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									         VoIP over 1xEV-DO


         CDG Technology Forum on VoIP
              November 5, 2004

Page 1
  Outline
  • VoIP over 1xEV-DO Performance
         – Capacity & Latency
  • System Considerations
         – QoS
         – CDMA2000 1X Compatibility
         – Header Compression
  • Summary




Page 2
  Voice over IP over 1xEV-DO


            RN   IP   RNC   PDSN



                                    Core      Soft
                                   Network   Switch


                                        MGW
            RN   IP   RNC   PDSN


                                         PSTN


Page 3
Voice Quality vs. Delay (ITU-T G.114)



                           1X M-to-M




                           < 280 ms




  • CDMA2000 1X mobile-to-mobile latency: ~ 280 ms

Page 4
         VoIP over 1xEV-DO
              Capacity




Page 5
  VoIP Assumptions

  • Variable-rate EVRC
         – 1/8th rate frames are blanked
  • 1 RTP/UDP/IP packet per voice frame (no bundling)
  • ROHC Header Compression
         – 2 byte overhead per VoIP packet




Page 6
  Mobile-to-Mobile Latency Breakdown

     Vocoder            DO Modem                        DO RAN + PDSN
                                        RL Delay
         35 ms                 5 ms      Jitter              20 ms
                 Handset
                                   120 ms +                            Engineered
                         FL Delay Jitter + RL Delay Jitter       15 ms IP Network
                                + De-jitter Delay


                   De-jitter     DO
     Vocoder        buffer
                                                        DO RAN + PDSN
                                Modem   FL Delay
         20 ms                   5 ms     Jitter             20 ms
                 Handset
 • Target End-to-End FER = 3% (RF packet errors + Packet drop in de-jitter buffer)


Page 7
  Mobile-to-Landline Latency Breakdown

    Vocoder       DO Modem                          DO RAN + PDSN
                                 RL Delay
                                  Jitter                20 ms
     35 ms          5 ms
              Handset
                                    110 ms +
                                  RL Delay Jitter           15 ms Engineered
                                                                    IP Network
                                 + De-jitter Delay


                                            PSTN           MGW

                                            20 ms          15 ms

  • Target End-to-End FER = 2%

Page 8
  Landline-to-Mobile Latency Breakdown

               De-jitter    DO
   Vocoder      buffer     Modem                       DO RAN + PDSN
                                    FL Delay
                                      Jitter               20 ms
    20 ms                  5 ms
             Handset
                                      115 ms +
                                    FL Delay Jitter            15 ms Engineered
                                                                       IP Network
                                   + De-jitter Delay


                                               PSTN           MGW

                                               20 ms          35 ms

  • Target End-to-End FER = 2%


Page 9
  Airlink Simulation Assumptions
  • 19 3-sector cells
  • 3GPP2 channel model and evaluation methodology
  • Users randomly distributed in the coverage area
          – 3GPP2 mixed speed distribution
  • 2 km cell-to-cell distance with 138 dB max path loss
  • All neighbor sectors generate forward link
    interference 100% of the time (conservative)
  • All key Rev A features simulated
          – Multi-user packets, QoS scheduler, H-ARQ, D-ARQ, etc.



Page 10
Mobile-to-Mobile Call Latency (1 AT Ant)
                                                 100%


                                                 90%


                                                 80%
          Percentage of Users with Latency < X




                                                 70%


                                                 60%
                                                                                                                        20 Erlangs
                                                 50%                                                                    30 Erlangs
                                                                                                                        40 Erlangs
                                                 40%

                                                 30%

                                                 20%


                                                 10%


                                                  0%
                                                        180   200   220       240          260        280   300   320
                                                                          End-to-end latency [msec]




  • Target FER = 3%
Page 11
Mobile-to-Mobile Call Latency (2 AT Ant)
                                                 100%


                                                 90%


                                                 80%
          Percentage of Users with Latency < X




                                                 70%


                                                 60%
                                                                                                                        20 Erlangs
                                                 50%                                                                    30 Erlangs
                                                                                                                        40 Erlangs
                                                 40%

