Recommendation ITU-T G.8271/Y.1366 (03/2020) Time and phase synchronization aspects of telecommunication networks
Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
4 Abbreviations and acronyms
5 Conventions
6 The need for time and phase synchronization
7 Time and phase synchronization methods
     7.1 Distributed PRTC
          7.1.1 Main characteristics
     7.2 Packet based methods with timing support of intermediate nodes
          7.2.1 Main characteristics
8 Network reference model
     8.1 Access section of HRM with PTP/native access IWF
9 Time and phase synchronization interfaces
Annex A  One pulse-per-second (1PPS) time and phase synchronization interface specification
     A.1 1PPS ITU-T V.11 interface
          A.1.1 Interface signals
          A.1.2 Automatic cable delay compensation (optional)
          A.1.3 Serial communication channel
               A.1.3.1 Transmission characteristics
               A.1.3.2 Message structure
               A.1.3.3 Message contents
                    A.1.3.3.1 Time event message
                    A.1.3.3.3 GNSS status message
     A.2 1PPS 50 ( phase synchronization measurement interface
Appendix I  Time and phase noise sources in time distribution chains
     I.1 Noise introduced by a primary reference time clock (PRTC)
     I.2 Noise introduced by a packet master clock function
     I.3 Noise introduced by a packet slave clock function
     I.4 Noise introduced by a telecom transparent clock
     I.5 Noise introduced by a link
     I.6 Derivation of delay asymmetry
     I.7 Characteristics of the noise sources
          I.7.1 Reference time error
          I.7.2 PHY latency variation and asymmetry
          I.7.3 Timestamping granularity
          I.7.4 Local oscillator phase noise
          I.7.5 Frequency reference phase error
          I.7.6 Time transients
          I.7.7 Link asymmetry
          I.7.8 Error in distributing time inside a node
     I.8 Time error accumulation in a chain of clocks
Appendix II  Time and phase end application synchronization requirements
Appendix III  Asymmetry compensation for use of different wavelengths
Appendix IV  Link and network asymmetry compensation
Appendix V  Delay asymmetry resulting from interface rate change in PTP-unaware  network elements
Appendix VI  Time synchronization aspects in TDD based mobile communication systems
     VI.1 An overview of radio-interference in TDD systems
     VI.2 Signal frame format of TDD systems
     VI.3 Base station to base station interference
          VI.3.1 Downlink to uplink switching point
          VI.3.2 Uplink to downlink switching point
     VI.4 User equipment to user equipment interference
Appendix VII  Time scales
     VII.1 Time scales
     VII.2 Relationship between time scales
Bibliography