LTE UL sync failures increased after RAN upgrade

4G LTE
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1

Hello Experts,
On LTE UL sync failures increased after RAN upgrade from R12 to R15.
All parameters checked and no issue found in pre post parameters dump audit.
Vendor is Huawei.
Any suggestion?

2

Check also power in uplink counters, do you see any modification?
Pre post?

3

All parameters checked - no modification.

4

I mean counters not parameters.
SINR and power for PUSCH and PUCCH.
Lots of counters to compare what exactly was changed pre post.
Spend some time to study them and then you will see what is going on.
Huawei has now up to rel 16.1.
Is it TDD or FDD your network?

5

Network is FDD.

6

Between releases vendors sometime fix counters (change algorithm etc) and KPIs, check if that is the case.
You can find tht from release notes of RAN impact report.

If traffic pattern hasn’t changed (which is likely) and only SW was upgraded then issue is in counters or parameters.
Although your parameters values havent changed, parameters (and underline algorithm) might be changed, which again you can check from release notes.

7

Check sinr, rssi, interference and rsrp for pucch and pusch, and try to see if there is any trend change pre post for pucch and pusch.

8

Please check tatimer value.

9

Have you also checked reserved hidden parameters?
At upgrade most of previous (old) release reserved parameters are transformed into real parameters of new release.

10

Have you check that there was no Other Activity performed at same time?
UL Sync failure you mean CDR & ERAB KPI impacted, right?

11

Yes.
CDR increased.

12

I just check Network Impact report of eRAN15.1 (not sure if that is same as R15).
There are numbers of features introduced which may impact service drop rate.
Kindly check that report and you may your find answer there.

13

Can you please explain what you mean by “real parameters”?
Do you mean “adjustable”?

14

I mean are not hidden anymore and can be adjusted.

15

Issue resolved. Issue observed due to CLK issue