Abstract: Disclosed is a system and method for modulating a pilot symbol sequence in a multi-carrier communication system. The method including producing a pilot symbol sequence corresponding to a predetermined time interval by removing a data symbol sequence from time domain signal to be transmitted, the time domain signal including the data symbol sequence and the pilot symbol sequence; and modulating the pilot symbol sequence so that a part of the time domain signal corresponding to a predetermined number of pilot symbols in the pilot symbol sequence has a predetermined pattern.

Abstract: A true bit line can extend across a memory cell area of the memory device in a first direction and a complementary bit line can extend across the memory cell area in a second direction opposing the first direction, wherein the true bit line and the complementary bit line comprising a bit line pair.

Abstract: An apparatus and method for estimating and correcting an uplink frequency offset in an OFDM communication system are provided. A subscriber station (SS) once repeats an OFDM symbol including a ranging code allocated from a BS and transmits the repeated OFDM symbols to the base station (BS). The BS demodulates the two successive OFDM symbols received from the SS using the ranging code, sums the demodulated signal for each FFT window, and estimates the uplink frequency offset by multiplying the complex conjugate of a sum for a first FFT window by a sum for a second FFT window by the base station. The BS transmits a message including information about the frequency offset estimate to the SS. The SS then corrects the uplink frequency offset using the frequency offset information.

Abstract: A subcarrier assignment apparatus and a subcarrier assignment method, in which each of a plurality of Base Stations (BSs) constituting an Orthogonal Frequency Division Multiple Access (OFDMA) communication system provides services in the capacity of a serving BS to Mobile Stations (MSs). Channel quality information for the respective MSs are fed-back from the respective BSs. Subcarriers are assigned to the respective MSs according to a corresponding scheduling scheme in consideration of the channel quality information for the respective MSs, which are fed-back from the respective BSs, and then BSs which manage the subcarriers assigned to the respective MSs according to the corresponding scheduling scheme are selected. These operations provide site diversity to each of the MSs, and thus system capacity is maximized.

Abstract: An elevator system without a machine room is disclosed. In this elevator system without a machine room according to the present invention, a built-in winding apparatus is installed in the interior of a hoistway for moving an elevator car. In addition, the elevator system without a machine room according to the present invention is characterized in that a movement stroke of a counterweight is shorter than a movement stroke of an elevator car, and a reinforcing installation member is installed across an upper portion of a pair of counterweight guide rails which corresponds to an upper counterweight moving distance, and a pair of counterweight guide rails are integral with the reinforcing installation member, and the built-in winding apparatus is installed on the reinforcing installation member in such a manner that the elevator car is moved by a driving force transferred by a motor roping unit.

Abstract: Integrated circuit memory devices include a first column of memory cells electrically coupled to a first pair of bit lines and a bit line precharge and selection circuit. This bit line precharge and selection circuit includes at least one stacked arrangement of thin-film transistors. These thin-film transistors include a first PMOS thin-film pull-up transistor and a first NMOS thin-film pass transistor. These thin-film transistors are electrically coupled to one of the first pair of bit lines. The first column of memory cells includes a column of TFT SRAM cells.

Abstract: A method for designing an optimum STC in an HARQ system is provided, in which kth codes are detected which maximize the minimum squared Euclidean distance of the signal matrix of a combination code created by combining first to (k?1)th codes with a kth code. A kth code whose signal matrix has a maximum minimum determinant is selected as the kth retransmission code.

Abstract: The present invention relates to a biaxially stretched, laminated, white microporous polyester film, which can be used in a wide range of industrial applications including printing, imaging, advertising and display. The film of the present invention comprises a porous polyester resin layer B containing a thermoplastic resin non-compatible with polyester; a polyester resin-based photic layer A formed on one surface of the resin layer B, the photic layer A having a 60-degree gloss of the surface thereof of more than 100%; and an aphotic layer C formed on the other surface of the resin layer B, the aphotic layer C having a 60-degree gloss of the surface thereof of less than 50%. The total density of the photic layer A and the aphotic layer C is 0.55–1.2 g/cm3. This film has excellent gloss and flexibility so that it is very suitable for use in printing and imaging.

Abstract: Disclosed are the design and implementation of a CSI feedback channel in a multi-carrier wireless communication system. An apparatus and a method for channel state feedback using arithmetic coding are provided to ensure efficiency and reliability of a system by transmitting the CSI while compressing the CSI with a predetermined compression rate selected depending on a channel state. The apparatus for CSI feedback in a wireless communication system performing channel estimation at a transmitter or a receiver by using a communication channel includes a transmitter terminal transmitting a signal for CSI measurement by using the communication channel, and a receiver terminal receiving the signal from the transmitter terminal, checking a channel state based on the received signal, and transmitting the signal to the transmitter terminal after compressing the signal according to the channel state.

Abstract: An apparatus and method for generating an octal code for identifying cells in a mobile communication system. In the octal code generating apparatus, a binary code generator generates a binary code with a predetermined minimum Hamming distance. A column permutator permutes the order of columns of the binary code in a predetermined interleaving method. A 3-bit combiner generates a plurality of codewords using the column-permuted binary code as a generator matrix and groups the bits of each of the codewords by threes. An octal code generator converts the 3-bit grouped binary codewords to octal code sequences.

Abstract: An apparatus and method for channel estimation using preamble signals received from a serving Node B and neighboring Node Bs each having N (?1) transmit antennas in a UE having M (?1) receive antennas in a broadband wireless communication system. In the channel estimation apparatus, a Node B number decider calculates the maximum number NS of channel-estimatable Node Bs using a preamble length, the number of antennas in each of the Node Bs, and the number of multiple paths. A multi-cell preamble matrix generator generates a multi-cell preamble matrix xS by generating a Node B preamble matrix for each of the Node Bs and selecting NS Node B preamble matrices according to reception power among the Node B preamble matrices. A channel estimator performs a channel estimation using xS and signals received through the M antennas during a preamble receiving period.

