Electronics and Telecommunications Research Institute

Kt Corporation

You Sun Hwang

Ae Soon Park

Nam Hoon Park

Hyeong Jun Park

Kwang Ryul Jung

Mi Jeong Yang

Jae Sheung Shin

Hyung Deug Bae

Soon Yong Lim

Aesoon Park

Kyung Yul Cheon

Moon Soo Jang

Hye Yeon Kwon

Kyung-Yul Cheon

A method for setting synchronization between terminals performing device-to-device (D2D) communication based on a cellular communication system is disclosed. The method for setting synchronization between terminals includes receiving a message instructing synchronization setting with an opposite terminal from a base station, selecting a first preamble transmitted for a synchronization setting with the opposite terminal based on the message instructing synchronization setting, transmitting the selected first preamble to the opposite terminal, receiving a second preamble from the opposite terminal, and setting the synchronization with the opposite terminal using a reception timing of the second preamble when the second preamble is a preamble designated in the message instructing synchronization setting. Thus, when the present invention is used, synchronization between two terminals performing direct communication may be set using a physical layer random access channel resource which has been used in an existing mobile communication system.

Method for setting synchronization between device-to-device communication terminals based on cellular communication system

A method of providing service continuity between cellular communication and device-to-device communication is disclosed. A procedure for switching between cellular communication and device-to-device communication according to an example embodiment of the present invention may include transferring, by a gateway, a D2D bearer creation request message to an MME, transferring, by the MME, the D2D bearer creation request message to a base station, mapping, by the base station, D2D bearer QoS to D2D radio bearer QoS and transmitting an RRC connection reconfiguration message to terminals, receiving, by the base station, an RRC connection reconfiguration completion message indicating creation of a D2D radio bearer from the terminals, transmitting, by the base station, a D2D bearer creation response message indicating creation of a D2D bearer to the MME, and transferring, by the MME, the D2D bearer creation response message to the gateway.

Method of providing service continuity between cellular communication and device to-device communication

Provided are a device-to-device (D2D) group communication method and a device using the same. The method includes transmitting a scheduling request for D2D group communication to a base station, receiving first radio resource information for a status report of D2D data to be transmitted from the base station, transmitting a D2D buffer status report to the base station through a first radio resource, receiving second radio resource information including D2D resource allocation information necessary for the D2D group communication from the base station, and transmitting control information for the D2D group communication including a D2D group identifier (ID) as a device ID and D2D user data to two or more communication partner devices belonging to the D2D group.

Device to-device group communication method and device using the same

Disclosed is a method of transmitting and receiving a small amount of uplink data. A method of transmitting uplink data includes detecting uplink data to be transmitted, determining whether or not uplink data transmission is necessary only once, transmitting a service request message including information instructing that a data radio bearer not be generated when it is determined that uplink data transmission is necessary only once, starting a radio resource control (RRC) connection setup process, and performing the uplink data transmission once using a signaling radio bearer without generating the data radio bearer with reference to the information instructing that the data radio bearer not be generated, during the RRC connection setup process, when it is determined that \ uplink data transmission is necessary only once.

Method of transmitting small amount of uplink data and method of receiving small amount of uplink data

Provided is a technology that enables a terminal to quickly perform an idle-to-active state shift and to quickly perform a handover using a carrier aggregation characteristic. The terminal may attempt a Radio Resource Control (RRC) connection establishment using a plurality of carrier components. When the RRC connection establishment using one of the carrier components succeeds, the terminal may transmit an RRC reconfiguration complete message to a base station.

Idle-to-active state shift apparatus in carrier aggregation environment

Enclosed are a mobile terminal and a method of performing handover. The mobile terminal is connected to a selected network among a plurality of networks sensed in accordance with the movement of the mobile terminal so that handover is performed between different networks and that a service used by the mobile terminal is continuously provided. Therefore, the convenience of a user is improved and network utility is improved.

Growing community of inventors

Seoul, South Korea

You Sun Hwang