Power-savvy GSM network (was: gsm322.c Bug Fix Patch)

Alexander Chemeris alexander.chemeris at gmail.com
Fri Feb 3 05:17:09 UTC 2012


Hi Kurtis,

(I'm changing subject to the actual topic of this discussion)

Yes, I quickly looked through your code. Looks like a big hack right
now, but I guess it's meant to be a hack at this point :)

So, your idea is to manipulate Tx power of a BTS to cover only
actually working handsets, if I understand correctly. It's not
possible to do with a normal GSM phone, because phone does not
transmit until it sees a beacon. So you want to create a "wake up BTS"
channel to get around. Am I following your logic correctly?

It does look like an interesting idea if could be done dirt-cheap. But
how do you plan to do paging in this system? I see the only way - to
use the same "wake up channel", but in other direction. So basically
you have a network-specific "default" ARFCN which is used when no
active BTS is in range. All communications are first tried on this
ARFCN and only then on other ones. Right?

On Thu, Feb 2, 2012 at 22:43, Kurtis Heimerl <kheimerl at cs.berkeley.edu> wrote:
> This is part of my thesis work at Cal, yes. Range is not in any way involved.
>
> That's roughly the use case, areas where there are too few users to
> keep a BTS in constant use. Our designs allow the power usage to scale
> with the number of users, rather than sit at a fixed output, as they
> do now. The BTS side is simple; the osmocom side is complicated. We
> have a handset that can wakeup a sleeping tower, or a "wakeup button"
> device which only transmits when a button is pressed. That thing is ~5
> bucks and can probably be attached to the back of a legacy phone in
> case we can't convince a large manufacturer to incorporate our changes
> into the baseband.
>
> Anyhow, the code is online if you're interested in looking at our
> progress (https://github.com/kheimerl). It's nowhere near ready, but
> you're a very knowledgeable guy, and I'd be happy to hear your
> opinions on any of our designs.
>
> On Thu, Feb 2, 2012 at 10:37 AM, Alexander Chemeris
> <alexander.chemeris at gmail.com> wrote:
>> Is it a part of your TIER university work?
>> I wonder about use cases for this.
>>
>> One use case I see is when you have a BTS which is rarely used, like
>> in a desert and you don't want it to work all the time. What use cases
>> do you plan to use it for?
>>
>> On Thu, Feb 2, 2012 at 22:03, Kurtis Heimerl <kheimerl at cs.berkeley.edu> wrote:
>>>
>>> Yeah, and we have that working.
>>>
>>> On Thu, Feb 2, 2012 at 12:56 AM, Alexander Chemeris
>>> <alexander.chemeris at gmail.com> wrote:
>>> > On Thu, Feb 2, 2012 at 12:08, Kurtis Heimerl <kheimerl at cs.berkeley.edu> wrote:
>>> >> I think I looked at that... I'll give you some context.
>>> >>
>>> >> We've modified osmocom to "wakeup" a specific tower at a specific
>>> >> ARFCN.
>>> >
>>> > Interesting. Do you mean you send some packet to a "sleeping" BTS to wake it up?
>>> >
>>> > --
>>> > Regards,
>>> > Alexander Chemeris.
>>
>>
>>
>>
>> --
>> Regards,
>> Alexander Chemeris.



--
Regards,
Alexander Chemeris.




More information about the baseband-devel mailing list