Gwangju Institute of Science and Technology

Electronics and Telecommunications Research Institute

Hyuk Lim

Wooyeol Choi

Jae-Hyung Jang

Hyunduk Kang

Yung-Kwan Kim

Jargalsaikhan Narantuya

Jaeseon Hwang

Cheol Sig Pyo

Jong Suk Chae

Chang Sub Shin

Bong Soo Kim

Heon Jin Hong

Jae Hyung Jang

Heon-Jin Hong

Jong-Won Kim

Tae-Jin Ha

Daewon Jung

Kwanhee Jeong

Chi-Wook Jeong

In Hyeok Jang

Hyo Joo Kim

Gyung Min Kim

Ryangsoo Kim

Sung Hwan Kim

Seung Hyun Yoon

In Shick Kim

Yong Gang Kim

A cloud-based Wi-Fi network architecture consisting of a CU and RAUs is proposed as an improvement on the conventional Wi-Fi architecture with traditional access points (APs). In addition, a method for uplink data transmission in a cloud-based Wi-Fi network is proposed. In a conventional Wi-Fi network with independently operating APs, APs close to each other may not be able to utilize the same frequency band efficiently because of significant amounts of interference. However, in a cloud-based Wi-Fi network, the CU coordinates RAUs so that they can operate in the same frequency band by transmitting or receiving signals through the shared wireless medium to improve spectral efficiency. For each frequency band, the proposed system utilizes a diversity combining that combines multiple signals and introduces a single improved signal with high signal-to-noise ratio for uplink transmission in the cloud-based Wi-Fi network. In proposed uplink transmission method for a cloud-based Wi-Fi network, diversity combining is utilized with the immediate acknowledgement (ACK) transmission method that transmits the ACK frame to the client immediately before decoding. The proposed uplink data transmission method mitigates the performance degradation caused by the fronthaul propagation delay between the CU and RAUs, without significant modification of the IEEE 802.11 standard.

Cloud-based Wi-Fi network system using immediate ACK in uplink data transmission

An apparatus for deploying a firewall on a software-defined network (SDN) includes a public key distributor configured to transmit a public key, a resource monitor configured to monitor resources of a network, a host monitor configured to receive a firewall rule of at least one host, which is encrypted by the public key, a decryption unit configured to decrypt information received from the host monitor by using a secret key, a merge unit configured to merge the decrypted information to provide a merged firewall rule, and a firewall deployment unit configured to deploy the merged firewall rule to a switch.

Apparatus and method for deploying firewall on SDN and network using the same

A full-duplex communication method for a multi-hop wireless network including a source end for transmitting data, a destination end as a destination of the data and at least one relay for connecting the source end and the destination end wirelessly includes sending a transmission request from the source end to the destination end through the at least one relay in forward order, sending a transmission confirmation from the destination end to the source end through the at least one relay in reverse order in response to the transmission request and the at least one relay entering a ready state, and transmitting the data from the source end to the destination end through the at least one relay using a full-duplex scheme after receiving the transmission confirmation.

Full-duplex communication method for multi-hop wireless network

The present invention includes: defining a transmission signal generated by the AP and a transmitter (TX) configured to transmit a signal to the AP and reception signals generated by the AP and receivers (RXs) configured to receive a signal from the AP, and canceling self-interference in consideration of a channel gain of the self-interference at the AP; defining a channel transmitted from the TX to the AP as uplink, defining a channel transmitted from the AP to the RX as downlink, and deriving a signal-to-interference-plus-noise ratio (SINR) for a signal transmittable on the uplink and the downlink; selecting an RX capable of maximizing a capacity sum of transmit powers of the AP and the TX; and selecting optimum transmit powers of the AP and the TX for maximizing SINRs of transmission on the uplink and the downlink.

Method for controlling medium access in full-duplex Wi-Fi network

A method for detecting an intrusion in a network is disclosed. The network includes a plurality of nodes for data transmission/reception and switches for relaying flow transmission/reception between the nodes, and an intrusion detection system (IDS) is combined with the network to form a system The method includes: installing SDN-enabled switches for flow sampling in the network to connect them to SDN controllers; determining, by the SDN controller, the number of network flows and the number of switches; deriving a sampling rate for each of the SDN-enabled switches; forwarding, by the switches, packet information sampled at respective sampling rates to the IDS; and identifying, by the IDS, malicious data based on the packet information to update the sampling rate of each of the SDN switches.

Method for detecting intrusion in network

Disclosed is a wireless communication system including: an access point; and at least two wireless devices capable of transmitting packets to the access point at the same time, wherein the access point receives a packet from at least one of the at least two wireless devices within multi-packet reception (MPR) capability after determining whether packet reception is beyond the multi-packet reception (MPR) capability, when receiving a request to send (RTS) from one of the at least two wireless devices. Thus, it is possible to obtain maximum throughput by optimally using the MPR capability and stably perform packet communication even though the number of wireless devices changes or the wireless device is moved.

