This article is about Measurements Related to E-RAB (LTE), E-RAB Setup Drop Measurement and we collected list of counters which shows eRAB drops. After, we discussed one by one RF optimization solutions and actions can be taken by RF 4G optimization engineer.
What are eRAB Drop Counters and its Optimization Solutions?
| Counter Name | Failure Cause | Solution |
| L.E-RAB.AbnormRel.MMETot.VoIP | MME-triggered abnormal releases of E-RABs for voice services | Check Alarm / Raise with core team. |
| L.E-RAB.AbnormRel.Radio.SRBReset.VoIP | The RLC PDU for an SRB has been retransmitted for the maximum number of times. | SrbRlcPdcpCfg.VolteEnodebMaxRetxThld :- Improving the anti interference capability and decreasing voice service drop. Â Increase UePollRetransmitTimer & ENodeBPollRetransmitTimer / Increase VolteEnodebMaxRetxThld |
| L.E-RAB.AbnormRel.Radio.NoReply.VoIP | No responses from the UE. | Poor Coverage and High UL RSSI. If poor coverage issue:- Improve coverage by tilt and power and Feature TTI Bundling. If UL RSSI:- Tune P0NominalPUCCH / P0NominalPUSCH. |
| L.E-RAB.AbnormRel.Radio.ULSyncFail.VoIP | Uplink resynchronization failures. | Tune RlfTimerConstGroup.N310/N311/T310/T311 |
| L.E-RAB.AbnormRel.MME.EUtranGen.VoIP | The MME with the release cause of Release due to E-UTRAN Generated Reason. | |
| L.E-RAB.AbnormRel.Radio.VoIP | Faults at the radio network layer. | Check Cell Downtime /Fluctuation. |
| L.E-RAB.AbnormRel.HOFailure.VoIP | Handover failures. | Check worst relation – PCI clash, Confusion, RSI Clash, extended cell range. Check A3 Parameters – Disabled or enabled , Tune A2 Threshold / A5 hystersis, Offset / CIO. Tune GlobalProcSwitch.HoErabConflProcessingStrat and check ERAB SR should not be degraded. |
| L.E-RAB.AbnormRel.Cong.VoIP | Radio network congestion | Check congestion threshold (PRB), Offload traffic by Load balancing /Quick handoff triggering due to rf condition. |
| L.E-RAB.AbnormRel.MME.VoIP | MME-triggered abnormal releases of activated E-RABs for voice services | |
| L.E-RAB.AbnormRel.TNL.VoIP | Faults at the transport network layer. | Raise to Tx Team. |
| L.E-RAB.AbnormRel.Cong.PreEmp.VoIP | Radio resource preemption. | Check Preemption configuration. |
| L.E-RAB.AbnormRel.Cong.Load.VoIP | Radio resource overload. | Offload traffic by Load balancing / Quick handoff triggering due to rf condition. |
| L.E-RAB.AbnormRel.TNL.PreEmp.VoIP | Transport resource preemption. | Check Alarm / Raise with Tx team. |
| L.E-RAB.AbnormRel.TNL.Load.VoIP | Transport resource overload. | Check Alarm / Raise with Tx team. |
| L.E-RAB.AbnormRel.UlWeak.VoIP | Uplink weak coverage. | 1. Activation of TTI Bundling. 2. VolTE Comp if no resource crunch. 3. Tune power or tilt to make dominant server. |
| L.E-RAB.AbnormRel.Other.VoIP | Other reasons | Tune InitPdcchSymNum/QciPara.UeInactiveTimerPri/CellRacThd.VolteReservedNumber/CellDrxPara.VoltePlrThldForExitingDrx/CellDrxPara.SinrThldForVolteDrxCtrl |
| L.E-RAB.AbnormRel.Radio.Other.VoIP | Faults at the radio network layer. | Check Alarm / Handover Failure. |
| L.E-RAB.AbnormRel.TNL.Other.VoIP | Faults at the transport network layer. | Check Alarm / Raise with Tx team. |
| L.E-RAB.AbnormRel.Cong.Other.VoIP | Other radio resource congestion reasons. | Check congestion threshold. |
