Kddi Corporation

Kddi Research, Inc.

Yasuhiro Suegara

Takeo Ohseki

Issei Kanno

Masahito Umehara

Hailan Peng

Kazuya Moriwaki

Noriyuki Hashimoto

Kouichiro Kitagawa

Masaya Shibayama

Fumio Watanabe

Xiaoqiu Wang

Masashi Fushiki

Kazuhide Toda

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 device selects, in a case where data that is to be transmitted to the base station device is generated, one setting for use in transmission of a scheduling request to a base station device, from among a plurality of settings that correspond to different combinations of a bandwidth, a time duration, and a periodicity and can be used in transmission of the scheduling request, and transmits the scheduling request to the base station device with use of the one setting that was selected.

Terminal device, base station device, control method, and storage medium for controlling the transmission of signals

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

There is provided a base station apparatus capable of transmitting a signal to a terminal apparatus and receiving an acknowledgement from the terminal apparatus. The base station apparatus transmits, to the terminal apparatus, information pertaining to a resource to be used to transmit the acknowledgement and determined in accordance with a length of a period from when the signal is transmitted to the terminal apparatus until the acknowledgement is received, and receives the acknowledgement transmitted by the terminal apparatus using the resource by specifying the resource based on the information.

Base station apparatus, terminal apparatus, communication method, and computer-readable storage medium

A communication apparatus, which is capable of performing, in a predetermined frequency band to be used by a first radio communication system configured to periodically transmit a reference signal with a predetermined frequency spacing, communication using a second radio communication system that is different from the first radio communication system, performs communication of the second radio communication system while the base station apparatus of the first radio communication system operates in a mode in which periodic transmission of the reference signal is stopped for a predetermined period, based on information relating to a timing at which a base station apparatus of the first radio communication system is to operate in the mode.

Communication apparatus, communication method, and computer-readable storage medium for implementing coexistence with legacy system

A communication device, which is capable of performing communication via a second wireless communication system that is different from a first wireless communication system, in a frequency band that is used by the first wireless communication system, the first wireless communication system periodically transmitting a reference signal, transmits, to a base station device of the first wireless communication system, information for operating the base station device in a mode in which the periodical transmission of the reference signal is interrupted for a predetermined period, and performs communication involving a predetermined signal of the second wireless communication system while the base station device of the first wireless communication system is operating in the mode.

Communication device, communication method, and storage medium for implementing coexistence with legacy system

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 terminal apparatus that performs communication using a communication path set between the terminal apparatus and a core network via a base station apparatus connected to the core network or via the base station apparatus and a relay apparatus that relays communication with the base station apparatus acquires information regarding candidates of a communication path to which switching should be performed from a first communication used, from the base station apparatus that functions as a serving base station in the first communication path, determines whether or not to perform switching of the communication path from the first communication path, and performs switching from the first communication path to a second communication path included in the candidates without being instructed by the serving base station, in response to the determination to perform the switching after receiving the information regarding the candidates.

Terminal apparatus and base station apparatus in wireless communication system in which handover including relay transmission path is executed, control method thereof, and storage medium

A terminal device that can be connected to one or more base station devices that each form one or more beams is described. The terminal device monitors, when the terminal device is not connected to any of the one or more base station devices, a connection target beam to be used when the terminal device establishes a connection with any of the one or more base station devices; and reports, at least based on a fact that the connection target beam has transitioned, information regarding the connection target beam to a base station device that forms the connection target beam. A base station device among the one or more base station devices to execute paging of the terminal device and a beam to be used in the paging are controlled based on the information regarding the connection target beam.

Terminal device, network device for exchanging information on selected beam

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.

Mobile communication system, terminal device, base station device, communication method, and computer program

Terminal device and network device for exchanging information on selected beam

A base station device (E-UTRAN) assigns a frequency band unsupported by the base station device as a radio resource usable for terminal-to-terminal communication, and transmits resource information for designating the assigned radio resource to a first terminal device and a second terminal device.

Growing community of inventors

Fujimino, Japan

Yasuhiro Suegara