Wireless communication system and packet communication therefor

Disclosed is a data dissemination system for vehicles. The data dissemination system includes a vehicle, a vehicle cloud system, and access points connecting with and transferring data to the vehicle and the vehicle cloud system and being stationary near a road, wherein the vehicle comprises a navigator for determining location information, the vehicle cloud system comprises a dissemination setting unit for determining which data to disseminate to which access point based on the location information and vehicle route information, and the data disseminated to the access point is disseminated to the vehicle. According to the present invention, data transfer between vehicles and an infrastructure can be easily achieved such that a large amount of data can be exchanged therebetween, data transfer efficiency can be enhanced, and network resources can be fully utilized. Accordingly, the present invention has advantages of contributing to dissemination and utilization of the vehicle cloud system.

Vehicle, vehicle cloud system, and data dissemination system

Disclosed herein is a medium access control method in a single channel wireless network environment, which is a medium access control method of a receiving side terminal capable of communicating in a full-duplex communication scheme. The medium access control method includes: receiving a frame header of a data frame; and transmitting an ACK frame in response to the frame header.

Medium access control method in single channel wireless network environment

In a medium access control method of an access point for a wireless LAN, the access point is capable of full-duplex communication, and the medium access control method includes receiving a frame header of a first data frame from a first terminal, and transmitting a second data frame to a second terminal while the first data frame is received from the first terminal.

Access point for wireless LAN and medium access control method thereof

Provided are a packet transmission scheduling method in a wireless network and a packet transmission method using the same. The packet transmission scheduling method, includes storing location information and a path loss exponent of each node on a multiplexing path; calculating a Signal-to-Interference and Noise Ratio (SINR) between nodes on a predetermined path based on the stored location information; when the calculated SINR exceeds a threshold, forming the paths as a path table; and scheduling packet transmission based on the formed path table.

Packet transmission scheduling method for simultaneous packet transmission in multiplexing paths in wireless network, and packet transmission method using the same

A method of recognizing a tag in an RFID reader includes: obtaining a predetermined frame size in the case where throughput obtained by reflecting a slot length based on the remaining number of tags except for recognized tags within a frame progressing current tag recognition that substantially has a maximum value; and when the current frame size is different from the predetermined frame size, stopping the current progress of frame and changing the current frame size into the expected frame size. The method of recognizing a tag may further include when the current frame size is equal to the expected frame size, changing the current frame size into the frame size that does not cause a throughput inversion phenomenon for the remaining number of tags to be recognized within the frame progressing the current tag recognition. By the throughput inversion phenomenon, the occurrence of throughput loss can be prevented and the tag recognition time is reduced to recognize the tags at high speed.

Method of recognizing RFID tag for the purpose of preventing throughput inversion and RFID reader performing the same

Provided are a method of adjusting a PCS threshold in a wireless network, and a terminal apparatus for the wireless network. The method and the apparatus determines whether to adjust the PCS threshold to use a shared channel for transmitting data in a wireless network based on a congestion status of the shared channel, and adjusts the PCS threshold based on a packet loss measured for a predetermined period of time.

Method of adjusting PCS threshold and terminal apparatus for high density wireless network

Provided is a cross-layer routing method in a wireless sensor network including: locating a destination node which is a final destination of data by a source node which generates the data; and determining an optimal relay node among one or more neighboring nodes using their position information for each hop and forwarding the data from the source node to the destination node through the determined relay nodes. Therefore, an effective and stable routing which reduces overheads of additional control messages used for stable data forwarding and reduces collisions in a shared channel by using wireless link layer characteristics can be implemented.

Cross-layer routing method in wireless sensor network

A security system using a laser range finder that can precisely determine an existence and a location of an intruder, and a method of detecting the intruder using the laser range finder are provided. The security system using a laser range finder, the security system includes: the laser range finder emitting laser beam, receiving the reflected laser beam, measuring a distance between the laser range finder and a target object, and detecting an existence and a location of an intruder; and at least one reflective means reflecting the emitted laser beam toward the laser beam finder, wherein at least one reflective means is spaced by a predetermined distance of the laser range finder and is installed a predetermined distance from the laser range finder.

Security system using laser range finder and method of detecting intruder using laser range finder

Disclosed is a navigation apparatus and method using RFID that is capable of providing information on a current position and a moving direction to the destination. An antenna unit has directivity in a predetermined direction and receives at least one radio signal transmitted from at least one RFID tag. An RFID reader converts the at least one radio signal provided by the antenna unit into information on the at least one RFID tag in a digital form, measures the reception strength of the at least one radio signal, and provides the information on the at least one RFID tag and information on the received strength. A control unit determines the current position and moving direction on the basis of the information on the at least one RFID tag and the information on the reception strength provided from the RFID reader. Accordingly, it is possible to accurately recognize the current position and the moving direction of the navigation apparatus and guide the moving direction to the destination.

Growing community of inventors

Gwangju, South Korea

Hyuk Lim