17.05.2012 14:32 пользователь "Kalle Pietila" kalle.pietila@gmail.com написал:
Hi Alexander,
yes I'm aware that a BTS would need to be transmitting all time, which is not best starting point for being power-efficient. However good to get confirmation that multi-ARFCN can be avoided. I mailed to BB list as I see this part as most probable technical show stopper for this initiative. The chip designs seem to be targeted for mobile broandband applications with all that unnecessary functionality at a silicon screaming for more power. Also proprietary L1 can be a major problem when cost of BTS module needs to be kept minimal (modules getting lost, damaged, stolen, or vandalized) and also this stuff would need to be affordably available for the developers. Actually, SMS-only supporting base-stations could be a first viable application for an open L1 implementation?
OpenBTS already has an open-source implementation of a base station.
We're though about balloon raising the antenna up and also flying drones with BTS as payload. Flying or floating might work well on still weather, but probably not at all under heavy winds. Not sure whether this would acceptable shortcoming for the imaginary "customer". Balloon-approach might just have worked better in case Haiti, I see the point.
To get a reasonable coverage you have to elevate your antenna as high as possible. So "dropping" it's not an option anyway, imho. You need a manual labor to install this antennas.
Thanks for hinting the OpenBTS mailing list, I'll drop a line there too.
Best Wishes,
Kalle Pietilä
On Thu, May 17, 2012 at 10:17 AM, Alexander Chemeris alexander.chemeris@gmail.com wrote:
Hi Kalle,
BTS has to transmit constantly on it's main ARFCN, no matter do you make calls or just send SMS. So while you operate a single ARFCN you can't save power by employing only SMS. On the other hand, for SMS a single ARFCN would be enough to provide a good capacity, while support for calls would require a multi-ARFCN config which would be quite power hungry.
Have you thought about using a balloon for carrying a BTS instead of dropping to a ground? This would give you much better coverage easily then on-the-ground installation.
PS I think this would get more responses from the OpenBTS mailing list, then from OsmocomBB mailing list, as this is definitely a network-side question.
On Wed, May 16, 2012 at 10:28 PM, Kalle Pietila kalle.pietila@gmail.com
wrote:
Dear baseband enthusiasts,
on SMOS project we had this crazy idea for catastrophe communications in which cellular base stations would be miniaturized enough to be airdropped into disaster zones. We felt that this might be possible if all functionality except SMS was stripped from the base stations (hence SMOS, SMS Our Souls). Most ideally such technology would come in near cellphone size (excluding batteries), something like osmocom's earlier "Phone acting as BTS" hackwork.
We did not have the guts nor skills to start doing this by ourselves, so we just published our findings and studies under Creative Commons BY license. As we wish to keep this idea open to everyone, our web-documentation would benefit on this regard from some more in-depth HW-related analysis and suggestions (our team fell short on this area). Once it's all published, it cannot be patented. I personally see some humanitarian & karma-improving angle in doing it this way. Helping human kinds in disaster should not be bound by patent laws.
So I'm asking for constructive criticism and also offering possibility to write some informal blogs about your views on www.zygomatica.com/smos (with our team's editorial support) . At the same time it should be noted that such technically oriented blog writings at my friends' site zygomatica.com would likely reach 50 readers at most. To put it more nicely, reaching the widest possible audience is not our focus here anyways.
My technical vision is presented at
http://www.zygomatica.com/wp-content/uploads/2012/04/SMOS6-Technical-goals-S...
.. and the full list of formal documents at end of http://www.zygomatica.com/smos/ . The other provided background material might be even more valuable to those that start considering this idea more seriously.
So, For instance, can stripping down the functionality just to supporting SMS delivery bring down the power consumption in any significant manner?
Thanks and regards,
Kalle Pietilä
P.S. Mailed to this list as suggested by Harald.
-- Regards, Alexander Chemeris. CEO, Fairwaves LLC / ООО УмРадио http://fairwaves.ru