Abstract: Disclosed is a method for transmitting asynchronous data in a synchronous Ethernet having a sync frame section and an async frame section. The method includes the steps of: a) allocating a priority to motion picture data for transmission through the sync frame section; b) determining if a size of the data of all frames for transmission in one cycle exceeds the predetermined length; c) dropping motion picture data having a lower priority (e.g. which corresponds to the size of the data exceeding the predetermined length); and d) transmitting the data in one cycle unit when the size of the data to be transmitted does not exceed the predetermined length.

Abstract: Disclosed is a broadcast splitter enabling a selective transmission in real time. The broadcast splitter divides one multi-program transport stream (MPTS), which is obtained by multiplexing motion picture expert group-2 transport streams (MPEG-2TSs), into several single program transport streams (SPTSs). In particular, the broadcast splitter for MPEG-2TSs has a function of selecting a desired SPTS by performing a switching operation with respect to an MPTS in real-time without storing the MPTS when the MPTS is split into several SPTSs. Accordingly, it is possible to transmit MPTS signals in real time because desired TSs are extracted and delivered to output ports in real time by using a broadcast switch without storing the MPTS signals in a storage unit such as a RAM.

Abstract: An apparatus for IP streaming capable of smoothing a multimedia stream is disclosed. The apparatus transmits real-time broadcast through an Internet protocol (IP) network and reduces transmission loss by lowering the influence derived from jitters in an IP network having a burst characteristic. The apparatus is capable of smoothing a multimedia stream in a multimedia stream service outputting data through buffering based on a packetized elementary stream packet unit, which is easy to synchronize voice with video and suitable for the real-time multimedia stream service.

Abstract: A hybrid passive optical network (PON) includes a central office (CO) for multiplexing at least one downstream optical signal for broadcasting and a plurality of downstream optical signals for communication. The PON further includes a remote node (RN) connected to the CO using at least one feeder fiber (FF), and a plurality of optical network units (ONUs), each connected to the RN using at least one distribution fiber (DF). The RN demultiplexes the multiplexed downstream optical signal received from the CO into the downstream optical signal for broadcasting and the downstream optical signals for communication, and multi-splits the downstream optical signal for broadcasting. The RN transmits each split broadcasting downstream optical signal and its corresponding downstream optical signal for communication to each ONU.

Abstract: A multimedia signal matching system for performing a picture-in-picture function includes: at least one set-top box including a decoder for decoding multimedia signals in a predetermined reference format and generating a control signal for performing the picture-in-picture function; and a multimedia matching device for receiving multimedia signals in various formats from a broadcast communication network and the control signal from the set-top box, processing the received multimedia signals into signals with the predetermined reference format responsive to the control signal.

Abstract: Disclosed is a wavelength-division multiplexing-passive optical network having a central office including a plurality of first working and protection transmit/receive modules, working and protection optical transmitters, and a plurality of first optical switches, the first working and protection transmit/receive modules generating downstream optical signals and detecting upstream optical signals having corresponding wavelengths, the working and protection optical transmitters generating broadcasting optical signals, the first optical switches performing a switching operation when faults occur, a plurality of subscriber units for receiving broadcasting optical signals and downstream optical signals having corresponding wavelengths and generating upstream optical signals, the subscriber units including second optical switches, a remote node including working and protection optical splitters for dividing intensity of the broadcasting optical signals, the remote node being positioned between the subscriber units

Abstract: Disclosed are an optical transceiver and an passive optical network using the same. The optical transceiver includes a polarization splitter for splitting injected light input from an outside of the optical transceiver into a first polarization component and a second polarization component, a light injected transmitter for receiving the first polarization component and outputting an optical signal generated based on the first polarization component, and an optical receiver for detecting an electrical signal based on the second polarization component.

