US 11,800,474 B2
Methods, second node and apparatus for determining clock asynchronization
Satyam Dwivedi, Sollentuna (SE); Fredrik Gunnarsson, Linkoping (SE); Avneesh Vyas, Sundbyberg (SE); and Magnus Sandgren, Staffanstorp (SE)
Assigned to Telefonaktiebolaget LM Ericsson (Publ), Stockholm (SE)
Appl. No. 17/278,522
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Sep. 27, 2018, PCT No. PCT/SE2018/050990
§ 371(c)(1), (2) Date Mar. 22, 2021,
PCT Pub. No. WO2020/067941, PCT Pub. Date Apr. 2, 2020.
Prior Publication US 2022/0039042 A1, Feb. 3, 2022
Int. Cl. H04W 56/00 (2009.01)
CPC H04W 56/0035 (2013.01) [H04W 56/001 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A method for determining asynchronization between a first clock used by a first node and a second clock used by a second node, the method comprising:
measuring a sequence of time differences based on a sequence of signals periodically sent by the second node and received by the first node, each time difference of a signal being between a respective transmission timestamp in accordance with the second clock and a respective receiving timestamp in accordance with the first clock; and
estimating at least one of a relative phase offset and a relative frequency offset between the first and the second clock based on the sequence of time differences, the estimating comprising:
using a model function to obtain ansatz waveforms by providing the model function with different input values of a relative phase offset parameter and a relative frequency offset parameter;
using an objective function to determine optimal input values among the different input values, wherein the ansatz waveform obtained with the optimal input values corresponds most closely to the sequence of time differences; and
using the optimal input values of the relative phase offset parameter and the relative frequency offset parameter as the estimated relative phase offset and relative frequency offset.