US 12,133,128 B2
Terminal apparatus and communication method
Takako Hori, Sakai (JP); Shohei Yamada, Sakai (JP); and Hidekazu Tsuboi, Sakai (JP)
Assigned to SHARP KABUSHIKI KAISHA, Sakai (JP)
Appl. No. 17/764,477
Filed by Sharp Kabushiki Kaisha, Sakai (JP)
PCT Filed Sep. 29, 2020, PCT No. PCT/JP2020/036891
§ 371(c)(1), (2) Date Mar. 28, 2022,
PCT Pub. No. WO2021/065903, PCT Pub. Date Apr. 8, 2021.
Claims priority of application No. 2019-179891 (JP), filed on Sep. 30, 2019.
Prior Publication US 2022/0345962 A1, Oct. 27, 2022
Int. Cl. H04W 36/00 (2009.01); H04W 36/14 (2009.01); H04W 76/19 (2018.01)
CPC H04W 36/0079 (2018.08) [H04W 36/144 (2023.05); H04W 76/19 (2018.02); H04W 36/0022 (2013.01)] 2 Claims
OG exemplary drawing
 
2. A communication method for a terminal apparatus for communicating with a base station apparatus, the communication method comprising the steps of:
receiving, from the base station apparatus, a message indicating handover from a first Radio Access Technology (RAT) to a second RAT; and
in a case that processing of the handover in accordance with the message fails,
attempting to select a cell in the second RAT based on that a first condition is fulfiled and first information is included in the message, and
reverting back to a configuration used in a primary cell in the first RAT and performing a connection re-establishment procedure based on that the first condition is fulfilled and the first information is not included in the message, or that a second condition is fulfilled, wherein
the first condition is a failure in establishing a connection to the second RAT, and
the second condition is that the terminal apparatus is unable to comply with any part of a configuration included in the message, and
the first information is information indicating an Evolved Packet System (EPS) fallback for an Internet Protocol (IP) Multimedia Subsystem (IMS) voice service.