multiple phy with osmo-trx

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Max msuraev at sysmocom.de
Thu Oct 13 14:34:54 UTC 2016


Hi.

After updating uhd to UHD_003.010.000.000-release I got it partially
working. It's summarized in https://projects.osmocom.org/issues/1648

If I understood correctly there are 2 possibilities for multi-trx setup
with osmo-trx: multiplexed and non-multiplexed. The command to run
osmo-bts-trx is the same in both cases: you've got to specify number of
trx like in "./src/osmo-bts-trx/osmo-bts-trx -c
~/.config/osmocom/osmo-bts-mtrx.cfg -t 2". From osmo-trx, the difference is:

non-multiplexed: ./Transceiver52M/osmo-trx -c 2 -l INFO

multiplexed: ./Transceiver52M/osmo-trx -m -c 2 -l INFO

The question is - is there any difference between multiplexed and
non-multiplexed mode for osmo-bts-trx config file? I've got multiplexed
mode working with following setup:

...

phy 0
 instance 0
 instance 1
...

 trx 0
  phy 0 instance 0
 trx 1
  phy 0 instance 1
...

Should it look differently for non-multiplexed mode? Are there some
other command-line options or config files adjustments missing to make
non-multiplexed mode working? Did I got the overall setup right?


On 08/12/2016 09:05 PM, Tom Tsou wrote:
> On Thu, Aug 11, 2016 at 2:50 AM, Max <msuraev at sysmocom.de> wrote:
>> On 08/10/2016 07:35 PM, Tom Tsou wrote:
>>> The 'multi-carrier' approach multiplexes up to 3 ARFCN channels onto a
>>> single physical RF channel (side A) on the B210. Channel spacing is
>>> fixed at 800 kHz, or 4 ARFCN channels. ARFCN settings from OpenBSC
>>> must match accordingly. The '-m' option enables this configuration.
>> Could you give an example of necessary openbsc and osmo-bts
>> configuration for both cases?
> Config files and README are attached. Note that the osmo-trx
> multi-carrier '-m' option requires UHD master. I'm still backporting
> the needed settings.
>
>>> Also note that the above configurations cannot be combined.
>> So I should not run "./Transceiver52M/osmo-trx -c 2 -g -m"?
>> Only "./Transceiver52M/osmo-trx -c 2 -g" or "./Transceiver52M/osmo-trx
>> -g -m"?
>> Or you referring to the incompatibility of configuration of openbsc? Or
>> Osmobts?
> You cannot support, for example, 6 ARFCN operation on B210 using 3 TRX
> on side A and another 3 TRX on side B.
>
> Whether you use '-c 2 -m' or just '-c 2' depends on whether you want
> to feed two ARFCN channels through 1 or 2 PA's respectively.
>
>   -TT

-- 
Max Suraev <msuraev at sysmocom.de> http://www.sysmocom.de/
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