US 11,997,546 B2
RLF handling during multi-connectivity handover
Candy Yiu, Portland, OR (US); Yi Guo, Shanghai (CN); Kyeongin Jeong, Dongwon (KR); and Oluwaseyi Omotere, Houston, TX (US)
Assigned to Apple Inc., Cupertino, CA (US)
Appl. No. 17/275,830
Filed by Apple Inc., Cupertino, CA (US)
PCT Filed Sep. 23, 2019, PCT No. PCT/US2019/052401
§ 371(c)(1), (2) Date Mar. 12, 2021,
PCT Pub. No. WO2020/068651, PCT Pub. Date Apr. 2, 2020.
Claims priority of provisional application 62/736,994, filed on Sep. 26, 2018.
Prior Publication US 2022/0046487 A1, Feb. 10, 2022
Int. Cl. H04W 36/00 (2009.01); H04W 74/0833 (2024.01); H04W 76/19 (2018.01)
CPC H04W 36/0027 (2013.01) [H04W 74/0833 (2013.01); H04W 76/19 (2018.02)] 20 Claims
OG exemplary drawing
 
1. An apparatus of a user equipment (UE), the apparatus comprising:
processing circuitry, wherein to configure the UE for radio link failure (RLF) handling during a multi-connectivity handover with a source base station (SBS) and a target base station (TBS), the processing circuitry is to:
encode a measurement report for transmission to the SBS via a first communication link, the measurement report triggered based on a measurement event configured by the SBS;
decode radio resource control (RRC) signaling from the SBS, the RRC signaling including a handover command in response to the measurement report, the handover command including an indication for multi-connectivity support by the SBS and the TBS during the handover;
based at least in part on the handover command including the indication for multi-connectivity support, perform a random access channel (RACH) procedure with the TBS using a second communication link between the UE and the TBS while maintaining the first communication link with the SBS; and
perform radio link monitoring (RLM) on the first communication link and the second communication link during the handover, wherein to perform RLM on the first communication link and the second communication link the processing circuitry is to:
start a first RLF timer upon detecting a number of out-of-sync signals associated with the first communication link; and
start a second RLF timer upon detecting a number of out-of-sync signals associated with the second communication link;
declare an RLF on the first communication link upon expiration of the first RLF timer; and
declare an RLF on the second communication link upon expiration of the second RLF timer; and
memory coupled to the processing circuitry and configured to store the handover command with the indication.