Abstract: A method and apparatus for notifying status of an MN in a WLAN system using VLC are provided, in which an AP allocates a first predetermined number of time slots per frame as unallocated slots, for status notification of an initially accessing MN and allocates a second predetermined number of time slots per frame as reserved slots, for status notification of an initially accessing MN and uplink data transmission of an MN, and the MN transmits a visible light signal carrying status information about the MN in one of an unallocated slot and a reserved slot, if the MN initially accesses the AP.

Abstract: A lateral flow atomic layer deposition (ALD) apparatus has two gas inflow channels and two gas outflow channels that are connected to two gas outlets that are symmetrically formed based on a substrate in which a thin film is deposited, thereby differently guiding a flow direction of a gas flowing on the substrate. Therefore, uniformity of a deposited film is improved, compared with the conventional lateral flow ALD apparatus in which a supplied source gas and reaction gas constantly flow in only one direction on the substrate.

Abstract: A method of processing a digital broadcast signal includes Reed-Solomon (RS) encoding enhanced service data for each column of at least one RS frame payload and adding a Cyclic Redundancy Check (CRC) checksum byte at a right end of each row of the at least one RS frame payload to build at least one RS frame and forming data groups including the enhanced service data in the built RS frame and a plurality of known data sequences. Forming the data groups includes mapping the RS encoded enhanced service data into each of the data groups and inserting a place holder for a non-systematic RS parity into each of the data groups. The method further includes deinterleaving data in each of the data groups including the enhanced service data and the place holder and multiplexing the enhanced service data in each of the formed data groups with main service data.

Abstract: A thin film deposition apparatus and a method of maintaining the same are disclosed. In one embodiment, a thin film deposition apparatus includes: a chamber including a removable chamber cover; one or more reactors housed in the chamber; a chamber cover lifting device connected to the chamber cover. The chamber cover lifting device is configured to move the chamber cover vertically between a lower position and an upper position. The apparatus further includes a level sensing device configured to detect whether the chamber cover is level, and a level maintaining device configured to adjust the chamber cover if the chamber cover is not level. This configuration maintains the chamber cover to be level as a condition for further vertical movement of the chamber cover.

Abstract: A digital television (DTV) transmitter and a method of processing known data in the DTV transmitter are disclosed. The method of processing known data in a digital television (DTV) transmitter includes generating a known data sequence, trellis-encoding the known data sequence, the trellis-encoded known data sequence having upper, middle, and lower bits, wherein at least one of the upper, middle, and lower bits has an m-sequence property, and mapping the trellis-encoded known data sequence into one of 2-level, 4-level, and 8-level data sequences, wherein the mapped data sequence has substantially an m-sequence property, wherein a data sequence has an m-sequence property when a peak value among auto-correlation values of the data sequence having a length of N is 1 and all the off-peak auto-correlation values are ?1/N.

Abstract: A method of processing a digital broadcast signal includes Reed-Solomon (RS) encoding enhanced service data for each column of at least one RS frame payload and adding a Cyclic Redundancy Check (CRC) checksum byte at a right end of each row of the at least one RS frame payload to build at least one RS frame and forming data groups including the enhanced service data in the built RS frame and a plurality of known data sequences. Forming the data groups includes mapping the RS encoded enhanced service data into each of the data groups and inserting a place holder for a non-systematic RS parity into each of the data groups. The method further includes deinterleaving data in each of the data groups including the enhanced service data and the place holder and multiplexing the enhanced service data in each of the formed data groups with main service data.

Abstract: A DTV transmitter includes a pre-processor pre-processing enhanced data, a data formatter generating enhanced data packets including the pre-processed data and inserting known data place holders to the data packets, and a multiplexer multiplexing the enhanced data packets with main data packets. It further includes an RS encoder which RS-codes the multiplexed data packets, and a data interleaves which interleaves the RS-coded data packets. The RS encoder adds systematic RS parity data to each main data packet and adds non-systematic RS parity place holders to each enhanced data packet. The RS encoder adds the RS parity place holders such that the RS parity place holders are placed after the enhanced data within each interleaved enhanced data packet.

Abstract: A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Abstract: A DTV receiver includes a tuner, a demodulator, a known sequence detector, and a frequency domain equalizer. The tuner initially receives a broadcast signal including valid data in which a known data sequence is periodically repeated. The demodulator demodulates the broadcast signal, and the known sequence detector detects the known data sequence from the demodulated signal. The frequency domain equalizer compensates channel distortion of the demodulated broadcast signal in a frequency domain using the detected known data sequence. In addition, the DTV receiver may further include a time domain equalizer which compensates channel distortion of the time domain signal, or a noise canceller which removes a predicted noise from the time domain signal.

