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Bug #2014

LC15: BTS does not properly handle BS-AG-BLKS-RES

Added by mqng2 12 days ago. Updated 12 days ago.

Status:
New
Priority:
Normal
Assignee:
-
Category:
osmo-bts-litecell15
Target version:
-
Start date:
04/18/2017
Due date:
% Done:

0%

Spec Reference:

Description

I have noticed that after changing BS-AG-BLKS-RES configuration from 1 to 2 or 3 from Osmo-NITB. The DSP starts to complain about unexpected burst as shown below.

[ERROR] : GsmL1_PhDataReq() : Unexpected burst (Invalid sapi) [Sapi = 6, Expected = 7]
[ERROR] : GsmL1_PhDataReq() : Unexpected burst (Invalid sapi) [Sapi = 6, Expected = 7]
[ERROR] : GsmL1_PhDataReq() : Unexpected burst (Invalid sapi) [Sapi = 6, Expected = 7]
[ERROR] : GsmL1_PhDataReq() : Unexpected burst (Invalid sapi) [Sapi = 6, Expected = 7]
[ERROR] : GsmL1_PhDataReq() : Unexpected burst (Invalid sapi) [Sapi = 6, Expected = 7]

Looking at ph_date_req function in src/osmo-bts-litecell15/l1_if.c, one can clearly see that the BTS always uses B0 for AGCH SAPI (line 392) leading to the DSP complaints about wrong SAPI for AGCH.

According to GSM 05.02, Section 7 Table 5 of 5, the number of blocks used AGCH must change according to BS-AG-BLKS-RES requested from BSC.

History

#1 Updated by mqng2 12 days ago

This issue has been fixed for LC15 BTS in the following commits

https://gitlab.com/nrw_noa/osmo-bts/commit/bcb0c02709b75645c2d10adffe9e0aabfbd516a3

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