Kddi Corporation

Masahito Umehara

Takeo Ohseki

Yasuhiro Suegara

Issei Kanno

A terminal comprises a function capable of operating in a plurality of states that include a first state in which a connection with a base station has been established, and a second state in which a connection with a base station has not been established, but the base station holds information regarding the terminal device. After starting operation in the second state from a state in which the terminal operates with a first base station in the first state, if predetermined information that enables communication with the first base station in the second state and that has been acquired from the first base station in the first state is held, the terminal determines whether a signal transmission target has changed from the first base station to a second base station device, and performs communication according to a result of the determination.

Enabling a terminal device to perform efficient communication in a stand-by state

A terminal apparatus, which executes a two-step random access procedure or a four-step random access procedure to establish a connection with a base station apparatus, executes control such that, in a case where a first message of the two-step random access procedure including a preamble and predetermined information for connection establishment is transmitted and a number of unsuccessful attempts to receive the first message by the base station apparatus exceeds a predetermined number, the terminal apparatus transmits a second message to be transmitted from the terminal apparatus to the base station apparatus in the four-step random access procedure.

Terminal apparatus, base station apparatus, control method, and computer-readable storage medium for executing random access procedure

Terminal device that performs communication in stand-by state, method for controlling the same, and computer-readable storage medium

A terminal apparatus, which is able to establish a connection with a base station apparatus via a two-step random access procedure by transmitting a first signal including a random access preamble and predetermined information to the base station apparatus and receiving a second signal as a reply to the first signal from the base station apparatus, acquires a random access-radio network temporary identifier (RA-RNTI) on the basis of a radio resource having been used to transmit the predetermined information with the first signal, and executes reception processing of the second signal using the RA-RNTI.

A base station device transmits a control signal for causing a transition from an RRC_CONNECTED state to an RRC_INACTIVE state and including connection parameter information to a terminal device. The terminal device performs uplink transmission to the base station device using the connection parameter information included in the control signal in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned. The base station device performs uplink reception from the terminal device that is in the RRC_INACTIVE state to which the RRC_CONNECTED state has transitioned using the connection parameter information included in the control signal.

Growing community of inventors

Tokyo, Japan

Masahito Umehara