Abstract: Provided is a method of dividing a payload intra-frame for improving throughput of a carrier sensing multiple access/collision avoidance (CSMA/CA) wireless communication network. The payload intra-frame dividing method includes a data frame dividing step and a physical layer frame generating step in which a physical layer receives a plurality of data frames from an upper layer within a range of the maximum data frame length the physical layer can transmit and transmits the data frames as a single physical layer data frame. Furthermore, an acknowledge (ACK) frame is provided, which can minimize the deterioration of throughput even when a data frame, which has been divided into a plurality of data frames and transmitted as a single data frame, is required to be re-transmitted because an error is generated in the data frame.

Abstract: An OFDM receiver for interlocking FFT window position recovery with sampling clock control, and a method thereof are provided. This method includes the steps of: extracting a pilot signal from fast-Fourier-transformed OFDM received signals, and detecting inter-pilot phase differences; averaging the detected phase differences for a symbol and normalizing the mean phase difference by dividing it into reference values corresponding to phase differences generated when FFT window errors of at least one sample exist; and simultaneously controlling the FFT window position offset using a value obtained by rounding off the normalized value, and the sampling clock offset using the difference between the round-off value and the normalized value.

Abstract: Orthogonal frequency division multiplexing (OFDM) transmitting and receiving apparatus and methods can extend a communication distance by duplicated transmission of symbols in multiple channels. An input OFDM data bitstream is encoded to generate a symbol stream. The symbol stream is copied into multiple symbol streams and converted into data complex symbol streams by a modulation method. An input pilot bitstream is converted into a pilot complex symbol stream, and the pilot complex symbol stream is inserted into the data complex symbol streams to generate transmission symbol streams. Fast Fourier transform (FFT) processing of the transmission symbol streams is performed. Guard intervals (GIs) are inserted into the FFT processed signals. The signals are converted into analog signals, loaded onto carriers and transmitted.

Abstract: There is provided a multi-carrier transmission system which includes: an encoder for converting a data sequence into encoded symbols corresponding to respective sub-carriers; a first shifter for rearranging the encoded symbols to define a guard interval length; an inverse fast Fourier transform (IFFT) unit for inverse fast Fourier transforming the rearranged encoded symbols; a second shifter for processing the transformed symbols to effect a frequency shift to compensate for a frequency shift effected by the IFFT unit; and a guard interval inserter for interleaving symbol replicas with the processed symbols according to the guard interval length. The data transmission system of the present invention performs sub-carrier relocation function and guard interval insertion function using relatively simple elements in order to reduce the data processing time. As a result, the transmission efficiency of the entire communication system is enhanced.

Abstract: A received signal is converted into a digital signal through an A/D converter and then converted into the polar coordinate system. A synchronizer removes a frequency offset from the digital signal. the digital signal is again converted into an orthogonal coordinate system and a fast fourier transform is performed with a FFT. The digital signal is again converted into the polar coordinate system. An equalizer and a phase compensator compensate respectively a channel distortion and a phase error to the digital signal. Thus, the OFDM receiver using polar coordinate system and method thereof of the present invention can reduce the number of adders and multipliers required in a frequency synchronization, a compensation for channel influence, and a removal of remaining phase error by processing the signal in the polar coordinate system, thereby simplifying the calculation process and the receiver.

Abstract: A timing and frequency offset estimation method for OFDM use an analytic tone in calculating timing offset estimation and a frequency offset estimation. An analytic tone includes a signal that contains only one subcarrier and has characteristics of a uniform magnitude and a uniform phase rotation. The estimation algorithm with an analytic tone is based correlation function. By changing the interval between two samples in correlation, the maximum estimation range for the frequency offset can be extended to ±N/2 subcarrier spacing, where N is the number of total subcarriers. Thus, the frequency synchronization scheme for OFDM systems has a wider range and a more simple complexity than traditional ones requiring separate fine and coarse synchronization.

Abstract: An OFDM receiving device for adjusting a beam formation azimuth through a plurality of antennas, a communication device using the same, and a method thereof.

Abstract: A device for receiving an orthogonal frequency division multiplexing (OFDM) signal includes: an ADC for converting an analog OFDM signal into a digital signal; a control device for controlling a sampling clock of the digital signal from the ADC, and detecting a symbol start point; an FFT unit for performing the fast Fourier transform on the symbol from the control device; an operation device for calculating a common phase noise and a sampling clock offset amount of the symbol from the FFT unit, outputting the compensated symbol to the channel estimation unit, and providing the sampling clock offset amount to the control device; a channel estimation unit for estimating a channel property according to the value from the operation device; and an equalizing device for compensating for distortion of the reception signal according to the estimated channel property value from the channel estimation unit.

Abstract: A fine fast Fourier transform window position recovering apparatus of an OFDM system receiver for recovering the phase error of an FFT window by using the number of zero-crossings of the phase variation value calculated between transmitted and received complex values is provided. The fine FFT window position recovering apparatus includes: an analog to digital converter, a symbol start detector, an FFT means, a phase calculator, a zero-crossing counter and an FFT window controller. The apparatus makes it possible to guarantee the reliability of a system by adjusting the phase error of the FFT window by using the number of zero-crossings of the phase variation calculated between the transmitted and received complex values and the number of the zero-crossings of the amplitude of the real part or the imaginary part of the received complex value.

