1. 1 1588v2 modules of time synchronization with frequency layer support draft-su-tictoc-1588v2-time-sync-modules-00 IETF 75 th, Stockholm TICTOC WG su.fei@zte.com.cn

2. 2 Motivation 1588v2 has being deployed in TD-SCDMA backhaul network for decreasing the use of GPS Profiles of 1588v2 system in this application should be outlined in appropriate document ITU-T Q13/15 also has intension to specify the 1588v2 telecom profiles for time/phase sync with frequency sync support (architecture preliminarily )

3. 3 Structure of document Introduction Scenario of 1588v2 time/phase sync for TD-SCDMA backhaul Time/phase server PTP client Timestamping process

4. 4 Introduction Time/phase requirement of TD-SCDMA has been recognized both in IETF TICTOC (draft-ietf-tictoc-requirements-00.txt) and ITU-T Q13/15 (G.8266) To endure stringent time/phase alignment between NodeB and RNC (+/-1.5 us) over a long span metro network (e.g. 30+ nodes maximum between some NodeBs and RNC), the time/phase sync is primarily considered to be coupled with frequency sync by operators

5. 5 Scenario of 1588v2 time/phase sync for TD- SCDMA backhaul The time/phase server synchronized by GPS and/or Compass is placed near RNC PTP client is implemented in NodeB or NEs connected to NodeB PTP client and all NEs on the time/phase distribution path has the same frequency traceability to PTP server or higher frequency reference through SyncE links

6. 6 Time/phase server Synchronized by other external time/phase source using varied time/phase interface (e.g. 1PPS+ToD, PTP, DCLS, IRIG). Support input antenna/cable delay compensation Provide multiple time/phase output interfaces (inter/intra office) and capacity of dealing with certain amount of PTP clients Frequency input for time/phase holdover and frequency output interfaces (e.g. 2Mbits and/or SyncE) Sync performance monitoring and management

7. 7 PTP Client Frequency reference selection and locking for measurement of local time/phase Time/phase calibration based on offset calculation carried out by PTP protocol

8. 8 Timestamping process Distributed timestamping scheme can be used to minimize the system delay of PTP event messages PTP event message is timestamped by edge timestamping unit close to physical interface The transient delay of PTP message directly forwarded (without being processed by PTP protocol unit) can be accurately measured and compensated

9. 9 Timestamping process Example of timestamping operations using delay request-response mode Ingress PHY interface

10. 10 Timestamping process Egress PHY interface

11. 11 Whats next Improve contents of the document based on discussions or comments from those who have interests Consider other aspects of the application e.g. sync protection, management, security etc. Merged with existing I-D draft-su-tictoc-time-sync-mode-01 which has the consistency with this one