Spectrum Wars

25.07.2015 14:42

SpectrumWars will be a programming game where players compete for bandwidth on a limited piece of radio spectrum. It's also apparently a title that tends to draw attention from bored conference attendees and European commissioners alike.

SpectrumWars XKCD spoof.

with apologies to Randall Munroe

With the CREW project nearing completion, it was decided that one of the last things created in the project will be a game. This might seem an odd conclusion to five years of work from 8 European institutions that previously included little in terms of what most would consider entertainment. We built testing environments for experimentation with modern wireless communications aimed at the exclusive club of people that know what CSMA/CA and PCFICH stand for. In the end, I'm not sure we managed to convince them that what we did was useful to their efforts. Much less I guess the broader public and potential students that would like to study this field.

What better to correct this than to present the need for smart radio testbeds in the form of a fun game? The end of the project is also the time when you want to show off your work in way that reaches the broadest possible audience. Everything to raise the possibility that powers-that-be grant you funding for another project.

In any case, SpectrumWars is a fun little thing to work on and I gladly picked it up in the general lethargy that typically suffuses European projects on their home stretch. The idea stems from a combination of the venerable RobotWar game concept, DARPA Spectrum Challenge and some previous demonstrations by the CREW project at various conferences. Instead of writing a program for a robot that fights off other robots, players program radios. Turning the turret becomes tuning the radio to a desired frequency. A spectrum analyzer replaces the radar and the battle arena is a few MHz of vacant spectrum. Whoever manages to be best at transferring data from their transmitter to their receiver in the presence of competition, wins.

A desk-top setup for SpectrumWars with VESNA sensor nodes.

In contrast to the dueling robots, the radios are not simulated: their transmissions happen in the real world and might share the spectrum with Wi-Fi and the broken microwave next door. To keep it fun, things are simplified, of course. The game abstracts the control of the radios to the bare minimum so that a basic player fits into 10 lines of code, and a pretty sophisticated one into 50. This is not the DARPA Challenge where you need a whole team to have a go (unfortunately, there's no five-figure prize fund either).

So far I've made a hardware-agnostic game controller implementation in Python that takes care of all the dirty little details of running the game and defines the player's interface. The radios are VESNA nodes with Texas Instruments CC2500 transceivers and special firmware, but other CREW partners are currently working on supporting their own hardware. A USRP is used as a spectrum sensor that is shared by all users. While a lot of things are still missing (a user-friendly front-end in particular), it was enough to confirm so far that playing with the algorithms in this way is indeed fun (well, at least for my limited idea of fun).

I gave some more details in a talk I had at the Institute last Friday (slides), or you can go check the draft documentation I wrote or the source, if you feel particularly adventurous.

Title slide from the SpectrumWars talk.

In the end, SpectrumWars is supposed to look like a web site where tournaments between algorithms are continuously performed, where one can submit an entry and where a kind of a scoreboard is held. I'm not optimistic that it will be in fact finished to the point where it will be presentable to the general public in the couple of months left for the project. However I think it would be a shame if it went directly into the bit bucket together with many other things when the project funding runs out.

While the future might be uncertain at the moment, I do have a tentative plan to maybe set up an instance of SpectrumWars at the CCC congress in December. The inherently crowded 2.4 GHz spectrum there would certainly present an interesting challenge for the players and the congress does have a history of unusual programming games.

Posted by Tomaž | Categories: Life

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