Abstract: Provided is a failure recovery method in a non-revertive mode of an Ethernet ring network. In an Ethernet ring network, link priorities between nodes or node priorities are determined based on media access control (MAC) addresses and the nodes having blocked ports are determined after failures are recovered from based on the priorities so that the blocked ports can be distributed.

Abstract: Disclosed herein are a method of performing synchronization in a distributed wireless communication system, and a terminal supporting the same. A distributed wireless communication system includes a plurality of networks. Time resources of each of a plurality of networks are divided into a synchronization slot, a discovery slot, a peering slot, and a data slot. A first terminal belonging to a first network determines whether a synchronization signal is received from a terminal belonging to a second network in the data slot of the first network. The first terminal detects whether it has met the second network that is out of synchronization with the first network if the synchronization signal is determined to have been received.

Abstract: 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.

Abstract: 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.

Abstract: Provided is a failure recovery method in a non-revertive mode of an Ethernet ring network. In an Ethernet ring network, link priorities between nodes or node priorities are determined based on media access control (MAC) addresses and the nodes having blocked ports are determined after failures are recovered from based on the priorities so that the blocked ports can be distributed.

Abstract: Provided is a failure recovery method in a non-revertive mode of an Ethernet ring network. In an Ethernet ring network, link priorities between nodes or node priorities are determined based on media access control (MAC) addresses and the nodes having blocked ports are determined after failures are recovered from based on the priorities so that the blocked ports can be distributed.

Abstract: 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.

Abstract: 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.

Abstract: A method and apparatus for processing a timestamp using signature information on a physical layer is provided. The timestamp processing terminal uses a pseudo-random binary sequence to assign signature information to a message which is to be sent to another terminal, and verifies the signature information on a physical layer. The signature information is used to identify the message as a sync message. Accordingly, it is possible to precisely process the timestamp.

Abstract: 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.

Abstract: 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.

Abstract: The present invention, in preferred aspects, provides a communication method using a network coding packet in a wireless network, with reduced occurrence of negative acknowledgements, between a access point and plural mobile terminals.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method for enhancing transmission efficiency of burst data by estimating a void between burst data and filling the void with new burst data in an optical burst switching (OBS) network. To this end, a node in the OBS network receives burst data (BD) aggregated from data packets, and a burst control packet (BCP) that is received prior to the BD by an offset time. The BCP contains information relating to the offset time and the BD. To predict the void between the BDs, a void filling time is defined within the offset time using the BCP. The present invention provides the method for determining whether to fill the void and filling the void by directly monitoring the BD over a preset time.

Abstract: 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.