Hi Harald,
On Tue, Jun 21, 2016 at 11:51 AM, Harald Welte laforge@gnumonks.org wrote:
The first part is to introduce a reasonable BER limit fo 17% for RACH ghost elimination, but I have more plans for unifying the measurement processing/generation accross all supported BTS models.
For osmo-bts-{sysmo,lc15,octphy} it is clear to me how to get the related information on RSSI, BER and LinkQuality for each of the RACH and DATA indications from the PHY.
However, how can I get the related information from osmo-bts-trx?
osmo-bts-trx seems to lack any BER reporting toward the common part, which among other things is the reason why link/rate adaption in the PCU can not work with it.
I introduced BER calculations in osmo-bts-trx some time ago for DATA, so the data is there - see gsm0503_coding.c, *_decode() functions. I also updated the code to pass this information to upper layers - see rx_tchf_fn(), rx_tchh_fn(), rx_pdtch_fn() in scheduler_trx.c. I tested that the data actually gets to measurement reports for TCH and SDDCH, but I don't remember if we tested this for GPRS. Are you sure it doesn't work with the current master? If so, it probably got broken during the rebase or after that.
I didn't do that for RACH, because currently RACH gating is performed in osmo-trx and works pretty well as far as I can tell, so osmo-bts-trx gets RACH's which are valid with high probability.
We can introduce an option to turn osmo-trx built-in RACH gating and rely on osmo-bts instead and then compare which one works better. That should be a minor change - I'm happy to implement this a bit later.