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Smooth Evolution Path from Legacy to NGN Synchronization at ITSF 2014

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Dominik Schneuwly examines how to evolve from legacy to next-generation network synchronization

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Smooth Evolution Path from Legacy to NGN Synchronization at ITSF 2014

  1. 1. Smooth Evolution Path from Legacy to NGN Synchronization Dominik Schneuwly, ITSF 2014
  2. 2. © 2014 ADVA Optical Networking. All rights reserved.2 Outline • Drivers of the evolution • Dimensions of the evolution • Evolution starting points • Evolution phases and end points • Evolution path examples • Conclusions
  3. 3. © 2014 ADVA Optical Networking. All rights reserved.3 Driver of the evolution • Network technology evolution from TDM to packet-switched networks, and from fixed to fixed & mobile end sytems • Synchronization in the past: • Driver: TDM switching (telephony) and transmission (SDH) • Reasons: limit under- and overflowing of frame buffers, allow crossconnecting (SDH) • Requirements: frequency, accuracy 1·10-11 (relative freq. acc.) • Synchronization at present and in the future: • Driver: mobile base stations, e.g. 2G BTS, 3G Node B, 4G eNB • Reasons: successful call handover efficient use of sparse spectrum & channel capacity etc. • Requirements: frequency (1.6E-8) and phase (1.5 μs ⇾ hundreds ns)
  4. 4. © 2014 ADVA Optical Networking. All rights reserved.4 Dimensions of the evolution • Change in synchronization needs • Old: frequency for the entire network (1E-11) • New: frequency (1.6E-8) and phase (1.5 μs ⇾ hundreds ns) for the network edge • Change in network technology • Old: TDM networks (PDH, SDH) • New: packet-switched networks • Ethernet, Synchronous Ethernet (SyncE) • IP, IP/MPLS • Etc. • Change in synchronization technology • Old: SDH/SONET, E1/T1 over PDH • New: SyncE, PTP (IEEE 1588 v2) Synchronization technology Synchronization needs Network context
  5. 5. © 2014 ADVA Optical Networking. All rights reserved.5 Once more: frequency, phase and time-of-day t t Clock signal of system A Clock signal of system B ! !! t t Time signal of system A Time signal of system B 14/01/00 08:34:56 14/01/00 08:34:57 14/01/00 08:34:55 14/01/00 08:34:55 14/01/00 08:34:56 14/01/00 08:34:57 System A System B t t Clock signal of system A Clock signal of system B TA = 1 / fA TB = 1 / fB fA = fB• Frequency synchronization • Phase synchronization • Time-of-Day synchronization
  6. 6. © 2014 ADVA Optical Networking. All rights reserved.6 Application Radio Interface Backhaul Frequency Phase Frequency Phase CDMA 2000 ±50ppb ±3 to 10µs GPS GPS GSM ±50ppb n/a ±16ppb n/a WCDMA ±50ppb n/a ±16ppb n/a LTE (FDD) ±50ppb n/a ±16ppb n/a LTE (TDD) ±50ppb ±1.5µs ±16ppb ±1.1µs LTE-A MBMS ±50ppb ±1 to 5µs ±16ppb ±1µs (G.8271) LTE-A CoMP LTE-A CoMP JT ±50ppb ±1 to 5µs ± 0.5µs ±16ppb ±1.1µs < 0.5µs (?) LTE-A eICIC ±50ppb ±1 to 3µs ±16ppb ±1.1µs Frequency and phase synch. requirements MBMS: Multimedia Broadcast Multicast Services CoMP: Coordinated Multipoint eICIC: enhanced Inter-Cell Interference Coordination JT: Joint Transmission
  7. 7. © 2014 ADVA Optical Networking. All rights reserved.7 Starting point 1: central PRC PRC SDH SSU SSU SSU SSU SSU • Frequency synchronization with accuracy = 1E-11 • Generation: central PRC, typically atomic Cesium clock • Distribution: SDH, physical layer; sometimes E1/T1 in «last mile»
