Re: [Openbts-discuss] Noob Question about multiple ARFCN

[Tom T. <to...@ts...>]

On Sat, Feb 21, 2015 at 5:28 AM, Arthur Rabaté <art...@gm...> wrote:
> That I did understand, with up to 56Mhz of simultaneous bandwidth on both tx
> and rx, we can have a lot of arcfns !!
> Only processing and usb limitation can occur, but that will not be an issue
> with 2 - 3 Mhz of signal.

Yes, a large number of carriers through a single radio unit is
possible, though the RF characteristics become more complicated than
the single ARFCN case. One issue that starts to appear with multiple
carriers is that the PA requirements change from non-linear to linear.

> Is there an old "proof of concept" version of osmotrx supporting this ? and
> if so can we try it out ?
> I have not been coding anything for a while, but I would try to work on it
> in order to get something up and running.

An old version based on the 2.8 release of OpenBTS can be found here,
which is setup for a 100 MHz clocked device such as the N200. Note
that many changes from this branch were merged into mainline OsmoTRX
and OpenBTS - namely the SSE filters, resampler, and type converters -
but the actual synthesis-channelizer components were not.

https://github.com/ttsou/openbts-multi-arfcn

I don't recommend trying to test this branch since version 2.8 is
quite out-of-date, but you can view the large amount of code changes,
some of which were quite dramatic.

  -TT