Abstract: A self-aligned thin-film transistor, fabricated by depositing a conductive layer on a transparent insulating substrate, etching the conductive layer so as to form a gate electrode together with gate lines, forming a triple layer having of a gate insulating layer, a semiconductor layer and an extrinsic semiconductor layer sequentially deposited over the substrate, etching the triple layer so that only a part thereof covering the gate electrode only remains to form an active pattern, depositing a transparent conductive layer over the substrate to form a drain electrode part by etching the transparent conductive layer so that a part of the transparent conductive layer remains overlapping the gate electrode, depositing a negative photoresist over the substrate, exposing the negative photoresist to a light supplied from the back of the transparent substrate opposite the gate and developing the thus-exposed photoresist, forming a drain electrode by removing the part of a transparent conductive layer appearing in a

Abstract: A substrate for a microelectronic device is divided into at least two regions and a boundary region therebetween. The boundary region includes a first portion and a second portion. The boundary region may have subregions having equal area, and the sub-regions are arranged in a matrix shape to form the first portion and the second portion A photoresist is coated on the substrate. Portions of the photoresist on the first region and the first portion is exposed to light through a mask for photolithography, and other portions of the photoresist on the second region and the second portion is then exposed to light through the mask. The area of the sub-regions of the first portion in a column becomes larger as goes to the first region, while that of the second portion becomes smaller.

Abstract: A pair of common electrode lines are formed in the transverse direction, and a plurality of common electrodes in the longitudinal direction connect the common electrodes. Each pixel electrode parallel to the common electrodes is arranged between two of the common electrodes. A pair of connecting members which are connected to the pixel electrodes cover the edges of the common electrode lines adjacent the aperture region. Accordingly, since it is not necessary for a black matrix pattern formed in another substrate to shield the region where the liquid crystal direction does not properly behave, the black matrix lies outside the regions surrounded by the common electrodes, the pixel electrodes and the common electrode lines. In addition, the data line overlaps the adjacent common electrode, and thereby the aperture ratio is increased.

Abstract: A liquid crystal display according to this invention has at least two repair lines. A first repair line crosses twice the data lines lying on the center portion of the substrate and once the some data lines which a second repair line crosses twice among the remainings. The data lines not lying on the center portion is shorter than the remaining data lines so that they do not cross the first repair line.

Abstract: A self-aligned thin-film transistor, fabricated by depositing a conductive layer on a transparent insulating substrate, etching the conductive layer so as to form a gate electrode together with gate lines, forming a triple layer having of a gate insulating layer, a semiconductor layer and an extrinsic semiconductor layer sequentially deposited over the substrate, etching the triple layer so that only a part thereof covering the gate electrode only remains to form an active pattern, depositing a transparent conductive layer over the substrate to form a drain electrode part by etching the transparent conductive layer so that a part of the transparent conductive layer remains overlapping the gate electrode, depositing a negative photoresist over the substrate, exposing the negative photoresist to a light supplied from the back of the transparent substrate opposite the gate and developing the thus-exposed photoresist, forming a drain electrode by removing the part of a transparent conductive layer appearing in a

Abstract: A method for forming a common transfer contact of a liquid crystal display between a common electrode substrate and a thin film transistor substrate includes the steps of printing a seal pattern of a proper sealant on the common electrode substrate, assembling the common electrode substrate and the thin film transistor substrate by means of the seal pattern, cutting the common electrode substrate along a properly defined cutting line, and dotting the gap between the common electrode substrate and the thin film transistor substrate with an electrically conductive liquid-phase substance of a high viscosity to penetrate the gap by capillary action to thereby establish a common transfer contact between the common electrode substrate and the thin film transistor when being hardened.

Abstract: A reel table moving device for a video cassette tape recorder includes a mechanism for automatically positioning a pair of reel tables in response to insertion of a predetermined size video cassette without the need for an independent drive motor or sensor. The device includes a pair of protrusions mounted to opposite end portions of a moving member which are adapted to engage the tape cassette being inserted into the inlet port. The moving member moves in response to insertion of the tape cassette into the inlet port. In turn, an actuating member is connected to and moves in response to the movement of the moving member for causing the reel tables to move to a desired position for receiving a predetermined size tape cassette.

Abstract: The present invention relates to an improved method of manufacturing pads of a display panel. Al or Al alloy is deposited and patterned on a glass substrate for forming a plurality of gate electrodes and lines. Then a plurality of pads are formed with Ta or Ti, which is capable of forming an anodic oxide thereof; each pad extending over an edge of each of the respective gate lines to provide an electrical coupling therebetween. Thereafter, the entire surface of the pads, gate electrodes and lines is subjected to an anodic oxidation under a high anodization voltage. Anodic oxide layers on the pads are then etched away together with a silicon nitride layer during a subsequent pad opening processing step. Consequently, in accordance with the invention, a photoresist masking process for the selective anodic oxidation of Al gate lines and electrodes is eliminated.