Korea Advanced Institute of Science and Technology

Icu Research Industrial Cooperation Group

Samsung Electronics Co., Ltd.

Electronics and Telecommunications Research Institute

June Koo Rhee

Kyu Sang Lee

Kyong Chun Lim

Dujeong Lee

Chan T D Thai

Jihoon Sung

Jin Hyeock Choi

Sangwoo Lee

Jong Ho Bang

Hyun Seo Oh

Ji Hwan Kim

Byung Chang Kang

Byung Moo Lee

Min Ho Kang

Junhyuk Kim

Chan Kyun Lee

Kyounghye Kim

Jun Hyuk Kim

YongHwan Bang

Jung Yul Choi

Doojung Lee

Yong Seen Kim

Jun Sang Oh

Chang Ho Suh

Chan-Kyun Lee

Ii Hwan Park

Sangsu Jung

The present invention, which is used for continuous variable quantum key distribution (CVQKD) with asynchronous local oscillators, relates to a system for performing a phase compensation of a scheme of using LO phase estimation and feedback at a receiver (Bob) using a pilot signal from a transmitter (Alice) and a scheme of measuring quantum state data using an LO having a predetermined phase at the receiver (Bob) and estimating and feeding back an LO phase through multi-dimensional reconciliation (MDR).

Continuous variable quantum key distribution phase compensation system

The present invention relates to a method and an apparatus for quantum key distribution according to a continuous-variable quantum key distribution protocol, which distributes the quantum key in a reverse post-processing manner and, after photon sub traction at a receiver (Bob), detects bit information from a received quantum state to calculate and share the quantum key, such that security can be further enhanced and a cryptographic key generation rate can be increased since the cryptographic key is not exposed to an attacker (Eve).

Method and apparatus for quantum key distribution on basis of photon subtraction from receiver

A communication device, a multicast control method, and a scheduling control method are disclosed. The communication device includes: a decoding buffer that stores a first multicast packet received from a first node and a second multicast packet received from a second node; an encoder that performs network coding of the first and second multicast packets; and a transmitter that transmits the network-coded packets output from the encoder to the first node and the second node.

Communication device, multicast control method, and scheduling control method

Disclosed are a forward discrete/inverse-discrete Fourier transform device and method for optical orthogonal frequency division multiplexing (OFDM) communication and a transmitting and receiving apparatus. The forward inverse-discrete Fourier transform device includes N 1:N splitters for splitting subcarrier signals received from N inputs corresponding to the number of optical frequencies of subcarriers, a phase shift delay array module for shifting phases of the split signals from the 1:N splitters, N N:1 power couplers for coupling signals output from the phase shift delay array module, a time delay array module for performing time delay on optical OFDM symbols from the N:1 power couplers, and an N:1 power coupler for coupling signals output from the time delay array module.

Forward discrete/inverse-discrete Fourier transform device and method for optical OFDM communication and transmitting and receiving apparatus comprising the device

A method and apparatus for user scheduling in a multi-user multiple input multiple output (MIMO) communication system are provided. The method includes identifying a user group comprising user terminals. The method further includes comparing power consumptions based on the user group. The method further includes scheduling the user terminals based on the comparing.

Method and apparatus for user scheduling in multi-user multiple input multiple output (MIMO) communication system

A packet switching system includes a plurality of switch fabrics connected in cascade and a plurality of buffers respectively connected to the plurality of switch fabrics. In the event of packet competition, the plurality of switch fabrics buffer the competing packets to the corresponding buffers through buffer connection ports, and forward the competing packets in excess of the number of buffer connection ports to an adjacent switch fabric through switch connection ports.

Packet switching system and method

A wireless mesh network system generates at least one virtual node within a transmission area of a specific mesh node when no mesh nodes exist in two or three continuous quadrants within the transmission area with reference to the specific mesh node. Also, the system performs routing by combining uplink and downlink routing methods so as to support unicast between the mesh nodes in a domain. Further, a channel access order of the mesh nodes is determined based on the potential values allocated to the mesh nodes forming the wireless mesh network according to the field theory. In this instance, the channel access order can be established by a central control method by a central processor for controlling the wireless mesh network or a distributed control method using contention per mesh node.

Wireless mesh network system, virtual node generating method, thereof, unicast packet routing method, and scheduling method thereof

The present invention provides a method and apparatus for multicast transmission of a transmitting station in a wireless network. The method according to the present invention transmits a plurality of data packets to a plurality of receiving stations, receives information on loss of the plurality of the data packets from at least one of the plurality of the receiving stations, codes the plurality of the data packets into a single coded data packet based on the information on the loss of the plurality of the data packets and transmits an error control frame including the coded data packet to the plurality of the receiving stations. Therefore, when an error occurs at a data packet that a transmitting station transmits to a plurality of receiving stations by a multicast transmission, a number of retransmission of the data packet can be reduced.

Method and apparatus for multicast transmission in wireless network

Benes networks include an input stage having a plurality of input ports, an input connection stage configured to connect output signals of the input stage, an add connection stage configured to connect outputs of the input connection stage and to connect inputs of add ports corresponding in number to the number of the plurality of input ports, a drop connection stage configured to connect outputs of the add connection stage, to output some outputs to a next stage, and to output some outputs to drop ports, an output connection stage configured to connect the some outputs of the drop connection stage to an output side, and an output stage configured to output the outputs of the output connection stage to output ports.

Add-drop benes networks

Provided is an apparatus for transferring optical data in an optical switching system using time synchronization. The apparatus performs time synchronization on optical data to input the optical data at regular intervals through fiber delay line for time synchronization respectively disposed on input ports. Therefore, the apparatus can efficiently reduce a data blocking rate in comparison with a conventional optical switching system using an asynchronous electric buffer without a synchronous process, and achieve the same performance as conventional asynchronous technology despite using fewer wavelength converters and buffers, thus reducing system cost. In addition, using dynamic time synchronization modules, the apparatus performs time synchronization for minute time variation due to an environment such as temperature.

Apparatus for transferring optical data in optical switching system using time synchronization

Growing community of inventors

Daejeon, South Korea

June Koo Rhee