multitrx with osmotrx

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Tom Tsou tom at tsou.cc
Thu Jun 16 17:10:50 UTC 2016


On Thu, Jun 16, 2016 at 8:21 AM, Pierre Baudry
<pierre.baudry at diateam.net> wrote:
> On 16/06/2016 17:00, Max wrote:
>> I've noticed check for device type around
>> Transceiver52M/UHDDevice.cpp:772 - seems like USRP B200 is not supported
>> for multitrx configurations:
>> sudo chrt 20 ./Transceiver52M/osmo-trx -c 2
>> sudo chrt 15 ./src/osmo-bts-trx/osmo-bts-trx -c
>> ~/.config/osmocom/osmo-bts-trx.cfg -i 192.168.122.1 -t 2
>>
>> Where does this limitation comes from? Is it just smth which is not
>> implemented (yet) or it's impossible to implement due to X and Y?

B200 is a single RF channel device.

> However, you could try Thomas's work on multi-arfcn transceiver which
> can be found here: https://github.com/ttsou/osmo-trx/tree/mcbts

Now that GPRS is working with osmo-bts-trx and osmo-trx, I will begin
merging the multi-carrier transceiver chain in the coming week.

The history is that multi-arfcn was initially developed on the single
channel USRP2. In later devices, such as the UmTRX and B210, there
were advantages in both simplicity and RF performance from separate
discrete channels, and that became the preferred multi-channel
approach used for later testing.

There are still, however, benefits (i.e. cost and higher capacity
support) to the multi-carrier approach on a single physical RF channel
that make it worthwhile to support in mainline.

  -TT



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