P3 Common-Vew Technque n Synchronzaton Networ Perormance Montorng or LTE-A and 5G NR Sammy Su, Y. J. Huang, C. Y. Chu, and C. S. Lao Natonal Standard Tme and Frequency Lab. Telecommuncaton Laboratores, Chunghwa Telecom Co., Ltd., TAIWAN
Hstory o the Prmary Reerence (Tme) Cloc G.8 (988) PRC G.8 (997) PRC G.87 (0) PRTC G.87. (06) eprtc G.87./Y.367. eprtc unctonal model
ITU-T Prmary Reerence Tme Cloc (PRTC) Classes ITU-T eprtc/prtc Tme error Holdover PRTC (ITU-T G.87) eprtc (ITU-T G.87.) PRTC-A (Rename PRTC) +/- 00ns Further study PRTC-B* +/- 40ns Further study eprtc-a* wth Cs (eprc) eprtc-b* wth Cs(s) (eprc) +/- 30ns +/- 30ns +/- 00ns over 4 days +/- 00ns over 80days L (C/A code) L C/A code wth L/LC carrer phase** L C/A code (or wth L/LC carrer phase) L C/A code (or wth L/LC carrer phase) *Cable delay compensaton usng Two Way Tme Transer (Layer -TWTT) (Opton). **L=575.4MHz, L=7.7MHz eprtc: enhanced PRTC eprc: enhanced Prmary Reerence Cloc Both eprtc-a/b and PRTC-A/B consttute the networ synchronzaton or accuracy requency, tme and phase to ulll the needs o both servce and nrastructure. 3
Hgh Level Archtecture For Accurate and Precse Tme/Phase Dstrbuton For LTE-TDD/LTE-A(FDD,TDD) and 5G NR G.87. eprtc ( eprc(cs)) Fronthaul (ecpri Spec. V.) UTC Frequency +Tme/Phase eprtcs (Core level) UTC level Metrology Insttutes Carrer () Moble Bachaul Sync-E, PTP e.g., enode B ecpri (erec, ere) BIPM/UTC Natonal Tme Standard UTC(*) OTT PRTC-A/B (APTS +AAC) OTT PRTC-A/B (APTS+AAC) Common-vew Servce (G.87) Carrer (n) Moble Bachaul Sync-E, PTP UTC Frequency +Tme/Phase eprtcs (Core level) e.g., enode B ecpri (erec, ere) Synchronzaton networ supervson and measurement ( wth Bg-Data and AI Support ) G.87. eprtc (eprc(cs)) () Full Tmng Support (FTS), or () Partal Tmng support (PTS), wth Asssted Partal Tmng Support (APTS) and AAC. Synchronzaton networ supervson and measurement Drect measurement method: common-vew allows < 0ns Tme Transer or measurement reerence: () IEEE 588 Hgh accuracy (Whte Rabbt) allows a ew ns () Optcal Tme Transer (OTT) allows a ew 00 ps Advanced Synchronzaton Networ Management : Bg-Data, and AI ncludng Knowledge-base Support BIPM: Bureau Internatonal des Pods et Mesures UTC: Coordnated Unversal Tme : Global Navgaton Satellte System Cs: Cesum Cloc PTP: Precson Tme Protocol Sync-E: Synchronous Ethernet CPRI: Common Publc Rado Interace REC: Rado Equpment Controllers RE: Rado Equpment AAC : Automatc Asymmetry Compensaton 4 4
PRTCs-Cloud and Perormance Montorng Based on Common-vew Technque n Telecommuncaton Networs PRTC-B PRTC-B TWTT Antenna* eprtc-a Core Center (3) eprtc-a Core Center () PRTC-B eprtc-a eprtc-a Core Center () PRTC-B** PTP Flow PRTC-A UTC level Metrology Insttutes UTC(*) Natonal Tme and Frequency Standard Lab.(UTC(*)) *TWTT: two way tme transer antenna PRTC-B eprtc-a Core Center () Core Center (- ) PTP Flow PRTC-B PRTC-B eprtc-a PTP Flow Core Center (-) PRTC-A PRTC-B PRTC-A **Usng PTP rom the Core eprtc (A,B) to bac up the Edge PRTC(A,B), when the later s unavalable. The PTP accumulates tme error ( cte, dte) as t traverses the networ, where the dte created by the PDV and the cte created by delay asymmetry n the networ. For stable delay asymmetry, t can be calbrated n advance or compensaton. n advance or compensaton. 5
