No Handover from old 4G sites to new 4G sites

Hi All.

We have implemented new 4G sites, and old 4G sites do not process HO to new sites.

They measure A3 event, but no HO is triggered.

Huawei 4G

Adjacent is created.
Checked TAC and PCI is correct
Frequency also.

But have a lot drops for HO.

Does anybody have an idea about this issue?

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Is X2 setup and OK between those 2 sites?

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Yes, and the problem happens with many sites.

I see in your Actix picture lot of RACH attempts fail.
Did you get the RRC reconfig with mobility control info to HO to a new PCI?

No.

Only have measured for A3 event no more.

So you see event A3 reported?

Then if A3 reported and no RRC reconfig with mobility control info is a neighboring problem between those 2 enodeB.

Have some eNodeB traces between Source and Target mainly X2?

Here is an excellent description of all handover steps. Try to see where are you failing in your case: https://www.3glteinfo.com/wp-content/uploads/2013/12/NMC.LTE-X2-Handover.v1.0.pdf

I don’t have traces.

You need network traces, cannot troubleshoot without it.

Next step would be Handover request between source and target eNodeB.

I work with Nokia and Ericsson, this is my first time in Huawei and never have this issue with others vendors.

First check if ANR is ON on all sites.

No, only in NEW sites, OLD sites don’t have ANR, for this reason the adjacent need created manual.

Yes, I see a lot of RACH Fail.

Check the dedicated preamble for Non contention based.

Check RACH configuration parameters.

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Thanks a lot to help!

The problem with my issue was solved: OLD sites didn’t have X2 created with NEW sites, beacuse IP address was wrong.

It’s foremost audit to check when we have zero X2 attempts.

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