Electronics and Telecommunications Research Institute

Korea Advanced Institute of Science and Technology

Yonsei University

Hyun Seo Oh

Sangwoo Lee

Hyun Kyun Choi

Min Soo Kim

Mun Geon Kyeong

Woong Cho

Jong-Hyun Park

Hyeong Geun Park

Jong Min Park

Dong Yong Kwak

Kyeong-Soo Han

Han Byeog Cho

Jae Ho Jung

Minseok Kim

Hyun Suk Kim

Sung Won Sohn

Il-Soon Jang

Kyung Hi Chang

June Koo Rhee

Dong-Sun Lim

Jong-Moon Chung

Bub Joo Kang

Jae Ryong Shim

Sunghwan Moon

Deuk Su Lyu

Eung Bae Kim

Hyoung-Goo Jeon

Dujeong Lee

Cheon In Oh

YongHwan Bang

Hyeong Geon Park

Sangin Kim

Chae Min Park

Daeki Hong

Hyung Gun Park

In a wireless multi-hop network, a transmission scheduling apparatus calculates a transmission demand of every node within the wireless multi-hop network, and allocates a time slot to each node by using the transmission demand of each node.

Transmission scheduling apparatus and method in wireless multi-hop network

In a vehicle communication system, a frame transmitting apparatus gives a transmission opportunity to an emergency frame received from an upper layer without EDCA (Enhanced Distributed Channel Access), and gives a transmission opportunity to a generic frame received from an upper layer through EDCA.

Apparatus and method for transmitting frame in vehicle communication system based on wireless access for vehicular environment

In a vehicle communication system, a multi channel operation apparatus for communication of a vehicle or a road side base station operates a multi channel in one physical layer and differentially transmits a frame through a corresponding channel according to a user priority order value of a frame to transmit.

Apparatus and method for operating multi-channel based on wireless access in vehicular environments

When supporting the handover from first road side equipment of a plurality of sets of road side equipment and second road side equipment that is adjacent to the first road side equipment to a vehicle, the first road side equipment generates a first channel seizing signal that is longer than that of the second road side equipment in a control channel of an N-th sync interval. The second road side equipment generates a second channel seizing signal that is longer than that of the first road side equipment in a control channel of an (N+1)-th sync interval.

Method of generating signal for supporting vehicle communication handover

A safe driving providing system for supporting a safe driving of a vehicle includes: a radar for transmitting a signal of a predetermined frequency bandwidth to a plurality of vehicles, analyzing signals provided by the vehicles, calculating location information and distance information of the vehicles, and finding inter-vehicle distance information of the vehicles based on the location information and the distance information; and a controller for receiving operation speed information from a vehicle information terminal device installed in each vehicle, determining driving safety of the plurality of vehicles based on the received operation speed information and inter-vehicle distance information provided by the radar, and transmitting a warning message for safe driving to the vehicle information terminal device.

System and method for providing driving safety

In order for a source node including a vehicle multihop protocol unicast apparatus to route data to a destination node, the source node broadcasts a location request message to neighbor node and receives a location response message from the neighbor nodes in response to the location request message. Therefore, the source node routes unicast data on the basis of the location information of the destination node included in the location response message. At this time, the source node uses a location based forwarder selecting algorithm in order to select a forwarder.

Location based vehicle multihop protocol unicast apparatus and routing method using the apparatus

A first roadside equipment operates as a transmitting/receiving mode in a control channel interval of an Nth synchronization interval so as to support a handover. In this instance, a second roadside equipment neighboring to the first roadside equipment operates as a receiving mode in the control channel interval of the Nth synchronization interval. The first roadside equipment operates as the receiving mode in a control channel interval of an (N+1)th synchronization interval. In this instance, the second roadside equipment operates as the transmitting/receiving mode in the control channel interval of the (N+1)th synchronization interval.

Channel access method for vehicle communication handover

A device for allocating a channel by using wireless access in a vehicular environment in which an onboard unit is provided in a vehicle and at least one roadside unit is provided, receives a service announcement message from at least one roadside unit, uses the service announcement message to generate an available service table, determines whether the available service table has roadside unit entries for transmitting the service announcement message, and if so, compares average RSSI provided by the roadside units to select a roadside unit to access, selects a channel that corresponds to the service provider ID with the highest priority from among the service provided by the selected roadside unit, and assigns the selected channel as a service channel to exchange information with the roadside unit.

Channel allocation device and method using wireless access in vehicular environments

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

An apparatus for time synchronization of an orthogonal frequency division multiplexing (OFDM) system oversamples a received signal using a master clock having a frequency at least four times higher than a minimum sampling frequency in a transmission apparatus, sets one of a plurality of oversampled signals to an on-time signal, and shifts each of the remaining oversampled signals by a predetermined time on the basis of the on-time signal. The apparatus for time synchronization calculates a correlation value by correlating each of the shifted signals and the on-time signal with a previously known signal, detects a maximum energy value among the calculated correlation values, and detects a start point of a frame by comparing the maximum energy value with a predetermined threshold value.

Apparatus and method for time synchronization and reception apparatus of OFDM system

A cooperative communication method for vehicular communication is provided. The method in which when one vehicle transmits a signal to another vehicle, a signal of a transmission vehicle passes through a roadside device or a plurality of vehicles and thereafter signals having a plurality of paths are transmitted to a reception vehicle, and the reception vehicle combines and demodulates the signals received through the plurality of paths.

Cooperative communication method for vehicular communication

Disclosed are an apparatus for forward beamforming using a terminal feedback and a method thereof. The base station estimates an angle of arrival (AOA) range of a user signal from reverse link received data and calculates a plurality of beamforming weights steering the estimated AOA range. Then, the base station transmits a user pilot signal by sequentially using the plurality of beamforming weights at different time areas through a control channel to estimate a forward channel conditions. A terminal calculates the user pilot signal power for all fingers at the respective time areas and feeds a time area number corresponding to the greatest power back to the base station. The base station transmits a data channel signal using a beamforming weight corresponding to the time area number fed back from the terminal.

Apparatus for forward beamforming using feedback of multipath information and method thereof

This invention relates to a method and apparatus for increasing the performance of searcher by using the array antenna when the signal to interference plus noise ratio is low. The two-dimensional searcher performs the spatial-filtering to reduce the noise and interference components and then correlates the spatial-filtered signal with a pseudo noise (PN) code to thereby detect the incoming signals and acquire the corresponding code timings. Furthermore, the two-dimensional searcher can be used to increase the performance of a finger beamformer in two ways. One is to use searcher beamforming weight as initial finger beamforming weight to increase the convergence speed in the adaptive beamforming algorithms. The other is to reduce an amount of computation in the angle of arrival estimation algorithms by calculating the azimuth power spectrum only for the specific angle range.

Method and apparatus for searcher beamforming in CDMA base station system using array antenna

An apparatus and method for canceling pilot signals from neighbor base stations is disclosed. The present invention cancels unnecessary pilot signals transmitted from the neighbor base stations by detecting, analyzing a PN signal in a pilot signal of each base station, generating estimated interference signal according to analyzed information from the detected PN signal and subtracting estimated interference signal from the received signal. Therefore, the present invention increases a bandwidth of downlink transmission channel and improves the demodulator to be operatable in low signal-to-noise ratio (E /N ).

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Daejeon, South Korea

Hyun Seo Oh