24 August 2010

Taking it on the Road

So my garage is full of groceries and in front of Harvind's house there's a 16' moving van loaded up with oversized tents, radio tower segments and jugs of water. It must be time for Burning Man.

So what's new with OpenBTS at Burning Man this year?

First, we are moving into multi-ARFCN systems. Last year, we ran a 3-sector system with 1 ARFCN per sector. This year, we will run two sectors with 3 ARFCNs per sector. So with 33% less equipment and about half as much power, we will double our capacity.

Second, we are using new hardware packaging. This will be our first real-world deployment of our second generation radio. In bench testing so far, this new radio is giving considerably better performance than the old USRP + RFX hardware, and at considerably smaller size, power consumption and cost. The BTS packaging is also more compact than 2009, using a 4U rack-mount chassis similar to the one used in Niue, placed in a weatherproof travel rack recycled from thePfarrkirchen workshop. And we are running a 90' tower instead of a 70' tower, using LMR-600 instead of LMR-400. Those changes should give an effective improvement of about 3 dB in overall performance.

(Harvind running one of the BTS units though its paces with the CMD-57.)

Third, we are hoping to have the air to ourselves. We know that Commnet will not be running a portable site from Frog Pond again. We have heard that they have a fulltime site in Gerlach, but hopeful that the coverage and capacity of that site will be too small to cause a lot of the complications we experienced last year. Here's to hoping. We'll see what happens when we get there.

Fourth, we will actually and deliberately route calls to the outside world. We have not done that before but it will probably make the system a lot more useful. We will, however, time-limit calls to prevent abuses. We will not be routing inbound calls, which will do a lot to preserve the social nature of the event.

We hit the road tomorrow and arrive on the playa at 4:30 & G on Thursday morning. Drop by for a visit if you are in the neighborhood. Just look for the tower.


  1. I am now extremely interested in this hardware that you say is not only smaller and better performing than the USRP but also cheaper.

    Yeah, that's a hint that info would be appreciated. :p

  2. Hi David,

    Nice to have some news about you and the OpenBTS project.

    I read can read you experiment the multi ARFCN. This is really great. Finally, did you figure out if the IMD can respect the spec with this 3 ARFCN configuration ? In the US, I think the spec is not as tough as in Europe. But here, ETSI says spurious emissions must not be above -36dBm/100KHz. I think it recently changed to -25dBm but I am not 100% sure. Anyway, were you able to make some measurements ? Does it pass or will pass the spec ? If yes, can you get this at an acceptable PA efficiency ? If yes, how can you do that ? ;-) Please tell me. I am really interested in this topic as, for a deployment, multi ARFCN would help a lot but I am still worried about this IMD issue.

    Anyway, on the software side, multi ARFCN is still really great. Anyway, good luck for Burning Man 2010.

    Again, thanks a lot for making all this possible.

    Best regards.


  3. Yea David, Lets hear some juicy details on this new SDR of yours...? =)

  4. hello Mr.Burgess,
    I was very much impressed by the OpenBTS software and the concept of SRD. I discussed it with my fellow students, and we would like to try and implement it on experimental basis in our college as an academic project. we request your help with the knowledge on the subject which would be of great help for all of us.

  5. Hey! Amazing stuff you are doing there! Get a 'Flattr-button'on the site/here, so I can support you! :D

  6. WOW this is HUGE. first i'm hearing about it: GSM using VoIP!!

    question: how do you plan on getting high grade T-1 or better lines to the "remote" locations where OpenBTS is most needed (in developing countries etc.)!?

    sort of a chicken and egg question isn't it ?

  7. Found out about it from Springwise, and my question is when will it be available for those of us who are off-the-grid?

    Thing is we've been promised so much before this, SAT was supposed to allow us to have phones without the big networks - yeah, the price is prohibitive too!

    Will check back but it sounds great.

  8. Hi David,

    Are you back ? How was Burning Man this year ?

  9. please post some updates on burning man !

  10. I love it! Can't wait for the conference too, it's going to be great. And I'm 100% with you on the boob sweat. It's just plain unnecessary!

  11. Buring man needs more attention, almost there!