Usng PTP From The Core eprtc To Bac Up the Edge PRTC Fronthaul Networ Fronthaul Networ PRTC- B Hgh accuracy requency nput rom eprtc-a/b to stablze the cloc n PRTC- B/PRTC-A. PRTC- B eprc Cs Cs Core-level eprtc-(a, B) PRTC- B PRTC- B PTP low PTP connectons rom the Core eprtc to the Edge PRTC PRTC- B APTS+AAC PTP slave evaluatng PTP connecton asymmetry Fronthaul Networ (Sync-E & PTP) IEEE 80.CM & G.87. Tme Senstve Networ Fronthaul Networ Fronthaul Networ Traceable requency phase drt (Tme Hold-over) Frequency (eprc) 0ns 50ns 00ns us <.0E- >.8 h > 3.9 h > 7.8 h >.6 days 6
Consderaton o Desgn a Relable Sync. Networ (req., tme/phase). Relablty e.g. to overcome outages and jammng => Should be not too much dependent, s used => a bac up s need (e.g., eprtc(a, B)). Permanent supervson and measurement => requres better reerence clocs and better tme transer* 3. Avalablty e.g., AAC (Automatc Asymmetry Compensaton) 4. Advanced synchronzaton networ management => Bg-Data, and AI ncludng Knowledge-base Support *Synchronzaton networ supervson and measurement Drect measurement method: Common-Vew Technque allows < 0ns Tme Transer or measurement reerence: () IEEE 588 Hgh accuracy (Whte Rabbt) allows a ew ns () Optcal Tme Transer (OTT) allows a ew 00ps 7
PRTCs Tme/Phase montorng based on (e.g., GPS) Common-vew technque Satellte S e.g., GPS( ) Ionosphere Propagaton delay Troposphere Cloc A SA Data low SB Cloc B Propagaton delay 000m Tme error TE A Earth Tme error TE B () GPS eprtc B GPS UTC SA Natonal Tme and Frequency Standard Lab. SB eprtc locates n Core Center() K=,,3,---N The nal measurement result s: ( UTC(*) eprtc ( B )) ( SA SB ) Tme /phase doman 8
9 ε n c c T I L ε n c c T I L c c T I P c c T I P The code and phase models are descrbed as ollows: ) ( 3 P P P ) ( 3 L L L The onosphere-ree P code P 3 and carrer phase L 3 are modeled as: Code and Phase models
Global Navgaton Satelltes System e.g., GPS( ) S e.g., GPS( l) UTC(TL) Carrer OSS(s) e.g., eprtc/prtc pps UTC(TL) Common-vew servce OSS Natonal Tme and Frequency Standard Lab. UTC(*) A Data nput Common-vew Engne TE A eprc(cs) 0MHz B eprtc Remote CalbratonCore Center (-) pps PTP over Ethernet Common-vew Engne TE( B K ) TE( BK ) eprc(cs) 0MHz B eprtc Remote Calbraton Core Center () pps PTP over Ethernet Common-vew Engne The conguraton o (e.g., GPS) common-vew servces deployment n the networ, where A ste locates n Natonal Tme and Frequency Standard Lab. and B stes locate n core centers n carrer networ GPS: Global Postonng System OSS: Operatons support systems 0
Setup or testng eprtc eprtc(dut)
Warmup Test o eprtc 5 0 - UTC(TL)-ePRTC-ns * UTC-UTC(TL) 5 0 *4.7ns *3.7ns -5-0 -5-0 -5-30 5837 5838 5839 5830 583 583 5833 5834 5835
Measurement results (UTC(TL)-ePRTC)+K 3
eprtc stablty: MTIE 4
eprtc stablty: TDEV 5
eprtc Tme Holdover 6
Conclusons The analytcal results justy the common-vew technque oers a eectve perormance montorng schemes or eprtcs-cloud n synchronzaton networ the remote calbraton scheme elmnates the constant tme error (cable delay compensaton) generated n eprtc mnmze the tme error generated by eprtc Expectably, the common-vew servce wll be wdely used n synchronzaton networ n the carrers or 4G (e.g., LTE-A), the comng uture 5G, and the Deense Oce Department (DoD) n a country to secure tme 7