Possible reasons for 100% Inter HO Prep Fail?

Mobility
1

Hello Experts.

What can be possible reasons for 100% Inter HO Prep Fail?
Distance of NBR site is 1.5 Miles.
E// system

2

May be MME configuration issue.
Is it MME border site?

3

No border site.
MME pool are same on source & target node.

4

So is it S1 handover or X2 prep failures?

5

X2 prep failures.

6

May be your X2 link fault.
Or X2 disable case.

7

Termpoints are UP.
Anything to check?

8

Link faulty.
Wrong X2 IP, check with neighbor site.
Is incoming proper HO?

9

Failing with all target sites or only 1 specific site?

10

Source site has relations with 2 NBR sites only and all are failing 100%.
Source is DAS.
Target 2 are macro

11

Any PCI conflict?

12

HO Parameters & features defined as per operator Gold standard sheet.
MME pool are same on source & target node.
Distance of NBR site is 1.5 Miles.
No PCI Conflict observed.
EutranfreqcellRelation Deleted & ANR added.
Adjusted Delay in CIO but no major impact observed.
No Utilization issue observed in target nodes.

13

Better to forbid that das to macro far away.

Why handover needed from that DAS to macro?

14

Are those 2 target macros taking incoming HO from other sites?
Just checking issue in target or DAS to macro pair.

15

Yes, macro to other nodes are good.

16

You can forbid that NBRr if attempts are very very low and not required.
From DAS to macro.

17

Not macro to other nodes.
Other nodes to macro, is HO happening?

18

Yes other node to macro is working.

19

Is there any eNodeB ID changed on NBR node or else same eNodeB ID?

20

Ok. Means issue is in that DAS Or das to 2 eNB pairs.
I don’t know Ericsson parameters but check ishoallowed Or check those 2 eNBs are not in x2 blacklist in DAS.