Bhargava,

This answer only applies to platforms that use the NuRAN PHY (SuperFemto, LiteCell 1.x, ...).

1. For 11 bit RACH, in PH-RA-IND sent from layer 1.

· Whether 'u8Size' will be 2 in case of 11 bit RACH ?

[YGOD] Yes it will.

· What is the alignment of 11 bits inside 'u8Buffer ?

[YGOD] Data is packed LSB first

2. How osmo-bts can distinguish between types of 11 bit RACH based on received layer 1 message ? (spec 44.060 section 11.2.5a)

· is burst type GsmL1_BurstType_Access_0 equivalent to GPRS_8_BIT_RACH/ GPRS_11_BIT_RACH

· is burst type GsmL1_BurstType_Access_1 equivalent to EGPRS_8_PSK_11_BIT_RACH

· is burst type GsmL1_BurstType_Access_2 equivalent to EGPRS_NO_8_PSK_11_BIT_RACH

[YGOD] Yes, you are correct. GsmL1_BurstType_Access_0 is for the "normal" access bursts, GsmL1_BurstType_Access_1 is for TS1 and GsmL1_BurstType_Access_2 is for TS2.

Best Regards,

Yves

De : osmocom-net-gprs [mailto:osmocom-net-gprs-bounces@lists.osmocom.org] De la part de Bhargava Abhyankar Envoyé : March-22-16 10:53 AM À : osmocom-net-gprs@lists.osmocom.org Objet : Queries regarding L1 interface to osmo-bts for 11 bit RACH

Hello,

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.

1. For 11 bit RACH, in PH-RA-IND sent from layer 1.

· Whether 'u8Size' will be 2 in case of 11 bit RACH ?

· What is the alignment of 11 bits inside 'u8Buffer ?

2. How osmo-bts can distinguish between types of 11 bit RACH based on received layer 1 message ? (spec 44.060 section 11.2.5a)

· is burst type GsmL1_BurstType_Access_0 equivalent to GPRS_8_BIT_RACH/ GPRS_11_BIT_RACH

· is burst type GsmL1_BurstType_Access_1 equivalent to EGPRS_8_PSK_11_BIT_RACH

· is burst type GsmL1_BurstType_Access_2 equivalent to EGPRS_NO_8_PSK_11_BIT_RACH

Regards

Bhargava Abhyankar

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.

Regards, Harald