Abstract: A method for generating a preamble sequence in an orthogonal frequency division multiplexing (OFDM) communication system having A subcarriers in a frequency domain. The method comprises generating a length -M×N preamble sequence, where M×N is less than A, by using a length-N Golay complementary sequence and a length-M Golay complementary sequence; and assigning elements constituting the preamble sequence to M×N subcarriers among the A subcarriers on a one-to-one mapping basis, assigning null data to the remaining subcarriers excluding the M×N subcarriers from the A subcarriers, and then IFFT-transforming the assigned result into time-domain data.

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: A column select circuit in a Static Random Access Memory (SRAM) having a three-dimensional layout can include a lower CMOS layer in a substrate and an upper NMOS layer above the lower layer. An intermediate PMOS layer is located between the upper NMOS layer and the lower CMOS layer.

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: A method for transmitting a signal by a transmitter in a frequency overlay communication system. The method includes generating y first signal groups by shuffling input information data with a length yN on an N-by-N grouping basis according to a first shuffling scheme; generating y second signal groups by performing N-point IFFT on each of the first signal groups; generating y third signal groups by multiplying each of the second signal groups by preset values; generating N fourth signal groups by de-shuffling the third signal groups on a y-by-y grouping basis according to a de-shuffling scheme; generating N fifth signal groups by performing y-point IDFT on each of the fourth signal groups; generating y sixth signal groups by shuffling the fifth signal groups according to a second shuffling scheme, and serial-converting the sixth signal groups; and performing a transmission RF process on the serial-converted signal and transmitting the RF-processed signal to a receiver.

Abstract: A method of controlling an integrated circuit (IC) capable of simultaneously performing a data read operation and a data write operation is provided. The method comprises (a) receiving a write address, a read address, and write data, (b) determining, a memory block and a data memory block in which a data read operation and a data write operation are to be performed in response to the write address and the read address, (c) performing the data read operation or the data write operation in the data memory block according to the determination of step (b), and (d) performing the data read operation or the data write operation in the memory block according to the determination of step (b).

Abstract: A system for performing cell acquisition in a frequency overlay communication system having a first frequency band and a second frequency band including the first frequency band. A base station (BS) generates a reference signal used for identifying a cell using a specific sequence in a predetermined frequency band, and transmits the reference signal. A mobile station (MS) receives the reference signal to determine whether the BS uses the first frequency band or the second frequency band, determines a reference signal having a maximum correlation value through correlation calculation with at least one predefined sequence, and detects a BS identifier (ID) corresponding to the determined reference signal.

Abstract: A ranging apparatus in a communication system is provided. A terminal generates a ranging code for ranging with a base station, maps the ranging code to at least one sub-carrier so the ranging code is repeated in a time domain, generates a ranging signal so the mapped ranging code has a size of one symbol interval, and transmits the generated ranging signal to the base station. The base station receives a ranging signal, extracts a half signal of a valid symbol interval of the ranging signal, generates a valid symbol interval signal by repeating the extracted half signal of the valid symbol interval, restores a ranging signal using the valid symbol interval signal, and performs ranging using the ranging signal.

Abstract: An apparatus and method for reducing pilot overhead in a broadband wireless communication system are provided. A data symbol mapper maps data symbols to be transmitted into subcarriers and detects values of the data symbols mapped into predefined subcarriers. A pilot generator determines masking codes for each pilot group by using the detected values of the data symbols and masks the determined masking codes into pilot symbols of the corresponding pilot group. A pilot symbol mapper maps the masked pilot symbols received from the pilot generator into subcarriers.

Abstract: A method for performing an initial operation of a mobile station (MS) that uses a first frequency band, in a frequency overlay communication system having the first frequency band including a plurality of sub-frequency bands. The method includes performing correlation on a full frequency band in units of the first frequency band, receiving broadcast information through a frequency band having a maximum correlation value, and performing an initial access to a base station (BS) through the frequency band having the maximum correlation value if a frequency bandwidth of the BS acquired from the broadcast information is narrower than or equal to a selected frequency bandwidth of the MS.

