Hi all,
I was just reading the wiki page about the nanoBTS multi-TRX setup. Two things are not clear to me.
1. What is the purpose of the "RF cable"? Is the TX port of the master BTS looped through the second BTS? Or hase every nanoBTS his own TRX/RX? I am asking because I would like to use a nanoBTS-Booster with the multi-TRX setup and therefore require a combined RF signal.
2. The example example "openbsc.cfg" configures the trx 1 as follows:
timeslot 0 phys_chan_config CCCH+SDCCH4 timeslot 1 phys_chan_config SDCCH8
Is this really needed? My first idea was to configure the second trx to TCH/F only.
Best regards Konrad Meier
Hi,
- What is the purpose of the "RF cable"?
Is the TX port of the master BTS looped through the second BTS? Or hase every nanoBTS his own TRX/RX? I am asking because I would like to use a nanoBTS-Booster with the multi-TRX setup and therefore require a combined RF signal.
I'm not entirely sure, but I think that's just the reference clock ?
But in any case you can use splitter / combiner for both the RX and TX path. You will loose 3dB on the RX path because of the split but that might be ok with you if you have a LNA before hand anyway.
- The example example "openbsc.cfg" configures the trx 1 as follows:
timeslot 0 phys_chan_config CCCH+SDCCH4 timeslot 1 phys_chan_config SDCCH8
No, all TCH should work fine.
Cheers,
Sylvain
On Wed, Apr 13, 2011 at 01:10:54PM +0200, Konrad Meier wrote:
Hi all,
I was just reading the wiki page about the nanoBTS multi-TRX setup. Two things are not clear to me.
- What is the purpose of the "RF cable"?
that is unclear, we don't have documentation on it..
The TIB (timing interface bus) cable is obvious: to synchronize timing. The OML gets routed via the ethernet ports. So I don't really know why they need an extra RF cable...
Is the TX port of the master BTS looped through the second BTS? Or hase every nanoBTS his own TRX/RX?
NO !!! my god, you don't want to kill your BTSs. Tx / Rx is separate like before.
I am asking because I would like to use a nanoBTS-Booster with the multi-TRX setup and therefore require a combined RF signal.
the best idea is to use independent boosters. If you want to run two TRX nanoBTS throguh one amplifier, you need high-grade RF combiner, make sure the amplifier doesn't produce intermodulation, etc. Definitely not something you want to be doing without somebody who has a clue about proper RF setups at those frequencies.
- The example example "openbsc.cfg" configures the trx 1 as follows:
timeslot 0 phys_chan_config CCCH+SDCCH4 timeslot 1 phys_chan_config SDCCH8
Is this really needed? My first idea was to configure the second trx to TCH/F only.
That depends on your network requirements, you can of course have all TCH/F.
-
Harald Welte -
Konrad Meier -
Sylvain Munaut