Abstract: A semiconductor memory device and a method of operating the semiconductor memory device are disclosed. The semiconductor memory device comprises a memory cell array having a plurality of cell array blocks. The cell array blocks are operationally divided into a plurality of memory planes using a memory determining unit. Each of the memory planes comprises at least one cell array block and is capable of executing independent data access operations using an independent operating mode.

Abstract: An apparatus and method for switching between an AMC mode and a diversity mode adaptively according to a channel environment in a broadband wireless communication system are provided. According to the present invention, a transmitter (a base station) determines a transmission mode according to frequency-domain and time-domain channel measurement information received from a receiver (a mobile station). If the transmission mode is the AMC mode, the transmitter selects a coding and modulation scheme according to a frequency-domain CQI received from the receiver. If the transmission mode is a diversity mode, the transmitter selects a predetermined coding and modulation scheme.

Abstract: Provided are an apparatus and method for transmitting/receiving a pilot code pattern used to identify a base station. In the base station, a pilot code pattern determiner determines a code set that includes a number of spreading codes based on a specific ID of the base station. A first spreader spreads a pilot symbol mapped onto an FC with a corresponding spreading code according to the determined code set, and controls gain so as to transmit the pilot symbol at a higher signal level than data. A second spreader spreads data symbols mapped onto the FC with spreading codes of the code set except for the spreading code used for the pilot spreading. A mapper groups a spread signal from the first spreader and spread signals from the second spreader on a TFC basis, and outputs signals that constitute each TFC to points of sub-carriers. An IFFT unit performs an IFFT operation on signals output from the mapper. Because the pilot as well as the data is spread, it is easy to implement the base station.

Abstract: Disclosed is a method for transmitting/receiving data by use of feedback information in a closed loop multi input multi output (MIMO) mobile communication system. The method includes the steps of feeding back transmission eigenvector selection information determined through a singular value decomposition (SVD) of a channel matrix and transmitting the transmission eigenvector selection information to a transmitter; and receiving the feedback transmission eigenvector selection information, selecting transmission data according to the received transmission eigenvector selection information, mapping the selected transmission data to at least one transmission antenna, and transmitting the transmission data to a receiver.

Abstract: An apparatus and method for embedding and extracting digital watermarks using a blind mode based on wavelet transform which is robust to external attacks while being capable of minimizing a degradation in picture quality caused by embedding of the watermarks. In accordance with the invention, watermarks protection of the copyright for desired data are embedded in DC component domains of wavelet-transformed domains. In accordance with the invention, embedding of watermarks in a target image corresponding to a target domain in which the watermarks are to be embedded, is achieved by generating a data stream of the watermarks in accordance with a key value selected by the user, generating index information representing positions where the watermarks are to be embedded, in accordance with a key value selected by the ser, and reflecting the watermark data stream on data values of pixels in the target image at the positions based on the index information.

Abstract: Disclosed are an apparatus and a method for generating a preamble sequence in an orthogonal frequency division multiplexing communication system including a reference base station and a plurality of non-reference base stations and employing m sub-carriers in a frequency domain. A reference preamble sequence having a length equal to n is generated and mapped on a one-to-one basis with n sub-carriers of the m sub-carriers. A final preamble sequence is generated from a base station when the base station is a reference base station, or a phase of the reference preamble sequence is shifted by a predetermined phase in order to generate a phase-shifted final preamble sequence when the base station is a non-reference base station, thereby minimizing interference between neighbor base stations.

Abstract: A method for transmitting reference signals in a radio communication system in which a frequency band is divided into a plurality of sub-frequency bands. The reference signals are transmitted through at least one of the plurality of sub-frequency bands, and data signals are transmitted through the plurality of sub-frequency bands except for the at least one of the plurality of sub-frequency bands. The method includes the steps of: determining a reference signal pattern representing positions of the at least one of the plurality of sub-frequency bands through which the reference signals are transmitted in consideration of a preset time and a preset bandwidth; generating the reference signals using a PN code and a Walsh code; and transmitting the reference signals through the sub-frequency bands corresponding to the reference signal pattern.

Abstract: An apparatus and method for transmitting/receiving a pilot pattern set to distinguish a base station in an FDM communication system. The method divides a total frequency bandwidth into at least two sub-bandwidths including a plurality of sub-carriers in an OFDMA (Orthogonal Frequency Division Multiple Access) mobile communication system, configures a single frame cell (FC) using one sub-bandwidth from among the sub-bandwidths and a plurality of OFDM (Orthogonal Frequency Division Multiplexing) symbol intervals, and assigns a pilot signal to a time-frequency cell comprised of at least one OFDM symbol and at least one sub-carrier within the FC. The method includes the steps of spreading a pilot signal and a data signal using different orthogonal codes, synthesizing the spread pilot and data signals, and performing a CDM (Code Division Multiplexing) process; and mapping the CDM-processed pilot and data signals to a predetermined time-frequency cell in the FC.

Abstract: An apparatus and method for transmitting a reference signal in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system in which a total frequency band is divided into a plurality of subcarrier bands. A time division multiplexer performs time division multiplexing such that the reference signal is transmitted for a first duration in a predetermined number of subcarrier bands from among the plurality of the subcarrier bands, and a signal other than the reference signal is transmitted for a second duration other than the first duration. A transmitter transmits the time-division multiplexed subcarrier band signals.