How and in what conditions Handover failure occurs and How to save or avoid such failures in LTE?

Question

In our market we are getting S1 HO failures to great extent but could not get the root cause if its eNB side or MME side.

How can we improve this S1 HO failures rate and if there is any feature that can be implemented to reduce the failures then please let us know.

Answer 1

Few scenarios what I know in the context of handover failure.
1 . Handover Preparation gets failed at target eNodeB, in that case target eNodeB sends "Handover Preparation Failure" to source eNodeB.
2. Handover Command (RRC Connection Reconfiguration) is received by UE when it could not latch on target eNodeB. This probably happens due to bad radio conditions.

In case of point 1, need to check the failure "cause" value and take the corrective action.
In case of point 2, need to adjust measurement config and reporting related parameters.