  8. 8. © 2014 ADVA Optical Networking. All rights reserved.8 Starting point 2: distributed PRCs SDH Subnetwork PRC SDH Subnetwork PRC SDH Subnetwork PRC • Frequency synchronization with accuracy = 1E-11 • Generation: distributed PRCs, typically GNSS receivers • Distribution: SDH, physical layer; sometimes E1/T1 in «last mile»
  9. 9. © 2014 ADVA Optical Networking. All rights reserved.9 Transition phases • Main transition phases: • A: Frequency over TDM network • SDH/SONET • B: Frequency over packet network • SyncE • PTP / No Timing Support (G.8265.1) • C: Phase over packet network • PTP / Full Timing Support (G.8275.1) with SyncE • PTP / Full Timing Support (G.8275.1) without SyncE (ITU-T: «ffs») • PTP / Assisted Partial Timing Support (G.8275.2) A B C (less common)
  10. 10. © 2014 ADVA Optical Networking. All rights reserved.10 Transition A → B B / A SDH & PDH SyncE X G.8265.1 X Transition B → C C / B SyncE G.8265.1 G.8275.1 X X G.8275.2 X X Many evolution scenarios Transitions A → B → C: SDH & PDH → SyncE → G.8275.1 SDH & PDH → SyncE → G.8275.2 SDH & PDH → G.8265.1 → G.8275.1 SDH & PDH → G.8265.1 → G.8275.2
  11. 11. © 2014 ADVA Optical Networking. All rights reserved.11 There are more evolution scenarios than that! • Already mentioned: Starting point (SDH & PDH) can be with centralized or with decentralized PRCs • There are multiple mobile systems (2G, 3G, 4G); evolution scenarios may be different for each of them • Multiple network ownerships (mobile operator, transport provider, etc.) • Networks with equiment from multiple vendors: different equipment roadmaps • Some operators use CES/PWE for their 2G BTS (PDH over packet network) • And we haven’t mentioned WDM systems in conjunction with phase synchronization … • Etc., etc.
  12. 12. © 2014 ADVA Optical Networking. All rights reserved.12 Evolution example 1a: SDH & PDH → SyncE → G.8275.1 Leverage existing PRC and SSUs SSU PRC SDH or SyncE SyncE SSU PRC SDH SDH & PDH Physicallayerbased Packetbased(PTP) Upgrade to SyncE
  13. 13. © 2014 ADVA Optical Networking. All rights reserved.13 Evolution example 1a: SDH & PDH → SyncE → G.8275.1 Leverage existing PRC and SSUs, just add cards to SSUs for phase SSU PRC SDH SyncE SSU PRC SDH SDH & PDH SSU SyncE GNSS card T-GM card GNSS Physicallayerbased Packetbased(PTP) G.8275.1 Deploy Boundary Clocks Add cards Upgrade to PTP Slave Upgrade to SyncE Core
  14. 14. © 2014 ADVA Optical Networking. All rights reserved.14 Evolution example 1b: keep PRC for phase holdover Leverage existing PRC and SSUs, just add cards to SSUs for phase SSU PRC SDH or SyncE SyncE SSU PRC SDH SDH & PDH SSU SyncE GNSS card T-GM card GNSS Physicallayerbased Packetbased(PTP) G.8275.1 Deploy Boundary Clocks Add cards Upgrade to PTP Slave Upgrade to SyncE PRC SDH or SyncE For Holdover: frequency holds phase & time
  15. 15. © 2014 ADVA Optical Networking. All rights reserved.15 Evolution example 1c: starting with decentralized PRCs Leverage existing GNSS/SSUs, just add T-GM card to SSUs for phase SyncESDH & PDH Physicallayerbased Packetbased(PTP) Upgrade to SyncE GNSS card GNSS SSU GNSS card GNSS SSU Local PRC Local PRC
  16. 16. © 2014 ADVA Optical Networking. All rights reserved.16 Evolution example 1c: starting with decentralized PRCs Leverage existing GNSS/SSUs, just add T-GM card to SSUs for phase SyncESDH & PDH SSU SyncE GNSS card T-GM card GNSS Physicallayerbased Packetbased(PTP) G.8275.1 Deploy Boundary Clocks Add card Upgrade to PTP Slave Upgrade to SyncE GNSS card GNSS SSU GNSS card GNSS SSU Local PRC Local PRC Local PRTC
