OpenBSC questions

the grugq thegrugq at gmail.com
Sat Feb 20 13:48:57 UTC 2010


Hey,

I think you're confusing the openbsc project with the openbts project.  
Openbsc uses existing BTS hardware to handle the RF and focuses on the  
backend of the BTS interface. OpenBTS uses the USRP (not the USRP2)  
for the RF and is writing a complete stack from the radio layer up.  
They are the project which connects directly with a VoIP PBX and  
handle GSM - SIP.

If you want to work on the OpenBTS project you'll need a USRP (not  
USRP2) and a couple of RF boards. The 900 band seems to best  
supported, so you'll be looking t an outlay of about 1400 USD. You'll  
also need to modify the RF boards before you can use them. It is  
documented across a number of websites. Google is your friend.

Check out the openbts website.

cheers,

--gq

On 20 Feb 2010, at 19:43, Christopher Friedt <chrisfriedt at gmail.com>  
wrote:

> So let me ask a couple of questions about OpenBSC to clarify things  
> for myself.
>
> What are the requirements for running OpenBSC ?
> a) a USRP2
> b) some kind of computer with gigabit ethernet (recommended hardware?
> what kind of load would this be responsible for?)
> b) a broadband internet connection
> c) anything else? Some kind of VOIP account somewhere?
>
> The reason I'm asking is that I've been doing quite a bit of work with
> the USRP2 at university, and have been considering buying one for
> myself for quite some time (although as a student, it's hard to
> justify the price). My professional / academic / hobby interests
> definitely involve hacking mobiles, investigating mobile radio,
> hacking various arm devices, even hardware design, etc, and I guess
> that OpenBSC would be ideal to  for testing out osmocom baseband
> firmware (rather than having a commercial provider's black box for a
> BS).
>
> I guess another question I could pose to the list would be:
>
> Is the USRP2 hardware-capable of supporting something UMTS, EDGE, etc?
> I know that the spec sheets say that it's capable of 50 MHz of
> instantaneous bandwidth, but I believe that the high data rate 3G (and
> further) protocols are using wideband OFDM. From my understanding, I
> would imagine that it would be necessary to support much more than 50
> MHz of instantaneous bandwidth, or somehow be able to load the
> transceiver buffers quickly and sequentially. then push a broad
> spectrum in parallel. Perhaps this can be achieved with a MIMO
> configuration, or with a specialized daughter card.
>
> Any thoughts?
>
> C
>




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