Cool! I just got a talk for the Software Defined Radio Academy at HAMRADIO accepted. HAMRADIO is a rather large annual amateur radio exhibition at Friedrichshafen in Germany. Since more and more hams are interested in Software Defined Radio (SDR), there will be a sub-conference about SDR this year — the Software Defined Radio Academy.

According to my understanding, the idea is to have a mix of introductory and hands-on lesson as well as some more research oriented talks. I applied for a talk about reverse engineering digital wireless signals. Following is the abstract I submitted when applying for the talk.

Reverse Engineering Digital Signals by Example

In this talk we will go through the complete process of reverse engineering an unknown digital signal. Although a widespread car key fob from Hella will serve as an example, the aim is to provide a generally applicable walk-through. To decode the signal we will use different tools to determine its frequency, modulation, encoding, and finally its frame format. More specifically, we will use fosphor, baudline, gqrx, and audacity to study the signal in time and frequency domain. Even though we will just have a quick glance at the different applications, the goal is to show their capabilities and more importantly how they can be combined.

Once we figured out the waveform and its parameters, we will go ahead an build a receiver in GNU Radio. GNU Radio is a real-time signal processing framework that already provides all means to demodulate the signal and produce a bit stream. At this point we will use command line tools and simple python scripts to study the bit stream to derive the frame format. Finally, we add a small technology specific block to GNU Radio that decodes and parses the frames to build a complete receiver. Hopefully, this will provide some hands-on experience and give an overview over the various tools that are available to study and decode the signals out there.

See you at HAMRADIO’15!