Queries regarding L1 interface to osmo-bts for 11 bit RACH

Harald Welte laforge at gnumonks.org
Tue Mar 22 21:20:07 UTC 2016

Hi Bhargava,

On Tue, Mar 22, 2016 at 02:53:19PM +0000, Bhargava Abhyankar wrote:
> We have planned to support 11 bit RACH in osmo-pcu and osmo-bts. In
> this regard, we have  a query related to layer 1 to osmo-bts
> interface, as described below.

given that the current format relates to the history of the omso-bts
project and the first PHY that we interfaced it with, I think if we make
some changes now to the L1 interface (including L1SAP), we could
actually clean things up.

To do so, I would suggest to

a) on L1SAP, extend ph_rach_ind_param with

* a uint16_t for 'ra'
* add a member 'is_11bit' to indicate 8/11 bit
* an enum to indicate the different burst types

(and change the osmo-bts-* implementations as well as common code to use
 that updated definition)

b) on the PCU socket, perform similar changes to gsm_pcu_if_rach_ind

After performing above-mentioned changes, the formatting of the data
should be self-explanatory.

- Harald Welte <laforge at gnumonks.org>           http://laforge.gnumonks.org/
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