| L.E-RAB.AbnormRel.MMETot.EUtranGen.VoIP | The core network with the release cause “Release due to E-UTRAN Generated Reason”. | Check Alarm / Raise with core team. |
| L.HHO.S1.IntraFreq.MMEAbnormRsp.VoIP | Abnormal causes received by the eNodeB from the MME during S1-based outgoing intra-frequency handover executions for voice services in a cell. | Tune S1MessageWaitingTimer/X2MessageWaitingTimer/UuMessageWaitingTimer. |
| L.HHO.S1.InterFreq.MMEAbnormRsp.VoIP | Abnormal causes received by the eNodeB from the MME during S1-based outgoing inter-frequency handover executions for voice services in a cell | Tune S1MessageWaitingTimer/X2MessageWaitingTimer/UuMessageWaitingTimer. |
| L.HHO.S1.InterFddTdd.MMEAbnormRsp.VoIP | Abnormal causes received by the eNodeB from the MME during S1-based outgoing inter-duplex-mode handover executions for voice services in a cell. | Tune S1MessageWaitingTimer/X2MessageWaitingTimer/UuMessageWaitingTimer. |
| L.E-RAB.AbnormRel.MMETot.QCI5 | Abnormal E-RAB releases for QCI-5 services because of faults on the core network side. | Check Alarm / Raise with core team. |
| L.E-RAB.AbnormRel.Radio.QCI5 | Abnormal releases of activated QCI-5 E-RABs due to faults at the radio network layer. | Check Alarm. |
| L.E-RAB.AbnormRel.MMETot.VoIP.PLMN | MME-triggered abnormal releases of E-RABs for voice services for a specific operator. | |
| L.E-RAB.AbnormRel.Radio.SRBReset.VoIP.PLMN | The RLC PDU for an SRB has been retransmitted for the maximum number of times for a specific operator. | |
| L.E-RAB.AbnormRel.Radio.NoReply.VoIP.PLMN | No responses from the UE for a specific operator. | |
| L.E-RAB.AbnormRel.Radio.ULSyncFail.VoIP.PLMN | Uplink resynchronization failures for a specific operator. | |
| L.E-RAB.AbnormRel.MME.EUtranGen.VoIP.PLMN | The MME with the release cause of Release due to E-UTRAN Generated Reason for a specific operator. | |
| L.E-RAB.AbnormRel.Radio.VoIP.PLMN | Faults at the radio network layer for a specific operator. | |
| L.E-RAB.AbnormRel.HOFailure.VoIP.PLMN | Handover failures for a specific operator. | |
| L.E-RAB.AbnormRel.Cong.VoIP.PLMN | Radio network congestion for a specific operator. | |
| L.E-RAB.AbnormRel.MME.VoIP.PLMN | MME-triggered abnormal releases of activated E-RABs for voice services for a specific operator. | |
| L.E-RAB.AbnormRel.TNL.VoIP.PLMN | Faults at the transport network layer for a specific operator. | |
| L.E-RAB.AbnormRel.TNL.PreEmp.VoIP.PLMN | Transport resource preemption for a specific operator. | |
| L.E-RAB.AbnormRel.TNL.Load.VoIP.PLMN | Transport resource overload for a specific operator. | |
| L.E-RAB.AbnormRel.Cong.PreEmp.VoIP.PLMN | Radio resource preemption for a specific operator. | |
| L.E-RAB.AbnormRel.Cong.Load.VoIP.PLMN | Radio resource overload for a specific operator. | |
| L.E-RAB.AbnormRel.Other.VoIP.PLMN | Other reasons for a specific operator. | |
| L.E-RAB.AbnormRel.Radio.Other.VoIP.PLMN | Other faults at the radio network layer for a specific operator. | |
| L.E-RAB.AbnormRel.TNL.Other.VoIP.PLNM | Faults at the transport network layer for a specific operator. | |
| L.E-RAB.AbnormRel.Cong.Other.VoIP.PLMN | Other radio resource congestion reasons for a specific operator. | |
See Also: eRAB Failure Counters with RF Optimization Solutions.