Abstract: A DTV transmitter includes a pre-processor expanding original enhanced data, a data formatter generating enhanced data packets including the expanded enhanced data and inserting known data place holders into the data packets, a multiplexer multiplexing the enhanced data packets with main data packets including main data, and an RS encoder adding systematic RS parity data to each main data packet and adding non-systematic RS parity data holders to each enhanced data packet. It further includes a data interleaver interleaving the RS-coded data packets, a known data generator generating know data symbols, a converter converting the interleaved data packet into symbols, and a symbol processor processing the converted symbols. The symbol processor removes symbols representing the null data, encodes symbols representing the original enhanced data at a rate of N/M, and replaces symbols representing the know data place holders with known data symbols.

Abstract: A DTV receiver includes a tuner tuning to a channel to receive a broadcast signal, and a demodulator demodulating the broadcast signal. The receiver further includes a first decoder which decodes main and enhanced data included in the demodulated signal by calculating soft decision values for the enhanced data and hard decision values for the main data. The receiver further includes a second decoder for decoding the main and enhanced data for first forward error correction, and a third decoder for decoding the FEC-decoded enhanced data for second forward error correction.

Abstract: A method for retransmitting data when data transmission/reception has failed in a wireless LAN system using visible light communication. A mobile node searches a received frame for a fast feedback slot allocated for retransmission information when momentary data transmission/reception failure has occurred. One mini-slot from among the plurality of mini-slots is selected from the fast feedback slot. The mobile node transmits a fast feedback message, including information for retransmission, to an access point by using the selected mini-slot.

Abstract: A digital television (DTV) transmitter and a method of processing known data in the DTV transmitter are disclosed. The method of processing known data in a digital television (DTV) transmitter includes generating a known data sequence, trellis-encoding the known data sequence, the trellis-encoded known data sequence having upper, middle, and lower bits, wherein at least one of the upper, middle, and lower bits has an m-sequence property, and mapping the trellis-encoded known data sequence into one of 2-level, 4-level, and 8-level data sequences, wherein the mapped data sequence has substantially an m-sequence property, wherein a data sequence has an m-sequence property when a peak value among auto-correlation values of the data sequence having a length of N is 1 and all the off-peak auto-correlation values are ?1/N.

Abstract: A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Abstract: A DTV transmitter includes a pre-processor pre-processing enhanced data, a data formatter generating enhanced data packets including the pre-processed data and inserting known data place holders to the data packets, and a multiplexer multiplexing the enhanced data packets with main data packets. It further includes an RS encoder which RS-codes the multiplexed data packets, and a data interleaves which interleaves the RS-coded data packets. The RS encoder adds systematic RS parity data to each main data packet and adds non-systematic RS parity place holders to each enhanced data packet. The RS encoder adds the RS parity place holders such that the RS parity place holders are placed after the enhanced data within each interleaved enhanced data packet.

Abstract: A DTV receiver includes a tuner, a demodulator, a known sequence detector, and a frequency domain equalizer. The tuner initially receives a broadcast signal including valid data in which a known data sequence is periodically repeated. The demodulator demodulates the broadcast signal, and the known sequence detector detects the known data sequence from the demodulated signal. The frequency domain equalizer compensates channel distortion of the demodulated broadcast signal in a frequency domain using the detected known data sequence. In addition, the DTV receiver may further include a time domain equalizer which compensates channel distortion of the time domain signal, or a noise canceller which removes a predicted noise from the time domain signal.

Abstract: A digital television (DTV) transmitter and a method of processing known data in the DTV transmitter are disclosed. The method of processing known data in a digital television (DTV) transmitter includes generating a known data sequence, trellis-encoding the known data sequence, the trellis-encoded known data sequence having upper, middle, and lower bits, wherein at least one of the upper, middle, and lower bits has an m-sequence property, and mapping the trellis-encoded known data sequence into one of 2-level, 4-level, and 8-level data sequences, wherein the mapped data sequence has substantially an m-sequence property, wherein a data sequence has an m-sequence property when a peak value among auto-correlation values of the data sequence having a length of N is 1 and all the off-peak auto-correlation values are ?1/N.

Abstract: A DTV transmitter includes a pre-processor pre-processing enhanced data, a data formatter generating enhanced data packets including the pre-processed data and inserting known data place holders to the data packets, and a multiplexer multiplexing the enhanced data packets with main data packets. It further includes an RS encoder which RS-codes the multiplexed data packets, and a data interleaver which interleaves the RS-coded data packets. The RS encoder adds systematic RS parity data to each main data packet and adds non-systematic RS parity place holders to each enhanced data packet. The RS encoder adds the RS parity place holders such that the RS parity place holders are placed after the enhanced data within each interleaved enhanced data packet.

Abstract: A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

Abstract: A DTV receiver includes a tuner, a demodulator, a known sequence detector, and a frequency domain equalizer. The tuner initially receives a broadcast signal including valid data in which a known data sequence is periodically repeated. The demodulator demodulates the broadcast signal, and the known sequence detector detects the known data sequence from the demodulated signal. The frequency domain equalizer compensates channel distortion of the demodulated broadcast signal in a frequency domain using the detected known data sequence. In addition, the DTV receiver may further include a time domain equalizer which compensates channel distortion of the time domain signal, or a noise canceller which removes a predicted noise from the time domain signal.