VoLTE drop due to handover prepation failed

Hey Experts.

Have some one faced VoLTE drop due to handover prepation failed?

Is it really abnormal?

Might be execution fail.

  1. Check TAU of source and target eNB
  2. If its happining in busy hours, check target cells resources or utilization
  3. Target eNB in outage or any operational issues
  4. Same site or target having S1 Ap or other txm alarms or Links to MME
  5. See handover parameters are ok or not… and target cells parameters are as per gpl or not
  6. Handover is allowed to target cell or not… some times we barree it…
  7. Volte enabaled or not on target cells
  8. checkif complete cluster is impacted or not
  9. check mme of both source and target enb… if diff than mme pooling has to enabled
  10. Number of VoLTE users per cells

Lastly take relational report to see actuall cause.

Some of the actions are applicable for both data and voice.

Prepration will come in picture before handover but final handover by execution.

Yes, correct.

It is failed in preparation.

We can see failure in both two phases but with different reasons.

You should check X2 or S1 failure reason.