US 12,438,633 B2
Method of high precision time synchronization with a communication network grandmaster for user plane function
Liang Xia, Shatin (HK); Jianjun Zhang, Shatin (HK); Wei Li, Shatin (HK); and Liang Dong, Tai Po (HK)
Assigned to Hong Kong Applied Science And Technology Research Institute Co., Ltd, Shatin (HK)
Filed by Hong Kong Applied Science And Technology Research Institute Co., Ltd., Shatin (HK)
Filed on Feb. 16, 2023, as Appl. No. 18/110,594.
Prior Publication US 2024/0283555 A1, Aug. 22, 2024
Int. Cl. H04J 3/06 (2006.01); H04W 56/00 (2009.01)
CPC H04J 3/0667 (2013.01) [H04W 56/0015 (2013.01)] 20 Claims
OG exemplary drawing
 
20. A Data Plane Clock Servo module in a UPF module for synchronizing a Network-Side Time-Sensitive Networking (TSN) Translator (NW-TT) module inside a User Plane Function (UPF) of a communication network with a Grandmaster (GM) in a Time Domain of the communication network, the Data Plane Clock Servo module comprising:
a memory storing machine-readable instructions; and
a processor for executing the machine-readable instructions such that, when the processor executes the machine-readable instructions, it configures the Data Plane Clock Servo module comprising:
a first module for receiving a first time offset value (OffsetN3) between the GM and a UPF N3 interface or a second time offset value (OffsetNW-TT) between the UPF N3 interface and the NW-TT module, the first time offset value (OffsetN3) being determined from one or more Precision Time Protocol (PTP) or Generalized Precision Time Protocol (gPTP) messages received at the N3 interface, and the second time offset value (OffsetNW-TT) being determined from a hardware clock of the NW-TT module and a synchronized clock of the UPF N3 interface;
a second module for determining if the received first time offset value (OffsetN3) or second time offset value (OffsetNW-TT) is greater than a predetermined, calculated, or selected time period;
a Data Plane Clock Filter comprising a moving average filter which, upon receiving the first time offset value (OffsetN3) or the second time offset value (OffsetNW-TT), smooths the received first time offset value (OffsetN3) or second time offset value (OffsetNW-TT) to attenuate impulse noise to generate a smoothed clock offset output for the Data Plane Clock Offset Controller;
a Data Plane Proportional-integral (PI) Controller for receiving the smoothed clock offset output for the received first time offset value (OffsetN3) or second time offset value (OffsetNW-TT) to produce a fractional tick-rate adjustment u(t) value which coordinates the UPF N3 interface time with the GM tie or coordinates the NW-TT module time with the UPF N3 interface time; and
a Data Plane Clock Frequency Adjuster for receiving the fractional tick-rate adjustment u(t) value for the UPF N3 interface or the NW-TT module to adjust the respective clock frequency accordingly;
wherein the Data Plane Clock Offset Controller receives the smoothed clock offset output and adjusts the timing of the UPF N3 interface or the timing of the NW-TT module.