Abstract: A wavelength division multiplexing passive optical network including optical lines for link is disclosed. The passive optical network includes a plurality of optical network units each of which generates an upstream optical signal; a central office for generating downstream optical signals to be provided to each of the optical network units, and differentially converting each of the upstream optical signals into a monitoring signal and a received signal. Changes in the wavelength of each of the upstream optical signals are monitored and if there is an abnormality in each optical line by using relevant monitoring signals. The network also includes a remote node for multiplexing and outputting the upstream optical signals to the central office, and demultiplexing and outputting the downstream optical signals to corresponding optical network units.

Abstract: An access point (AP) for ensuring a Quality of Service (QoS) of a broadcasting service in a Wireless Local Area Network (WLAN) is provided. A broadcast signal input unit receives a broadcast signal and depacketizes the received broadcast signal into a transport stream. A broadcast signal control unit receives channel selection information of a terminal, creates a zapping signal (protocol) and a control signal using bandwidth information to control a broadcast signal. A broadcast signal switching unit selectively receives the transport stream using the zapping signal, stores the received transport stream for a predetermined amount of time, and outputs the stored transport stream to the broadcast signal control unit through time slicing using the control signal.

Abstract: A media server coupled to a service network by means of a media gateway provides network-adaptive media streams through hybrid monitoring for the digital home service. Clients coupled to the service network measures a network state of the service network and system states of the clients through the hybrid monitoring. A monitoring server includes a domain manager and receives metric information fed back from the clients, performs comparison and analysis with respect to the received measurement information, determines causes of quality degradation of the digital home service, and delivers indication information according to the causes to the media server and the media gateway. The domain manager also determines a problem of the media streams according to a predetermined policy and an analysis result of the condition-analyzing unit and for createing the indication information in order to solve the problem.

Abstract: Disclosed are an optical transceiver and an passive optical network using the same. The optical transceiver includes a polarization splitter for splitting injected light input from an outside of the optical transceiver into a first polarization component and a second polarization component, a light injected transmitter for receiving the first polarization component and outputting an optical signal generated based on the first polarization component, and an optical receiver for detecting an electrical signal based on the second polarization component.

Abstract: In a digital broadcasting system comprising a server for retransmitting a digital broadcast on the basis of an Internet protocol (IP), a user terminal for receiving the digital broadcast on the basis of the IP, and a router for connecting the server with the user terminal, the server performs a method for providing the broadcasting channel information that includes the steps of dividing a broadcasting stream to be transmitted to the user terminal into the broadcasting channel information and other information excluding the broadcasting channel information by demultiplexing the broadcasting stream and extracting the broadcasting channel information from the divided broadcasting stream, converting the extracted broadcasting channel information into IP-based broadcasting channel information by inserting the Internet protocol information for each broadcasting channel into the extracted broadcasting channel information, and remultiplexing the IP-based converted broadcasting channel information and the other inform

Abstract: A method and apparatus by which a reception device of a communication system can sense and compensate for an error of a program clock reference (PCR), and can sense and compensate for bit rate variation of transmission data in a transmitted MPEG-2 TS. The method and apparatus compensates for a PCR jitter, or a change in a data bit rate, which may occur in processing an MPEG-2 TS in a reception device of the MPEG-2 TS transmission system, thereby preventing the deterioration of image quality due to the jitter or loss of an input MPEG-2 TS data. The apparatus includes a PAT sensing unit for sensing a PAT from a received MPEG-2 TS, a PMT sensing unit for sensing a PMT based on information provided from the PAT sensing unit, a PCR PID unit for sensing a PCR PID based on information provided from the PMT sensing unit and a PCR data unit for outputting a PCR data based on information provided from the PMT sensing unit and PID information provided from the PCR PID unit.

Abstract: A method for transmitting video data to the users via a network in a transcoder of an image processing system including a storage media having a predetermined amount of storage area is disclosed. The method includes the steps of storing in the storage media, the video data provided based on the corresponding services, monitoring a traffic condition of the network to determine if transcoding is necessary; transmitting the stored video data to the corresponding users, respectively, via the network, when the transcoding is not necessary; and transcoding the stored video data to transmit the video data to the corresponding users, respectively, when the transcoding is necessary. The video data provided is based on the corresponding services includes image information having the highest quality of service from a content provider.

