US 12,273,834 B2
Neighbor cell synchronization upon state transition
Oumer Teyeb, Montréal (CA); Sebastian Lindqvist, Norrköping (SE); Sangwook Han, Kyeonggi (KR); Patrik Rugeland, Stockholm (SE); and Icaro L. J. Da Silva, Solna (SE)
Assigned to Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
Appl. No. 17/618,288
Filed by Telefonaktiebolaget LM Ericsson (publ), Stockholm (SE)
PCT Filed Jun. 12, 2020, PCT No. PCT/SE2020/050609
§ 371(c)(1), (2) Date Dec. 10, 2021,
PCT Pub. No. WO2020/251466, PCT Pub. Date Dec. 17, 2020.
Claims priority of provisional application 62/861,996, filed on Jun. 14, 2019.
Prior Publication US 2022/0312354 A1, Sep. 29, 2022
Int. Cl. H04W 76/27 (2018.01); H04W 56/00 (2009.01); H04W 52/02 (2009.01)
CPC H04W 56/002 (2013.01) [H04W 76/27 (2018.02); H04W 52/0209 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method of establishing or resuming a connection implemented by a user equipment (UE), the method comprising:
initiating, while in a power saving state, a connection procedure to establish or resume the connection in a primary cell;
synchronizing, prior to receiving a message requiring synchronization with a target cell other than the primary cell, with one or more candidate cells selected by the UE in addition to the primary cell to obtain early synchronization information;
receiving, from the network, the message requiring synchronization with the target cell other than the primary cell;
determining that the target cell is among the candidate cells for which early synchronization information is available;
responsive to determining that the target cell is one of the candidate cells for which synchronization is established, transmitting a random access preamble to the target cell using the early synchronization information;
configuring a timer to control the synchronization with one or more of the candidate cells;
starting the timer when the UE initiates synchronization with one of the candidate cells;
stopping the timer when the message requiring synchronization with a target cell is received; and
maintaining synchronization with the cell associated with the timer while the timer is running.