US 12,464,569 B2
Terminal apparatus, and control method for performing handover having enhanced communication efficiency
Hiroki Takeda, Tokyo (JP); Yanwei Li, Tokyo (JP); Jungyeon Hong, Fujimino (JP); Yoshitaka Takaku, Tokyo (JP); and Takeo Ohseki, Fujimino (JP)
Assigned to KDDI CORPORATION, Tokyo (JP)
Filed by KDDI CORPORATION, Tokyo (JP)
Filed on Jan. 13, 2025, as Appl. No. 19/018,124.
Application 19/018,124 is a continuation of application No. PCT/JP2024/003678, filed on Feb. 5, 2024.
Claims priority of application No. 2023-019287 (JP), filed on Feb. 10, 2023.
Prior Publication US 2025/0151122 A1, May 8, 2025
Int. Cl. H04W 74/0833 (2024.01); H04W 72/23 (2023.01); H04W 76/38 (2018.01)
CPC H04W 74/0833 (2013.01) [H04W 72/23 (2023.01); H04W 76/38 (2018.02)] 13 Claims
OG exemplary drawing
 
1. A terminal apparatus comprising:
a receiving unit configured to receive, from a currently connected base station apparatus, a setting of a radio resource control (RRC) layer for another base station apparatus that is a destination candidate for a handover by the terminal apparatus from the base station apparatus and to receive, from the base station apparatus, a physical downlink control channel (PDCCH) order instructing the terminal apparatus to transmit a random access preamble to the other base station apparatus without handover to the other base station apparatus being performed;
a transmitting unit configured to transmit the random access preamble to the other base station apparatus according to the instruction; and
a performing unit configured to perform handover to the other base station apparatus in a case where a command instructing for a handover to the other base station apparatus is received from the base station apparatus,
wherein the receiving unit receives, from the base station apparatus, a sequence unique to the terminal apparatus used by the terminal apparatus when generating the random access preamble and information for identifying radio resources that can be used when transmitting the random access preamble, and
the transmitting unit generates the random access preamble using the sequence unique to the terminal apparatus and transmits the random access preamble using radio resources identified via the information, and in a case where a signal requesting for retransmission of the random access preamble is received from the base station apparatus, the transmitting unit retransmits the random access preamble, and in a case where a signal requesting for retransmission of the random access preamble is not received from the base station apparatus or the other base station apparatus, the transmitting unit does not retransmit the random access preamble.