US 12,323,871 B2
Terminal apparatus, base station apparatus, and method
Takako Hori, Sakai (JP); Shohei Yamada, Sakai (JP); and Hidekazu Tsuboi, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Appl. No. 17/792,760
Filed by Sharp Kabushiki Kaisha, Sakai (JP)
PCT Filed Jan. 14, 2021, PCT No. PCT/JP2021/001015
§ 371(c)(1), (2) Date Jul. 14, 2022,
PCT Pub. No. WO2021/149579, PCT Pub. Date Jul. 29, 2021.
Claims priority of application No. 2020-007312 (JP), filed on Jan. 21, 2020.
Prior Publication US 2023/0040867 A1, Feb. 9, 2023
Int. Cl. H04W 4/00 (2018.01); H04W 36/00 (2009.01); H04W 36/30 (2009.01); H04W 48/20 (2009.01)
CPC H04W 36/305 (2018.08) [H04W 36/0079 (2018.08); H04W 48/20 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A terminal apparatus that communicates with a base station apparatus, the terminal apparatus comprising:
a receiver configured to receive, from the base station apparatus, a Radio Resource Control (RRC) reconfiguration message; and
a processor configured to perform configuration in accordance with the RRC reconfiguration message, wherein
in a case that (i) a first timer of an RRC protocol expires, (ii) a radio link failure in a source primary cell is not detected, (iii) a first configuration is included in the RRC reconfiguration message, and (iv) the first configuration is performed for the terminal apparatus, the processor
stops all timers configured for a Radio Link Control (RLC) entity of a Signaling Radio Bearer (SRB) in the source primary cell,
resumes the SRB suspended in the source primary cell, and
transmits an RRC message for notifying the base station apparatus that Dual Active Protocol Stack (DAPS) handover has failed,
the first configuration is a configuration related to a radio bearer to which the DAPS handover is applied, and
the first timer starts in a case that the terminal apparatus receives, from the base station apparatus, an RRC message including an information element indicating change of a serving cell in an RRC connected state, and stops in a case that a random access to a Special Cell (SpCell) succeeds.