR from used Bitcoin mining controllers
This talk is a follow-up to my 2021 talk on building a homebrew Rx SDR based on Xilinx Zynq technology. In this talk, I will present how a decommissioned Bitcoin mining controller purchased on AliExpress for $15 can be repurposed into a Tx capable SDR. It is is presented how a high-speed DAC add-on board was designed and how it is interfaced to a QRP amplifier derived from the Hermes-Lite project. Furthermore, the signal processing in GNU Radio is explained and how this software-based transmitter can be interfaced to existing tools like WSJT-X using a self-written Python daemon that implements a CAT interface.
16:00 - 16:30 Dr. Henning Paul DC4HP: Modifying the ADALM-PLUTO for MIMO experiments
The well-known ADALM-PLUTO by Analog Devices is an affordable SDR that is not only capable of full-duplex operation, but can also be modified to allow 2x2 MIMO operation, i.e., enable 2 Rx and Tx paths each. This talk will present the required hardware modifications and the interfacing in GNU Radio and will sketch the rough concept of a 13cm Doppler radar based on this platform as an example.
16:30 - 17:00 Evariste Courjaud F5OEO: Experience on PlutoSDR and firmware, DATV and some tricks in FPGA
This talk shares my 3 years experience developing on plutosdr platform. Goal is to use the singularity of the hardware by focusing on the embedded side : firmware building. FPGA custom design for offloading dsp processing (FFT spectrum, conversion of I/Q samples , DVBS2 modulator). Linux drivers for extended capabilities (recognized as an audio card, gps , audio and video drivers, extended frequency down to 47Mhz). Some embedded softwares like wide band spectrum, recording spectrum with gps positioning, MQTT control, DVBS2 modulator.
17:00 - 17:30 Adrian Musceac YO8RZZ: Implementation of a DMR base station using MMDVM, GNU Radio and LimeSDR devices
Digital Mobile Radio is a land-mobile voice and data communications radio standard which implements a double timeslot time division multiple access scheme (TDMA).
A DMR base station capable of transmitting and receiving voice transmissions on both timeslots was implemented in software using the multi-mode digital voice modem (MMDVM) project, GNU Radio flowgraphs implemented in the SDR application QRadioLink and a LimeNET-Micro SDR transceiver.
17:30 - 18:00 Prof. Dr. Michael Hartje DK5HH, Markus Heller, M.A., DL8RDS: Final Discussion
The YouTube stream is available at: https://youtube.sdra.io