	US 11,997,628 B2
	Advanced frequency synchronization in a mobile integrated access backhaul deployment
Ilkka Antero Keskitalo, Oulu (FI); Esa Tapani Tiirola, Oulu (FI); Esa Mikael Malkamäki, Espoo (FI); Juha Sakari Korhonen, Espoo (FI); and Keeth Saliya Jayasinghe Laddu, Espoo (FI)
Assigned to NOKIA TECHNOLOGIES OY, Espoo (FI)
Appl. No. 17/785,204
Filed by NOKIA TECHNOLOGIES OY, Espoo (FI)
PCT Filed Dec. 1, 2020, PCT No. PCT/EP2020/084074 § 371(c)(1), (2) Date Jun. 14, 2022, PCT Pub. No. WO2021/144059, PCT Pub. Date Jul. 22, 2021.
Claims priority of provisional application 62/960,358, filed on Jan. 13, 2020.
Prior Publication US 2022/0400458 A1, Dec. 15, 2022
Int. Cl. H04W 56/00 (2009.01)

CPC H04W 56/0035 (2013.01) [H04W 56/001 (2013.01); H04W 56/004 (2013.01)]

19 Claims

1. An apparatus, comprising:

at least one processor; and

at least one memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to:

estimate a change in a propagation delay at two time instants;

measure a time period of the two time instants using a local clock of a network node, wherein the two time instants correspond to a known timing of a received signal;

subtract the change in the propagation delay from a measured time period Δt;

calculate a difference between a subtracted time period and the known timing of the received signal; and

convert the difference to a frequency offset value Δf to synchronize downlink transmission frequency between the network node and a parent node.