Open Source Spectrum

If you saw the Memepunks article on the Maker Faire and watched the video link, you saw a segment on "Software Radio". When we think of "radio" we don't often appreciate the full breadth of the word. Most people envision AM, FM, XM, or perhaps shortwave. But radio is a great big chunk of the electromagnetic spectrum. It consists of cellular signals, WiFi, broadcast TV, garage door openers, cordless phones, RFIDs, bluetooth, GPS, radar, and a host of other mediums. Historically, we think of all of those devices as very different. Your Dish TV receiver doesn't seem to be a very close relative of your keyless entry fob. However all of these radio devices are in fact cousins. The only reason they are each dedicated to a specific task is because, up until this point, radios weren't all that smart. But this is changing as we speak.

GNU Radio has arrived to free us from the bonds of convention. It is a collaborative project between Matt Ettus and Eric Blossom. Originaly, Eric just wanted something that could Decode HDTV broadcasts, in order to escape the looming vileness of the broadcast flag legislation. What he and Matt have cooked up has turned out to be so much more. The hardware is a Universal Software Radio Peripheral. A mother board with slots for a few daughter cards. The mother board plugs into the USB of your computer, and you can mix and match daughter cards to access different parts of the spectrum. Unlike conventional radio, none of the thinking is hard coded. All of the real work is done via software. Using GNU Radio, you can transform your WiFi access point into an HDTV receiver simply by running a different program.

A few lines of open source code, and a fast enough processor, and the USRP can assume any function, from transceiving GPS to listening to every FM band, or police radio. This miraculous device is not just a jack of all trades, but a master of them as well. With the proper software algorithms, you can turn a USRP into an HDTV receiver even more perfect than a dedicated off the shelf model. And speaking of off the shelf, Matt Ettus is now building and selling Universal Software Radio Peripherals. And of course, using the GNU public license, all of the software is open source. Giving you the freedom to tinker with the electromagnetic spectrum until your heart is content. The price for the hardware may be a bit prohibitive for the garage tinkerer, but a USRP costs about a tenth of what a less functional close source hardware platform would.

The uses for something like this are limitless. Perhaps you want to record every FM broadcast for a day. Or have your hot spot give off both WiFi and 3G. More important are the applications that aren't obvious, the things will only come from a decentralized and unregulated spectrum. Eric Blossom says, "Decentralized controls enable innovation at the edge -- it's closer to the computer model, I think what we'll find is that people will come up with things we never really thought about." Take for instance Path Intelligence, which uses GNU Radio to anonymously track the presence of cell phones, and thus foot traffic in UK malls for marketing purposes. More daughter cards, antennas and software apps are being developed for the USRP everyday. Soon you'll just have a black box that plugs into your computer, that does anything and everything that can be done with the spectrum. If you want to broadcast HD from your laptop, run a program. Want to get on the WiMax bandwagon? Run another.

Finally a use for all of those unused PCI or PCMCIA slots. This hearkens back to the days of ham radio, but with a wellspring of more possibilities. Eric is already working on a radar system that will use signals from cell towers, and commercial broadcast towers to locate and map flying objects up to 50 miles away. And there is no need to just use one slice of the spectrum at any given time. There is nothing to stop you from transmitting data over WiFi while broadcasting in HD. Matt Ettus believes his device could change the world. From the narrow bandwidth, false scarcity world of dumb electronics, to something quite different... "A world in which bandwidth is not an issue. People will create applications that will use that bandwidth, like complete telepresence." Complete telepresence, an end to bandwidth scarcity, and Open Source to boot. I'm not sure whether or not video really did kill the radio star. But GNU Radio is set to bury them both. [via Wired]


"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." - Albert Einstein