Electronics and Telecommunications Research Institute

Sung-Min Oh

Ae-Soon Park

Changhee Lee

JaeSheung Shin

Jae Heung Kim

Wooram Shin

Jung-Im Kim

Hyun Seo Park

Pyeong Jung Song

Ok-Sun Park

Hyun-Seo Park

Hyun-Yong Hwang

Sook-Yang Kang

Eunah Kim

Jeong Hwan Lee

Taesoo Kwon

Sook Yang Kang

A base station infers a random access failure rate depending on a random access collision of terminals performing random access and controls a random access opportunity of a terminal that fails the random access by using the random access failure rate of each terminal. Also, information for the controlled random access opportunity is transmitted to the terminal that fails the random access.

Method and apparatus for controlling random access opportunity in mobile communication system

A method for synchronization by a D2D terminal in a D2D communication network through receiving a first D2D synchronization signal from at least one D2D synchronization source and performing synchronization according to a synchronization timing reference provided through the first D2D synchronization signal, and a method for negotiating whether to perform a role as a synchronization source with another D2D synchronization source through determining, when a D2D synchronization signal and a D2D synchronization channel are received from at least one D2D synchronization source, whether to maintain a role as the independent synchronization source based on negotiation information for negotiation between synchronization sources included in the D2D synchronization channel, and operating as a relaying synchronization source when the role as the independent synchronization source is not maintained, are provided.

Method and apparatus for synchronization in D2D communication network

A method and apparatus for handover is provided. In a network environment in which a plurality of beams are provided within a base station, a terminal measures signal strength of a serving beam and signal strength of a target beam and transmits a measurement report message when a first condition or a second condition is satisfied. The base station determines inter-beam coordinated scheduling when the signal strength of the serving beam and target beam satisfy the first condition, and determines handover between beams when the signal strength of the serving beam and target beam satisfy the second condition. The base station transmits a message for commanding handover to the terminal when the handover between beams is determined. The terminal then stops communicating with the serving beam and performs handover to the target beam.

Method and apparatus for handover

A UE does not immediately perform handover after receiving a handover command from a serving base station, but instead backups that message and continuously compares the signal strength of a serving base station and the signal strength of a target base station and performs a handover to the target base station at the best timing when handover is required. Once the timing of handover is determined, the UE transmits a handover indication message to the serving base station, and thereafter the UE performs a handover to the target base station.

Handover method and apparatus

Growing community of inventors

Daejeon, South Korea

Sung-Min Oh