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In actual fact, this demonstration is not breaking any laws (and bears no resemblance to sodomy). There are two GSM bands in the US, 850 and 1900 MHz. Chris P

In actual fact, this demonstration is not breaking any laws (and bears no resemblance to sodomy). There are two GSM bands in the US, 850 and 1900 MHz. Chris Paget, in spite of having a UK domain, lives in the Bay Area. His Android demo used RF hardware operating in the 900 MHz ISM band, which does not require a license provided the transmit power is less than 30 dBm (1W) as per FCC part 15. The maximum transmit power of the USRP hardware is ~23 dBm. Ergo, not illegal. Other posters have made reference to Special Temporary Authority that one can apply for from the FCC in order to legally operate radio experiments in licensed spectrum. A relevant example is the OpenBTS GSM network at Burning Man-- http://openbts.sourceforge.net/FieldTest3/STAGrant.pdf http://openbts.sourceforge.net/FieldTest3/STAGrant.pdf The so-called "GSM guard band" between the DECT cordless phone band and the DCS1800 European GSM band being opened up in Western Europe. Unlicensed low-power GSM installations have in fact been legalized in the Netherlands. This swath of spectrum, 1781.7-1785 MHz paired with 1876.7-1880 MHz, was also auctioned off for cheap to 12 companies in the UK by Ofcom (the British equivalent to the FCC) in 2006. OpenBTS and OpenBSC are complementary but not cooperative (at least not yet) projects. The Base Transceiver Station (BTS) and Base Station Controller (BSC) are different key components in a GSM network. For clarification, see: http://gnuradio.org/redmine/wiki/gnuradio/OpenBTSFAQ#What-is-the-relationship-between-OpenBTS-and-OpenBSC http://gnuradio.org/redmine/wiki/gnuradio/OpenBTSFAQ#What-is... OpenBTS currently supports GSM full rate voice and SMS and allows GSM phone to connect to the telephone network via SIP using Asterisk or FreeSwitch. OpenBSC supports GPRS inasmuch as the commercial BTS (e.g., the ip.access nanoBTS) connected to it supports GPRS.

dedward 16y ago
Forgive my ignorance - if the demo operates in the 900Mhz ISM band, how would any GPS phone be able to connect to it?
- mctavjb9 16y ago
  Almost all GSM phones sold in the past 4-5 years are quad-band phones-- 850 MHz/1900 MHz (US, Canada, a few other places), and 900 MHz/1800 MHz (Europe, Asia, Africa). An iPhone in the US, for instance, connects to AT&T for voice calls on the 850 or 1900 MHz bands, depending on what chunk of spectrum the carrier owns in the caller's particular location. If Joe Caller got on a plane to Europe, the phone might roam onto a GSM900 network. But in the US, part of the 900 MHz European GSM band happens to be allocated to ISM. What people experimenting with OpenBTS in the US tend to do is test with old 900/1800 MHz-only phones that can be procured for a pittance on eBay. That way, they're guaranteed not to connect to AT&T or T-Mobile. As a sidenote, before the GSM carriers started upgrading to 3G networks, most GSM phones didn't actually have GPS chips. Sprint & Verizon (CDMA) phones did, because GPS timing information is a crucial part of the standard (see http://alumni.cs.ucr.edu/~saha/stuff/cdma_gps.htm http://alumni.cs.ucr.edu/~saha/stuff/cdma_gps.htm for gory details).

dedward 16y ago

Forgive my ignorance - if the demo operates in the 900Mhz ISM band, how would any GPS phone be able to connect to it?

mctavjb9 16y ago
Almost all GSM phones sold in the past 4-5 years are quad-band phones-- 850 MHz/1900 MHz (US, Canada, a few other places), and 900 MHz/1800 MHz (Europe, Asia, Africa). An iPhone in the US, for instance, connects to AT&T for voice calls on the 850 or 1900 MHz bands, depending on what chunk of spectrum the carrier owns in the caller's particular location. If Joe Caller got on a plane to Europe, the phone might roam onto a GSM900 network. But in the US, part of the 900 MHz European GSM band happens to be allocated to ISM. What people experimenting with OpenBTS in the US tend to do is test with old 900/1800 MHz-only phones that can be procured for a pittance on eBay. That way, they're guaranteed not to connect to AT&T or T-Mobile. As a sidenote, before the GSM carriers started upgrading to 3G networks, most GSM phones didn't actually have GPS chips. Sprint & Verizon (CDMA) phones did, because GPS timing information is a crucial part of the standard (see http://alumni.cs.ucr.edu/~saha/stuff/cdma_gps.htm http://alumni.cs.ucr.edu/~saha/stuff/cdma_gps.htm for gory details).