US 12,452,739 B2
Fast return to 5G systems (5GS) after handover to evolved packet system (EPS) due to EPS fallback from 5GS
Changhong Shan, Cupertino, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Mar. 13, 2024, as Appl. No. 18/603,847.
Application 18/603,847 is a continuation of application No. 17/310,276, granted, now 11,937,132, previously published as PCT/US2020/015719, filed on Jan. 29, 2020.
Claims priority of provisional application 62/798,303, filed on Jan. 29, 2019.
Prior Publication US 2024/0259885 A1, Aug. 1, 2024
Int. Cl. H04W 36/00 (2009.01); H04W 36/14 (2009.01); H04W 36/26 (2009.01)
CPC H04W 36/0022 (2013.01) [H04W 36/0055 (2013.01); H04W 36/14 (2013.01); H04W 36/26 (2013.01); H04W 36/00226 (2023.05); H04W 36/0064 (2023.05); H04W 36/1446 (2023.05)] 20 Claims
OG exemplary drawing
 
1. A method for managing a fast return of a user equipment (UE) to one or more 5G systems (5GS) after handover to an Evolved Packet System (EPS) from the one or more 5GS, the method comprising:
determining, by a base station (BS), whether to initiate a fallback procedure for the UE to connect the UE to the EPS to transfer a voice signal based on no presence of quality of service (QOS) flow for the voice signal to the UE being detected;
based on determining that the fallback procedure is initiated, receiving, by the BS and from the UE, a measurement report identifying an evolved universal terrestrial radio access network (E-UTRAN) connected to the EPS, to handover the UE to;
based on the measurement report, initiating, by the BS, a handover of the UE to the EPS via the E-UTRAN, including transmitting an indication of a last used 5GS public land mobile network identification (PLMN-ID) to one or more other BSs for storage by the one or more other BSs throughout a connection of the UE to the EPS; and
after termination of the voice signal, re-establishing, by the BS and via the one or more other BSs, a connection with the UE to connect the UE to the one or more 5GS based on the last used 5GS PLMN-ID.