Abstract: Disclosed is a method for acquiring synchronization in a mobile communication system using an Orthogonal Frequency Division Multiplexing (OFDM) scheme. The method includes modeling a power delay profile in time-varying frequency selective fading channel conditions by a specific function; detecting a log probability distribution function of a timing offset and a frequency offset in consideration of a correlation between a received signal and the received multi-path signal in the time-varying frequency selective fading channel conditions having the power delay profile modeled as the specific function; and estimating a timing offset and a frequency offset which maximize the log probability distribution function of the timing offset and the frequency offset.

Abstract: An apparatus and a method for efficient resource allocation using a cognitive radio communication in Orthogonal Frequency Division Multiple Access (OFDMA)-based moving networks are provided. The method includes determining a minimum transmit power value of the MRS, which enables the internal terminal to have a receive Signal to Interference and Noise Ratio (SINR) greater than a first threshold; determining a transmit power value of the MRS by taking into account the determined minimum transmit power value; determining a transmit power value of the MRS per cellular terminal, which is transmittable at maximum while exerting interference less than a second threshold on a corresponding cellular terminal; searching one or more cellular terminals having the maximum transmittable transmit power value determined per cellular terminal greater than the determined transmit power value; and borrowing and allocating a resource allocated to the searched cellular terminal to the internal terminal.

Abstract: An interface device for an optical recording and/or reproducing apparatus for recording and playback of an optical disc, wherein the configuration of an interface circuit between a pickup that reads and writes information from/on the optical disc and a radio frequency (RF) integrated circuit (IC) for signal processing is simplified. To this end, the interface device includes a pickup, an integrated circuit, and a multiplexer. The pickup drives a plurality of laser diodes generating laser signals to record and/or reproduce information on a plurality of discs, respectively, and receives the laser signals reflected from the discs and output photodiode (PD) signals corresponding respectively to the received laser signals. The integrated circuit controls outputs of the laser diodes, and processes the PD signals from the pickup.

Abstract: Disclosed herein is an echo cancellation and echo channel estimation system that can relay transmit signals without interference with echo signals by canceling the undesired echo signals received by a relay. The echo cancellation and echo channel estimation system is designed to relay signals between a transmitter and a receiver through a relay using multiple antennas. The echo cancellation and echo channel estimation system includes a receive antenna, a preprocessing vector generation module, an echo cancellation module, and a transmit array antenna. The receive antenna receives a transmit signal from the transmitter and an echo signal via an echo channel. The preprocessing vector generation module generates a preprocessing vector and applies the preprocessing vector, the transmit signal and the echo signal, received from the receive antenna, to the echo cancellation module.

Abstract: A method of setting a packet transmission path in a wireless communication network and a network apparatus using the same are provided. A method of setting a packet transmission path includes setting N?1 routing regions including at least one node between a source node and a destination node based on a predetermined N number of hops, N denoting an integer greater than or equal to two, and determining a node in each of the routing regions as a relay node based on a channel gain.

Abstract: A microactuator including a base frame; and a moving plate having both ends supported by a plurality of elastic support portions inside the base frame, the moving plate having a first side on which a reflective mirror for changing a light path is disposed. At least one first rib is disposed along an edge of a second side of the moving plate, which is the reverse side of the first side of the moving plate, and a second rib is disposed in the center of the second side of the moving plate and correspondingly encloses a permanent magnet. Also, a portion of the second side of the moving plate, except for the first and second ribs, is removed to a predetermined depth to reduce the weight of the entire moving plate and to define the first and second ribs.

Abstract: In a method for feeding back combination information of transmitted signals in a multiple-input multiple-output (MIMO) system using a multiple space-time block coding technique, mean square error values are computed in relation to the combination information pieces of the transmitted signals. An index of a combination having a minimum mean square error value from among the mean square error values is fed back.

Abstract: A disk drive including a tray and an opener. The tray includes a disk cartridge mounted thereon and is loaded into and unloaded from a main body. The opener is installed in the main body and elastically contacts a guide formed on the tray. The opener includes a second gear and a first protrusion. The second gear rotates a rotating wheel when in contact with a first gear. The first protrusion formed on a first end of the second gear temporarily rotates the rotating wheel so that the first and second gears can mesh. The guide has a first cam that moves the opener such that the first protrusion does not interfere with the latch when the tray is loaded/unloaded.

Abstract: An actuator used with an optical pickup includes: a base on which a holder is fixed; a lens holder in which a plurality of installation holes are formed such that a plurality of objective lenses to record and/or reproduce optical discs having different recording densities are installed at different heights; a support member, which movably supports the lens holder, having one end coupled to the lens holder and the other end coupled to the holder; and a magnetic circuit which drives the lens holder in focusing and tracking directions. The plurality of installation holes include a first installation hole in which a first objective lens for at least one type of low density optical disc is installed, and a second installation hole in which a second objective lens for a higher density optical disc than the low density optical disc is installed.

Abstract: An apparatus and a method for canceling interference using a space-frequency block coding in a multi-antenna system. The method includes confirming a code for coding to minimize a Pairwise Error Probability (PEP) of a transmit signal of which the PEP is maximized according to a time variation; and coding the transmit signal with the code and transmitting the coded signal via at least two antennas. Accordingly, the interference cancellation can be accomplished while lowering the complexity of the receiver without degrading the spectral efficiency.

