LTE Performance Case Studies Related to VoLT.pptx

LTE Performance Case Studies Related to VoLTE and feature parameter description

1. Section 10 LTE Performance Case Studies Related to VoLTE MAY CONTAIN U.S. AND INTERNATIONAL EXPORT CONTROLLED INFORMATION

2. 10. LTE Performance Case Studies Related to VoLTE 5. VoLTE RAN Features 6. VoLTE Call Termination 2. Initial Attach and Default Bearer Establishment 7. Intra-LTE Handover during VoLTE Call 9. VoLTE Emergency Calls 1. VoLTE Background 4. VoLTE Call Setup 3. IMS Registration & Deregistration 8. Inter-RAT Handover : Single Radio Voice Call Continuity ( SRVCC) 11. VoLTE Key Performance Indicators (KPIs) 12. VoLTE Performance Considerations

3. Topics Call Setup Failure ( MT Page Failure ) RLF and Recovery Delayed HO Resulting in RTP Packet Loss

4. Call Setup Failure (MT Page Failure) Both UEs have successfully completed IMS registration MO UE initiates a call and sends SIP INVITE Message to IMS core P-CSCF sends 100 TRYING, indicating the INVITE has been received, and 180 RINGING to MO UE Page is sent to MT UE, but ends up in a failure. Multiple pages could be sent, depending on the network’s paging scheme. IMS core eventually declares the MT UE temporarily unavailable and send SIP: 480 message to MT UE

5. Call Setup Failure – MO UE Log

6. Call Setup Failure – MT UE Log Pages (other UEs) Idle Reselection No Page was received at MT UE

7. Log Analysis Procedure: Call Setup Failure – MT Page Failure Open Files: MT_PageFailure_MT_UE.html MT_PageFailure_MO_UE.html Analysis Example – Call Setup Failure – MT Page Failure

8. Call Setup Failure – MO and MT UE Logs Step Look for Log Packet Time Stamp Verify MO UE 1 IMS SIP Message 0x156E 16:13:24.906 SIP INVITE UE initiates SIP INVITE 2 RACH procedure 0xB061 0xB167 0xB168 0xB169 0xB16A 0xB062 16:13:24.908 16:13:24.986 RACH cause: Connection Request RACH result: Success 3 IMS SIP Message 0x156E 16:13:25.267 SIP 100 TRYING from Network 4 IMS SIP Message 0x156E 16:13:29.556 180 RINGING (generated by network) 5 IMS SIP Message 0x156E 16:13:38.932 SIP 480 480 Temporarily Unavailable. Called party currently unavailable MT UE 1 EVENT_LTE_RRC_NEW_CELL_IND 0x1FFB 16:13:31.553 Cell reselection to PCI 221 2 EVENT_LTE_RRC_NEW_CELL_IND 0x1FFB 16:13:39.073 Cell reselection to PCI 439

9. Topics Call Setup Failure ( MT Page failure) RLF and Recovery Delayed HO Resulting in RTP Packet Loss

10. RLF and Recovery during VoLTE Call UE in an active VoLTE call declares RLF Cell acquisition initially fails and UE scans multiple frequencies Acquisition eventually passes and UE performs successful RACH procedure RTP traffic resumes RTP packet loss is observed

11. Log Analysis: RLF and Recovery during VoLTE Call . . . . . 4.4s Failed acquisitions Successful acquisition & RACH RTP packets 1500 – 1544 are lost

12. Log Analysis Procedure: RLF and recovery During VoLTE Call Open File: RLF_packet_loss.html Analysis Example – RLF and Recovery During VoLTE Call

13. RLF and Recovery During VoLTE Call: Log Walk-Through Step Look for Log Packet Time Stamp Verify 1 IMS RTP SN and Payload 0x1568 03:31:09.328 Through 03:31:09.765 RTP stream from network to UE with occasional dropped packets (like 03:31:09.514) 2 IMS RTP SN and Payload 0x1568 03:31:09.765 Last DL RTP packet before declaring RLF . Sequence = 1499 3 EVENT_LTE_RRC_RADIO_LINK_FAILURE 0x1FFB 03:31:09.774 UE declares Radio Link Failure 4 LTE Initial Acquisition Results 0xB176 03:31:09.843 through 03:31:13.885 Multiple acquisition failures over different bands for 4.4sec 5 LTE Initial Acquisition Results 0xB176 03:31:13.960 Successful acquisition 6 RACH Procedure 0xB062 03:31:14.181 Rach result = Success 7 LTE RRC OTA Packet 0xB0C0 03:31:14.140 03:31:14.305 RRC connection established 8 IMS RTP SN and Payload 0x1568 03:31:14.429 First DL RTP packet following RLF and acquisition. Sequence = 1545 9 IMS RTP Packet Loss 0x1569 03:31:14.429 Number Lost = 45 (packets 1500 through 1544)

14. Topics Call Setup Failure ( MT Page failure) RLF and Recovery Delayed HO Resulting in RTP Packet Loss

15. Analysis Example – Delayed HO Resulting in RTP Packet Loss First RTP packet after HO Last RTP packet before HO 113ms

16. Log Analysis Procedure: Delayed HO Resulting in RTP Packet Loss Open File: Delayed_HO Analysis Example – Delayed HO Resulting in RTP Packet Loss

17. Delayed HO Resulting in RTP Packet Loss: Log Walk-Through Step Look for Log Packet Time Stamp Verify 1 LTE RRC OTA Packet 0xB0C0 20:42:01.543 Measurement report 2 IMS RTP SN and Payload 0x1568 20:42:01.569 Last RTP Network-to-UE packet before HO. Sequence number = 3134 3 RRC Connection Reconfiguration 0xB0C0 20:42:01.628 mobilityControlInfo . Handover command to PCI 321 4 RACH Trigger 0xB061 20:42:01.650 RACH Reason = HO 5 RACH Procedure 0xB167 0xB168 0xB169 0xB16A 20:42:01.658 20:42:01.678 MSG1 through MSG4 6 RACH Attempt 0xB062 20:42:01.678 Rach result = Success 7 IMS RTP SN and Payload 0x1568 20:42:01.681 First RTP Network-to-UE packet before HO. Sequence number = 3136 8 IMS RTP Packet Loss 0x1569 20:42:01.681 Number Lost = 1