Notes from Eric Blossom and Matt Ettus's talk on GNU Radio O'Reilly Emerging Technology Conference 2003 Cory Doctorow doctorow@craphound.com -- GNU Radio is a free software toolkit for realtime signal processing things -- radio included. Works for sonar, medical imaging, etc. Get as much stuff as we can into software, out of hardware. Turn all the hardware problems into software problems -- all wave forms are encoded, decoded, modulated and demodded in software. What can you do with it? * Conventional radio * Spectrum monitoring * Multichannel -- one app sucks down the whole RF spectrum; AT&T could support all its legacy phones (GSM, CDMA, Analog) on one tower, without any forklift upgrade. * Morph mode * Morph on the fly -- a device that reconfigures itself for what you need, sat phone, cell phone, pager, etc, your 802.11b could talk 802.11g once it's invented * Better spectrum utilization -- listen-before-talk, then choose an unused band. Accommodates legacy users and lets you move forward. * Cognitive radio -- minimal power, shaped xmission, etc -- How do you build a GNU Radio? Narrowband comms (emergency signals) can be handled by ADC on a sound-card, with an RF down/up-converter Wideband systems require faster, more capable samplers. We're using a 20Mcycles/second -- gives you 10MHz of bandwidth. All of cellular, TV, FM can work with this, but not WiFi. The key piece is the ADC and the DAC. Up and down converters aren't trivial, but lots of people know how to make them. We can receive any 6MHz in the 50-900MHz range -- Demo: Spectrum sample Shows 10MHz at 90Mhz -- an FM radio signal If you buy th echeapest computer you can buy, it's fast enough for this: 1GHz P3, i.e. An entire GSM channel in 1% of a P3. This is a 1.5GHz Athlan We're shipping an open DAC, open hardware and an open, recongifurable FPGA which will do 60Msamples/sec -- Demo HTDV receive in GNU radio 6MHz wide, 18MHz signal Scene from "Law and Order" plays, full-resolution HD. Skips a commercial. 1080i signal rendered at 10x7 for the monitor I described this to the CPTWG and told them I was building it. -- Politics: * MPAA/CTPWG/BPDG "Broadcast Flag" -- TV people get free spectrum from the public and in exchange they don't get to encrypt. HDTV is being broadcast nearly everywhere now, but the DTV transition is still slow. You can spool the MPEG 2 streams to disk. Build a super-TiVo. Perfect commercial ripping -- in a network environment, only one person has to mark it. This would be illegal under the Broadcast Flag. They want to increase security by putting all the good stuff in Ring Zero, which compromises everything. They're also doing the ARDG. All high-sppeed ADC would have to detect watermarks. * FCC: Software radio in general * FCC: Free software radio -- We've got an ATSC xmitter, too. What is interference? Ripples in a pond will cross each other without interfering. Cool meshnet research: the capacity of the network increases with the number of smart transmitters. Our apps consume more MIPS than any other apps -- Intel and AMD love them as benchmarkers. Is is field-reprogrammable hardware -- like an FPGA, but for radio. We can do phased-array antennae