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: An apparatus and method for transmitting/receiving a multi-functional preamble signal in a wireless communication system are provided. In an apparatus for transmitting a preamble signal in a wireless communication system, a first generator generates a predetermined ZAC sequence. A circular shifter circular-shifts the ZAC sequence according to a BS ID. A second generator generates a sequence in which samples of the ZAC sequence alternate with samples of the circular-shifted sequence. A repeater generates a baseband preamble signal by repeating the sequence received from the second generator.

Abstract: Provided is a method and apparatus for transmitting/receiving data in a frequency overlay communication system. A transmitter generates a data stream for data transmission, and performs Inverse Fast Fourier Transform (IFFT) on the generated data stream according to a predetermined first frequency band before transmission. Upon receiving a particular signal, a receiver performs Fast Fourier Transform (FFT) on the received signal according to a predetermined second frequency band, and restores the received signal.

Abstract: A frequency overlay communication system that includes a first communication system for performing communication using a first frequency band being a preset bandwidth; and a second communication system for performing communication using a second frequency band being a second preset bandwidth, wherein the second frequency band includes the first frequency band.

Abstract: Provided is a fiber ring laser capable of obtaining a back-up laser light and standard light having a wavelength continuously tuned in a single mode with equal spacing of 12.5 GHz, 25 GHz, 50 GHz or 100 GHz recommended by ITU-T Recommendation G. 692 & G. 694.1 in a C-band and an L-band using a fiber tunable etalon filter, an air gap etalon filter and a saturable absorber in an optical fiber laser resonator having a serial ring shape using a C-band optical amplifier and an L-band optical amplifier. The fiber ring laser can generate laser light having a wavelength tuned by more than 70 nm, excellent output power flatness and a source spontaneous emission ratio of more than 70 dB in 361 channels with equal spacing of 25 GHz by applying a bias voltage to a voltage-operated piezoelectric element of a tunable etalon filter. A single longitudinal mode operation of the fiber ring laser can be obtained by using a saturable absorber serving as a narrow-bandwidth filter.

Abstract: Memory devices are provided which are capable of performing burst operations by simultaneously writing/reading a plurality of data bits to/from memory in response to a selection of a single wordline, and which are capable of controlling data input/output for interruption of burst operation interruptions without having to employ complex control circuitry.

Abstract: In multicarrier communication system using N subcarriers, in which a transmitter communicates with K receivers, the transmitter determines a channel quality information (CQI) feedback quantity indicative of the number of subcarriers for which CQIs will be fed back among the N subcarriers, for the K receivers, and transmits the CQI feedback quantity to the K receivers. Thereafter, upon receiving CQIs corresponding to the determined CQI feedback quantity, being fed back from the K receivers, the transmitter allocates subcarriers for which there are CQIs being fed back from at least one receiver among the K receivers among the N subcarriers, to any one receiver among the receivers that have fed back CQIs according to a first scheme, thereby guaranteeing the maximum throughput and the maximum fairness.

Abstract: A column select circuit in a Static Random Access Memory (SRAM) having a three-dimensional layout can include a lower CMOS layer in a substrate and an upper NMOS layer above the lower layer. An intermediate PMOS layer is located between the upper NMOS layer and the lower CMOS layer.

Abstract: A fingerprint code structure and a collusion customer identifying method using the same are disclosed. The collusion customer identifying method includes the steps of: inserting a fingerprint code including a contents code and a customer code in a contents; extracting the fingerprint code; determining whether there is an collusion attack on the contents by using the extracted fingerprint code; and identifying the collusion customers participating in the collusion attack according to a result of the determination. The collusion customer identifying method can trace collusion customers participating in the collusion attack by using a location of undetectable code although the collusion customers eliminate the fingerprint code from the multimedia contents by participating in the collusion attack.

Abstract: A transmitting and receiving apparatus and method for optimizing performance of an adaptive modulation and coding (AMC) in a multiple input and multiple output antenna (MIMO) communication system. When the AMC is applied to the MIMO system, the optimal scheme is different depending on the MIMO channel situation, the maximum transmission power, and the maximum modulation order. The transmitting apparatus includes an ordering selector that selects a successive interference cancellation (SIC) scheme in order to obtain a maximum MIMO-AMC performance, and the receiving apparatus includes a channel quality information (CQI) generator corresponding to the SIC scheme selected at the transmitting apparatus.