Reasons for IHSR degraded

4G LTE
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1

Hi Experts,
IHSR is degraded due to incoming handover preparation failures because of load-based admission failure in a cell (Top N fail with facing NBRs), what could be the reason for this? (OEM is Huawei)

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X2 prep fail out also increased from same date:
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2

Lst cellmlbho, and check admit switch is off or on.

3

HoAdmitSwitch is ON on all layers.

4

Check if the source cell is potentially highly loaded.

5

Utilization is high but this was high before these failures as well.

6

@Umar_Mir, I am not aware of Huawei parameters, but you can check the below two methods.

  1. If it is multicarrier sites (like if you have two intra band frequency on the site then mfbi (multi frequency band indicator) should be enabled towards all the neighbouring relation).
  2. Check the UE measurement frequency is assigned to it correct DL frequency or not (sometime when u do frequency retuning this will miss).
7

Any change in MLB thresholds?

8

Are the accessibility KPIs ok?

9

Access KPIs are fine.

10

MLB thresholds are same as before.

11

No discrepancy of frequency in cell and EUTRAN external table.

12

Check:
ANR X2;
If path are created to the other side to ANR create the X2 relations;
IPPATH;
Look the neighbors that try to do the preparation.

13

Neighbors that try to do the preparation: its facing NBRs and both have increased failures as incoming from each other same date.
ANR X2 i will check and confirm.

14

Ho admit switch off can solve (I have faced this KPI issue).
X2 faulty and handover going through S1 but coverage KPI of HOSR also get degraded.

15

So this means X2 Interface Fault can cause this issue as one of thee two cells involved has this alarm too as Ho admit switch was ON before too?

16

Yes, fault X2 will cause issue.
If you barred that site and is first tier then too issue if other sites can handle handover can forbid.

17

Did you check layer3 message?
Serving enodeb Received “Handover request ack” message after “handover request” which sent by serving enodeb, please check this message.