US 12,323,937 B2
Frequency offset estimation method for average consistency clock synchronization
Heng Wang, Chongqing (CN); Liuqing Chen, Chongqing (CN); and Pengfei Gong, Chongqing (CN)
Assigned to Chongqing University Of Posts And Telecommunications, Chongqing (CN)
Appl. No. 17/617,936
Filed by Chongqing University Of Posts And Telecommunications, Chongqing (CN)
PCT Filed Nov. 15, 2019, PCT No. PCT/CN2019/118864
§ 371(c)(1), (2) Date Dec. 10, 2021,
PCT Pub. No. WO2021/056761, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 201910900255.6 (CN), filed on Sep. 23, 2019.
Prior Publication US 2022/0369258 A1, Nov. 17, 2022
Int. Cl. H04W 56/00 (2009.01); H04J 3/06 (2006.01); H04L 25/02 (2006.01); H04L 27/00 (2006.01)
CPC H04W 56/005 (2013.01) [H04J 3/0638 (2013.01); H04L 25/024 (2013.01); H04L 27/0014 (2013.01); H04W 56/001 (2013.01); H04L 2027/0026 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A frequency offset estimation method for average consensus-based clock synchronization, specifically comprising following steps:
S1: assuming that each node i in a network periodically broadcasts a local clock message τi(tli), receiving, by a neighbor node j thereof, the clock message, recording a current local clock τj(tlid) of the neighbor node, so the neighbor node establishes a relative clock relationship according to known local clock information and time delay:
τj(tlid)=ωij(tli)+φij+dijf+dijr(tli)
where ωij and φij respectively represent a relative frequency offset and a relative phase offset of the node i with respect to the node j, dijr(tli) represents random communication time delay satisfying truncated exponential distribution of which an average value is λ and an upper limit is D; dijf represents fixed time delay existing in a data packet transmission process;
S2: performing relative frequency offset estimation according to the relative clock relationship after the neighbor node j receives synchronization messages each cycle, wherein the node j receives L synchronization messages from the node i, the relative frequency offset ωij between nodes is estimated using a maximum likelihood estimation method:

OG Complex Work Unit Math
where θij=φij+dijf.