LTE: What can be reason of handover preparation failure ?

Question

Newly integrated 3rd carrier is facing IRAT handover failure with reason "unknown-targetID" and "Failure In Target EPC/eNB Or Target System". Other carriers of same enodeB are doing successful handover with the same WCDMA cell. Sometimes for the affected cell, handover is successful.

Thanks in advance,
Bijit

Answer 1

HO procedure could be interrupted also by TAU in the Source eNB

Comments

how TAU interrupt the HO?

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Its a old thread, it may be better if you can ask a fresh query :) so that it reaches to more people.

Answer 2

It is a very generic query. I am assuming here your query is related to intra Lte handover. Handover preparation failure can be happened at any of the following nodes:
1. Source MME
2. Target MME
3.Target SGW.
4. Target eNodeB

There can be a number of failure reasons like target eNodeB doesn't have radio resource any more to server a cater one more UE. Please refer 3GPP 36.413 section 9.2.1.3, which has list of the possible causes

Comments

All what Vimal said is true.

Adding one thing from top of my head.. The HO procedure could be interrupted also by TAU in the Source eNB