  17. 17. © 2014 ADVA Optical Networking. All rights reserved.17 Evolution example 2a: SDH & PDH → SyncE → G.8275.2 Add cards to SSUs and add small APTS units for phase SSU PRC SDH or SyncE SyncE SSU PRC SDH SDH & PDH Physicallayerbased Packetbased(PTP) Upgrade to SyncE
  18. 18. © 2014 ADVA Optical Networking. All rights reserved.18 Evolution example 2a: SDH & PDH → SyncE → G.8275.2 Add cards to SSUs and add small APTS units for phase SSU PRC SDH or SyncE SyncE SSU PRC SDH SDH & PDH SSU SyncE GNSS card T-GM card GNSS Physicallayerbased Packetbased(PTP) G.8275.2 Add cards Upgrade to PTP Slave Upgrade to SyncE APTS GNSS G.8275.2 Add APTS unit First Aggregation node
  19. 19. © 2014 ADVA Optical Networking. All rights reserved.19 Evolution example 3a: SDH & PDH → G.8265.1 → G.8275.1 Leverage existing PRC and SSUs, just add cards to SSUs for phase PRC SDH or Synce Carrier Ethernet SSU PRC SDH SDH & PDH Physicallayerbased Packetbased(PTP) Upgrade to SyncE G.8265.1 T-GM card Add card SSU
  20. 20. © 2014 ADVA Optical Networking. All rights reserved.20 Evolution example 3a: SDH & PDH → G.8265.1 → G.8275.1 Leverage existing PRC and SSUs, just add cards to SSUs for phase PRC SDH or Synce Carrier Ethernet SSU PRC SDH SDH & PDH SSU Carrier Ethernet GNSS card T-GM card GNSS Physicallayerbased Packetbased(PTP) Deploy Boundary Clocks Add card Upgrade to PTP Slave Upgrade to SyncE Core G.8265.1 T-GM card Add card SSU G.8275.1
  21. 21. © 2014 ADVA Optical Networking. All rights reserved.21 Evolution example 4a: SDH & PDH → G.8265.1 → G.8275.2 Add cards to SSUs and add small APTS units for phase PRC SDH or SyncE Carrier Ethernet SSU PRC SDH SDH & PDH Physicallayerbased Packetbased(PTP) Upgrade to SyncE T-GM card SSU Add card G.8265.1
  22. 22. © 2014 ADVA Optical Networking. All rights reserved.22 Evolution example 4a: SDH & PDH → G.8265.1 → G.8275.2 Add cards to SSUs and add small APTS units for phase PRC SDH or SyncE Carrier Ethernet SSU PRC SDH SDH & PDH Physicallayerbased Packetbased(PTP) Upgrade to SyncE T-GM card SSU SSU Carrier Ethernet GNSS card T-GM card GNSS G.8275.2 Add card Upgrade to PTP Slave APTS GNSS G.8275.2 Add APTS unit First Aggregation node Add card G.8265.1
  23. 23. © 2014 ADVA Optical Networking. All rights reserved.23 Conclusions • Evolution is driven by changes in synchronization needs, network context and synchronization technologies • There are many possible evolution scenarios • Leveraging existing SSUs and PRCs is possible with many evolution scenarios • Within these scenarios, evolution requires addition on T-GM cards in SSUS, and possibly addition of small APTS units • Chosen evolution path has important impact on CAPEX • Optimal planning of the evolution path is a must
  24. 24. IMPORTANT NOTICE ADVA Optical Networking is the exclusive owner or licensee of the content, material, and information in this presentation. Any reproduction, publication or reprint, in whole or in part, is strictly prohibited. The information in this presentation may not be accurate, complete or up to date, and is provided without warranties or representations of any kind, either express or implied. ADVA Optical Networking shall not be responsible for and disclaims any liability for any loss or damages, including without limitation, direct, indirect, incidental, consequential and special damages, alleged to have been caused by or in connection with using and/or relying on the information contained in this presentation. Copyright © for the entire content of this presentation: ADVA Optical Networking. Thank you schneuwly@oscilloquartz.com

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