                                                 30%

                                                 20%


                                                 10%


                                                  0%
                                                        180   190   200              210              220   230   240
                                                                          End-to-end latency [msec]




  • Target FER = 3%
Page 12
  Landline Call Latency (1 AT Antenna)
                                                 100%


                                                 90%


                                                 80%
          Percentage of Users with Latency < X




                                                 70%


                                                 60%
                                                                                                                        20 Erlangs
                                                 50%                                                                    30 Erlangs
                                                                                                                        40 Erlangs
                                                 40%

                                                 30%

                                                 20%


                                                 10%


                                                  0%
                                                        140   160   180       200          220        240   260   280
                                                                          End-to-end latency [msec]




  • Target FER = 2%
Page 13
  RL Rise-over-Thermal (ROT) Histogram
                100%


                90%


                80%


                70%


                60%
                                                                           20 Erlangs
                                                                           30 Erlangs
          CDF




                50%
                                                                           40 Erlangs
                                                                           45 Erlangs
                40%


                30%


                20%


                10%


                 0%
                       0   1   2   3   4      5       6   7   8   9   10
                                           ROT [dB]




  • Less than 1% outage at 7 dB at 40 Erlangs
Page 14
  Capacity and Latency Summary

  • Latency at 40 Erlangs Load
            Coverage        98%      95%      90%

          M-to-M 1 ant     300 ms   280 ms   270 ms

          M-to-M 2 ant     230 ms   225 ms   220 ms

          Landline 1 ant   235 ms   220 ms   210 ms

          Landline 2 ant   185 ms   180 ms   180 ms




Page 15
  Other System Considerations

  • Quality of Service
  • CDMA2000 1X Compatibility
  • Header Compression




Page 16
  Multi-Flow RLP for QoS
                                 Best Effort Flow
                  RLP NAK: Enable, DARQ: Disable, Scheduler: BE
     1xEV-DO
       RAN        RLP NAK: Disable, DARQ: Enable, Scheduler: EF
                                   VoIP Flow

  • Allows 1xEV-DO RAN to apply different treatment to
    VoIP flows
          – Disables RLP NAK’s and enables D-ARQ
          – Applies priority scheduling
  • Allows subscribers to use other applications while
    on a VoIP call

Page 17
  QoS Interfaces


                   IS-835-D: QoS Signaling



                              RN    IP     RNC     PDSN

      Handset

                IS-856-A: Multi-flow RLP     IS 878-A:
                                              A10/A11




Page 18
  Key Performance Algorithms
          VoIP   BE   VoIP   BE    VoIP   BE   VoIP   BE   VoIP   BE   VoIP   BE


 User
Queues
          User # 1    User # 2     User # 3    User # 4    User # 5    User # 6


                                  Scheduler




  • Airlink scheduling
  • Admission & overload control
  • Fast sector switching

Page 19
  Compatibility with CDMA2000 1X
          CDMA2000 1X Region        CDMA2000 1X & 1xEV-DO Region


              CDMA2000 1X                CDMA2000 1X    1xEV-DO
                Network           ←        Network       Network
                                Active
                               Handoff
                                                Interoperable




     CDMA2000 1X       1xEV-DO           CDMA2000 1X      1xEV-DO
       Phone           VoIP Phone          Phone          VoIP Phone




Page 20
  Header Compression

  • RTP/UDP/IP header overhead is significant
          – 40 bytes
          – Voice payload at 8 kbps is only 20 bytes (20 ms frame)
  • Candidate compression algorithms
          – ROHC: reduces header to 1-2 bytes
          – eCRTP: reduces header to 4 bytes
  • Can be implemented in the PDSN or RNC
          – With segment-based framing in Enhanced Multi-Flow
            Packet Application



Page 21
  Summary
 • Evolution to VoIP is the next major transition in
   wireless networks
 • 1xEV-DO Rev A is designed to carry data/voice traffic
   in all-IP format
 • With a well-engineered IP core network, commercial-
   grade VoIP over 1xEV-DO Rev A is promising
      – Call capacity greater than that of CDMA2000 1X is possible
      – 2 antenna handsets may be required to maintain acceptable
        latency near cell edge at 40 Erlangs




Page 22
          Thank You




Page 23

								
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