# US 11,310,754 B2 · Nodes and methods for determining and enabling a synchronized time reference in a wireless communications network > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,310,754 B2 - Document ID: US11310754B2 - Status: Granted - Kind: B2 - Application number: 16/765,761 - Filed: 2017-11-20 - Published: 2020-12-03 - Granted: 2022-04-19 - Earliest claimed: 2017-11-20 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Junghoon Kim; Hyunsoo Kim; Mikael Olofsson - Web page: https://patentgrep.com/patent/US11310754B2 ## CPC - H04W 56/00: Synchronisation arrangements - H04W 56/0015: {one node acting as a reference for the others} - H04B 7/18513: {Transmission in a satellite or space-based system} - H04W 56/002: {Mutual synchronization} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract A method performed by a first network node (110) for determining a synchronized time reference in a wireless communications network (100) is provided. The first network node (110) determine a first timing reference (t3) by detecting a broadcasted time reference signal (S1). Also, the first network node (110) receive information indicating a first timing difference (Δt21−22) between a second timing reference (t21) that is based on a detection of the broadcasted time reference signal (S1) at a second network node (111) and a third timing reference (t22) that is based on a positioning signal (S2) received by the second network node (111). Then, the first network node (110) determine a time reference for the first network node (110) based on the determined first timing reference (t3) and the received first timing difference (Δt21−22). A first network node (110) for determining a timing reference in a wireless communications network (100) is also provided. Furthermore, a second network node (111) and a method performed therein for enabling a synchronized time reference in a wireless communications network (100) are also provided. ## Claims ### Claim 1 A method performed by a first network node for determining a synchronized time reference in a wireless communications network, the method comprising: determining a first timing reference by detecting a broadcasted time reference signal transmitted from a transmitter of a LORAN-C, eLORAN, DCF77, or Chayka system; receiving information indicating a first timing difference and at least a second timing difference, wherein the first timing difference is between a second timing reference that is based on a detection of the broadcasted time reference signal at a second network node and a third timing reference that is based on a positioning signal received by the second network node, and the second timing difference is between at least a fourth timing reference determined by at least a third network node by detecting the broadcasted time reference signal at the at least third network node, and at least a fifth timing reference based on the positioning signal received by the at least third network node; and determining a synchronized time reference for the first network node based on the determined first timing reference and a third timing difference, wherein the third timing difference is determined based on a weighted average of the first and the at least second timing difference indicated in the received information, wherein the weighted average is further based on corresponding distances of the second network node and the at least third network node to the first network node. ### Claim 2 (depends on 1) The method according to claim 1, wherein the determining a synchronized time reference for the first network node is further based on a first relative time difference between detection of the broadcasted time reference signal at the first network node and detection of the broadcasted time reference signal at the second network node. ### Claim 3 (depends on 1) The method according to claim 1, wherein the determining a synchronized time reference for the first network node is further based on at least a second relative time difference between detection of the broadcasted time reference signal at the first network node and detection of the broadcasted time reference signal at the at least third network node. ### Claim 4 (depends on 1) The method according to claim 1, further comprising assigning a first distance an equal or higher weight in the weighted average than a second distance when the first distance is equal to or shorter than the second distance. ### Claim 5 (depends on 3) The method according to claim 3, further comprising determining the second relative time difference based on information about the location of the first network node, the location of the transmitter of the broadcasted time reference signal, and the location of the at least third network node. ### Claim 6 (depends on 1) The method according to claim 1, wherein the broadcasted time reference signal is a signal having a frequency located in a range of about 50-100 kHz, and the positioning signal is a global positioning signal. ### Claim 7 A first network node for determining a synchronized time reference in a wireless communications network, the first network node being configured to: determine a first timing reference by detecting a broadcasted time reference signal transmitted from a transmitter of a LORAN-C, eLORAN, DCF77, or Chayka system; receive information indicating a first timing difference and at least a second timing difference, wherein the first timing difference is between a second timing reference that is based on a detection of the broadcasted time reference signal at a second network node and a third timing reference that is based on a positioning signal received by the second network node, and the second timing difference between at least a fourth timing reference determined by at least a third network node by detecting the broadcasted time reference signal at the at least third network node, and at least a fifth timing reference based on the positioning signal received by the at least third network node; and determine a synchronized time reference for the first network node based on the determined first timing reference and a third timing difference, wherein the third timing difference is determined based on a weighted average of the first and the at least second timing difference indicated in the received information, wherein the weighted average is further based on corresponding distances of the second network node and the at least third network node to the first network node. ### Claim 8 (depends on 7) The first network node according to claim 7, further configured to determine the synchronized time reference based on a first relative time difference between detection of the broadcasted time reference signal at the first network node and detection of the broadcasted time reference signal at the second network node. ### Claim 9 (depends on 7) The first network node according to claim 7, further configured to determine the synchronized time reference based on at least a second relative time difference between detection of the broadcasted time reference signal at the first network node and detection of the broadcasted time reference signal at the at least third network node. ### Claim 10 (depends on 7) The first network node according to claim 7, further configured to assign a first distance an equal or higher weight in the weighted average than a second distance when the first distance is equal to or shorter than the second distance. ### Claim 11 (depends on 8) The first network node according to claim 8, further configured to determine the first relative time difference based on information about the location of the first network node, the location of the transmitter of the broadcasted time reference signal, and the location of the second network node. ### Claim 12 (depends on 9) The first network node according to claim 9, further configured to determine the second relative time difference based on information about the location of the first network node, the location of the transmitter of the broadcasted time reference signal, and the location of the at least third network node. ### Claim 13 (depends on 7) The first network node according to claim 7, wherein the broadcasted time reference signal is a signal having a frequency located in a range of about 50-100 kHz, and the positioning signal is a global positioning signal. ### Claim 14 (depends on 7) The first network node according to claim 7, comprising a processor and a memory, wherein the memory includes instructions executable by the processor.