Abstract: An actuator used with an optical pickup includes: a base on which a holder is fixed; a lens holder in which a plurality of installation holes are formed such that a plurality of objective lenses to record and/or reproduce optical discs having different recording densities are installed at different heights; a support member, which movably supports the lens holder, having one end coupled to the lens holder and the other end coupled to the holder; and a magnetic circuit which drives the lens holder in focusing and tracking directions. The plurality of installation holes include a first installation hole in which a first objective lens for at least one type of low density optical disc is installed, and a second installation hole in which a second objective lens for a higher density optical disc than the low density optical disc is installed.

Abstract: An apparatus for adaptively modulating/demodulating signals in a multi-input multi-output (MIMO) system having a layered time-space architecture detector and a method thereof is disclosed. The apparatus includes: a bit and power allocation information calculator for deciding an equivalent channel gain in a reverse order of Vertical-Bell laboratories Space Time (V-BLAST) based on MIMO channel information feedbacked from a receiver and determining the number of bits and transmission power to be transmitted to each transmitting antenna by using the equivalent channel gain; and adaptive modulation means for modulating signal of each layer with corresponding modulation method based on the determined number of bits and transmitting power, controlling the transmitting power and transmitting the adaptively modulated signal through each transmitting antenna.

Abstract: A disk player has a tray capable of moving in and out of a player body. A driving unit moves the tray. A lift unit selectively engages or disengages the driving unit and raises a turntable receiving a disk loaded by the tray thereon. A spindle motor rotates the turntable. A damping unit reduces loads and impacts during movement of the lift unit.

Abstract: In the ICI cancellation method for OFDM communication system, a receiver performs channel estimation using pilot subcarriers included in transmission signals transmitted from at least one transmitter. The transmitter generates the transmission signal in which pilot subcarriers and data subcarriers are regularly arranged, performs preceding on the transmission signal, modulates the pre-coded transmission signal into an OFDM symbol, and transmits the OFDM symbol. The receiver receives the OFDM symbol; demodulates the OFDM symbol, detects the pilot subcarriers from a demodulated signal, estimates channels using the pilot subcarriers, and restores the transmission signal using the estimated channels.

Abstract: Disclosed is a data transmission/reception method and system for minimizing intercarrier interference (ICI) in a communication system using a multicarrier. The data transmission method by a transmitter includes grouping transmission signals in units of a predetermined number of transmission signals when the transmitter has received the transmission signals, multiplying each group of the transmission signals by a transmission coding matrix, and transmitting the transmission signals multiplied by the transmission coding matrix to a receiver.

Abstract: An optical disk player with improved opening and closing of a door, transport of a tray, and an improved pivoting structure of a chassis to pivot a turntable. The optical disk player includes: a body; a tray to move in and out of the body so as to transport an optical disk; a chassis installed to pivot inside the body; an optical pickup, which is installed to be able to move back and forth in the chassis, to record/reproduce information onto/from the optical disk that is rotatably placed on the turntable; a cover installed on a front of the body, the cover including: a door holder with an aperture through which the tray moves; a door to be able to slide along the door holder so as to open and close the aperture; and a cam driving device to activate the tray, to pivot the chassis, and to open and close the door by sliding.

Abstract: A disc recording/reproducing apparatus includes a main frame, a disc cartridge including a case with an opening on a bottom thereof to expose a disc-type recording medium and a window on a sidewall thereof, a shutter mounted in the case to expose and cover the opening, a rotary wheel operating in association with the shutter, and a latch unit formed at one side of the case to control rotation of the rotary wheel, a tray mounting the disc cartridge and moving with respect to the main frame, a shutter opening/closing unit connected to one side of the main frame, a rack member of a cantilever type contacting with the rotary wheel, and first and second connection ribs connected to a static part of the shutter opening/closing unit, and a cam guiding the rack member distanced in relation to or from the latch unit, during shutter opening/closing operations.

Abstract: An adaptive modulation scheme relating to an RA problem for maximizing the transmission rates of all users for maximum transmission rates in an OFDMA system including some users requiring to use services at fixed data rates. The scheme proposes introduction of an adaptive modulation using linear programming into an existing scheme for a system including a single kind of users, thereby enabling simultaneous execution of the adaptive modulation for all users in a system including two kinds of users. Further, the invention proposes another scheme of sequentially allocating subchannels to the users when the fixed transmission rate has a sufficiently small value, in order to reduce the complexity.

Abstract: Disclosed is an apparatus and a method for signal transmission and reception according to a pre-processing scheme in a MIMO mobile communication system. The method includes: inputting a symbol; and pre-processing the input symbol according to a pre-processing matrix corresponding to pre-processing matrix information and transmitting the pre-processed symbol through a corresponding transmission antenna, wherein the pre-processing matrix is determined in accordance with a number of transmission antennas and a rate used in the MIMO mobile communication system.

Abstract: An optical pickup actuator includes a blade, on which an objective lens is mounted, arranged so as to flexibly move by a plurality of suspension wires; magnets facing each other in a tangential direction, wherein the blade is between the magnets, first coils arranged in pairs on two sides of the blade in the tangential direction for focus driving and radial tilt driving, a pair of second coils arranged on two sides of the blade in the tangential direction for track driving, and a pair of third coils arranged on two sides of the blade in a tracking direction for tilt driving of the tangential direction. The optical pickup actuator is driven in four axes.