Tom Rondeau

An overview of the DARPA Bay Area SDR Hackfest (darpahackfest.com).

In November of 2017, the United States Defense Advanced Research Projects Agency (DARPA) held its first large-scale Hackfest. The DARPA Bay Area SDR Hackfest focused on using software defined radio (SDR) to control unmanned aerial vehicles (UAV), otherwise known as drones. The week-long Hackfest involved a set of Missions that were tackled by eight teams selected earlier in the year, a series of speakers to give two talks per day, and an open Hacker Space to allow anyone who wanted room to hack, explore, and work on projects.

DARPA created this event to explore a number of questions. First, who else is working in the field of SDR and UAVs that might be able to contribute to the DARPA mission? What new ideas and innovations might prove significant to the future of SDR and UAV technology in the future? And how does free and open source software (FOSS) enable talented engineers and scientists to answer hard technical challenges quickly? The event produced interesting results, and in this talk, we will examine what came out of the Hackfest and think about the future purposes of these kinds of events and ways of engaging the developer communities.

The state of SDR, and free/open SDR in particular, is interesting. In some cases, SDR research and progress has been declared dead, implying that there is nothing left to research or develop. Practical usage of SDR tells a different story, though, and users of SDR products run into all sorts of issues every day.

In this panel, we would like to discuss with the audience what the top issues are that SDR frameworks need to solve in the near future -- be they technical, legal, political or anything else.

What are the top 3 items that the realm of Software Defined Radio needs to figure out? In this panel, we invite some experts as well as the entire audience to discuss this question. We shall discuss technical challenges (if there are any) as well as legal and political challenges. Does free/open software radio have any different questions to tackle? If we were to attend a technical conference in the near future, what would be the most mind-blowing thing we could present? Will there be more, competing frameworks going forward, or will they consolidate? These and many more questions shall be the topic of this year's SDR panel.

The Defense Advanced Research Projects Agency (DARPA) is hosting a pre-FOSDEM hackfest on unintentional emitters of electromagnetic signals. The hackfest should attract many people from the software defined radio (SDR) community to participate as it will involve the design and development of techniques to discover, capture, identify, and disseminate the emissions and emitters. The hackfest will take place in Brussels from February 1 – 3, so this talk will provide a review of the work that went on in the days just preceding FOSDEM.

Electromagnetic (EM) emissions are everywhere and come from radio systems that purposefully emit EM signals, unintended emissions from these radios in other frequencies, and unintentional emissions from all of our electronics, even those not designed as radios. These emissions affect spectrum usage, which is a vital part of our daily lives and continues to grow in its importance. As more services and devices are depending on wireless connectivity, the problems of interference will grow, too. We typically think about interference coming from other wireless devices, but other electronics create EM emissions as well, such as computers and vehicles. But even more mundane electronics, like AC-to-DC converter “wall-warts” for charging cell phones, produce emissions. Though often low-power, the growing prevalence of electronics to support our daily lives is also an additive source of interference.

DARPA will be hosting a hackfest in Brussels over the three days leading up to FOSDEM. The purpose of the hackfest on unintentional emitters is to help us develop techniques to find and study the emissions with the hope of better understanding and characterizing how different devices behave. The hackfest outcomes could lead to important scientific and technical knowledge for how we understand the interference problems from these emitters. Can we characterize how a building and its various components look by its EM emissions? How about parts of a city and the effects of traffic, subways, and other infrastructure?

The FOSDEM presentation will review the work that went on during the three-day hackfest and report on any resulting techniques/technology and what we learned about the unintentional emissions around us. It will be a relatively short talk presented without slides as a quick wrap-up to the FOSDEM SDR audience.

SDR projects have come a long way, and allow users to do all sorts of things, ranging from telecoms services (e.g. setting up a base station) to all kinds of scientific purposes (radio astronomy, DSP, etc.).

In this panel, we want to bring together leaders from various projects as well as community members, and discuss the future of free SDR, and identify possible areas of collaboration.

As SDR communities, we will discuss these topics (among others):

• What are the near- and long-term goals for free SDR projects?
• How can we collaborate?
• Have we missed areas where we could use more action (between GNU Radio and the others we have the scientific stuff and the telecoms stuff sorted out, but what else is there)?
• Which communities do we want to engage with?

We invite project leaders, but also all community members to join us for this discussion.

In GNU Radio, we often find ourselves going to the FM broadcast stations as a first introduction to radio, software radio, and signal processing. FM broadcast is nearly ubiquitous and has a narrow enough bandwidth that very inexpensive hardware all over the world can work with it. It also has an interesting enough structure that allows us to go from simple to more complicated GNU Radio applications for studying all sorts of ways in which we can process it as a signal.

FM broadcasting is present almost anywhere in the world, and its structure makes it an interesting challenge and good learning exercise for developing GNU Radio applications. Likewise, almost any software radio RF front end is capable of processing FM: from the very cheap RTL-SDR dongles to the more expensive USRPs. In this talk, I will introduce FM from its historical roots and walk through why it is a technologically important development as I build more complicated GNU Radio applications to explore the FM waveform. As a broadcast medium, FM has also played an important political, social, and cultural role in the last century. Aside from the technical development of how to process FM signals, I will use this lecture as an introduction to regulatory agencies and band planning. Part of this will involve the development, problems, and importance of FM pirate radio. The lecture will involve a demonstration of embedded GNU Radio applications that will showcase the FM capture effect by imitating a (very) low power radio station.

GNU Radio is an expansive ecosystem of libraries, hardware interfaces, third-party applications, and community members of all types. With all of these parts, we know it's difficult to understand where to begin. In this lecture, I will provide an overview of the ecosystem and walk through a set of examples that use GNU Radio to explore the wireless space.

Given the huge range of capabilities, available tools, library of third-party applications, and size of the community, this lecture covers a basic introduction to GNU Radio. We will explore, through some historical context, the use of GNU Radio to build some simple applications. Although simple, a key to using GNU Radio is through exploration of the tools and available features, and so the introductory material is meant to overcome the basic difficulties of just getting to know what GNU Radio is and what it can do. With this knowledge that provides an exposure to the library, webpages, tools, and community, we think that other users can continue to explore the space of capabilities and applications for much more advanced features.

Although GNU Radio is now over ten years old, the project has recently seen an incredible amount of growth in features. The capabilities we have been adding to the project are focused on improving current signal handling techniques, extending the GNU Radio project's ability to handle newer and developing digital wireless signals, and focusing more on the embedded systems world.

In this talk, we will go over the basics of GNU Radio and a list of some of the newer features. We will then explore a few ways of interacting with GNU Radio to explore the wireless spectrum and signal processing techniques. To do this, we will look at how we use concepts of GUI instruments and interactions, stream tags and messages, and ControlPort for monitoring and controlling GNU Radio applications.