Abstract: A wavelength-division multiplexing passive optical network (WDM-PON) comprising a central office for generating monitor light and multiplexed downstream optical signals to be out and detecting upstream optical signals, the central office including a signal monitoring unit monitoring based on fed-back monitor light if the wavelengths of the upstream optical signals and the wavelengths of the downstream optical signals change, a plurality of subscriber units for detecting corresponding downstream optical signals and generating upstream optical signals, a remote node for reflecting the monitor light to the central office, de-multiplexing multiplexed downstream optical signals so as to output the downstream optical signals to the corresponding subscriber units, and multiplexing the upstream optical signals so as to output the upstream optical signals to the central office, a first optical path for linking the central office to the remote node, and a plurality of second optical paths for linking the remote node to

Abstract: Disclosed is a passive optical network comprising a central office including a plurality of first reflective semiconductor optical amplifiers of a quantum-dot type, each of which generates a wavelength-seeded downstream optical signal on a downstream channel of a corresponding wavelength, a plurality of optical network units each of which includes a second reflective semiconductor optical amplifier of a multi-quantum-well type, the second reflective semiconductor optical amplifier generating a wavelength-seeded upstream optical signal on an upstream channel of a corresponding wavelength and a remote node for outputting the downstream optical signals to corresponding optical network units, and multiplexing and outputting the upstream optical signals to the central office.

Abstract: An optical transmitter for generating return-to-zero alternative-mark-inversion (RZ-AMI) optical signals and a method for generating the optical signals are provided. The optical transmitter includes a light source radiating at its output an intensity-modulated light beam based upon intensity of a first data, a precoder for precoding a second data having the information identical to the first data, and a Mach Zehnder modulator for phase-modulating the intensity-modulated light on basis of the precoded second data to generate a return-to-zero alternative-mark-inversion (RZ-AMI) optical signal.

Abstract: An optical network for bi-directional communication includes: a base station for generating downlink optical signals and detecting uplink optical signals; and a remote antenna unit for transmitting the downlink optical signals and generating the uplink optical signals to the base station; wherein the remote antenna includes: an optical detector for converting the downlink optical signals into downlink radio signals; an antenna for transmitting the downlink radio signals to outside thereof, and receiving the uplink radio signals in wireless communication; a semiconductor optical amplifier for converting the uplink radio signals into the uplink optical signals to output the uplink optical signals to the base station; and a circulating device having a plurality of ports, each of which is connected to the antenna, the optical detector, and the semiconductor optical amplifier, respectively.

Abstract: A bi-directional metro-access optical network includes a central office for generating beams of different wavelength bands and a plurality of wavelength locked downward optical signals and for detecting wavelength locked upward optical signals; a plurality of nodes for detecting the downward optical signals of different wavelengths and for generating the wavelength locked upward optical signals of which wavelengths are locked by respective wavelength beams; a first optical fiber line for linking together each of the nodes with the central office in a ring shape, transmitting the upward optical signals to the central office, and transmitting the downward optical signals and the beams to each of the nodes; and a second optical fiber line for linking together each of the nodes with the central office in a ring shape along the circumference of the first optical fiber line.

Abstract: A method of enabling transmission of a time-critical control signal event in a sync frame period, such as a pause signal that is generated when the receive buffer of an Ethernet switch is filled with packets beyond a threshold due to congestion of uplink asynchronous data, is disclosed. To transmit time-critical information in a synchronous Ethernet system, a current transmission period is checked upon detection of a time-critical event. If the current transmission period is a sync frame period, time-critical control information is generated, inserted into the first sub-sync frame after the time-critical event, and transmitted. If the current transmission period is an async frame period, a control frame including the time-critical control information is generated and transmitted.