Abstract: A light emitting diode, including a first type semiconductor layer, an active layer, and a second type semiconductor layer; an ohmic contact layer disposed on the second type semiconductor layer; a first insulating layer disposed on the semiconductor structure and including a first opening overlapping the first type semiconductor layer and a second opening overlapping the ohmic contact layer; a first connection wiring disposed on the first insulating layer, the first connection wiring having a first portion and a second portion; and a second connection wiring disposed on the first insulating layer and spaced apart from the first connection wiring, the second connection wiring electrically connected to the second type semiconductor layer through the second opening. The second connection wiring surrounds at least a portion of the first portion of the first connection wiring in a plan view.

Abstract: The present invention relates to a method and an apparatus for quantum key distribution according to a continuous-variable quantum key distribution protocol, which distributes the quantum key in a reverse post-processing manner and, after photon sub traction at a receiver (Bob), detects bit information from a received quantum state to calculate and share the quantum key, such that security can be further enhanced and a cryptographic key generation rate can be increased since the cryptographic key is not exposed to an attacker (Eve).

Abstract: The present invention relates to a method and an apparatus for quantum key distribution according to a continuous-variable quantum key distribution protocol, which distributes the quantum key in a reverse post-processing manner and, after photon sub traction at a receiver (Bob), detects bit information from a received quantum state to calculate and share the quantum key, such that security can be further enhanced and a cryptographic key generation rate can be increased since the cryptographic key is not exposed to an attacker (Eve).

Abstract: Provided is a communication method in a wireless communication system using interference alignment. The method includes: transmitting a transmission beam for separated data stream to N1 (natural number) user terminals by using M1 (natural number) antennas, by a first AP in a downlink cell; and receiving a reception beam for separated data stream from N2 (natural number) user terminals by using M2 (natural number) antennas, by a second AP in an uplink cell, wherein the first AP transmits linear independent transmission beams to improve a degree of freedom while the second AP simultaneously receives orthogonal reception beams, by simultaneously reflecting interference alignment between two cells including downlink and uplink cells.

Abstract: Disclosed are a polyethylene microporous film and a method of preparing the same. The polyethylene microporous film, which has a laminated structure comprising B layer/A layer/B layer, prepared by melt-mixing a polyethylene and an aliphatic hydrocarbon solvent together at controlled mixing ratios to separately form an A layer and a B layer having different porosities, and then coextruding the A and B layers, thus exhibiting excellent mechanical properties, such as strength and elongation, and high-temperature stability. Therefore, the polyethylene microporous film is suitable for use in a rechargeable battery separator.

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 signal detection in a Broadband Wireless Access (BWA) system are provided, in which in a transmitter, a first preamble sequence generator generates preamble sequences, a low-Peak-to-Average Power Ratio (PAPR) preamble sequence selector selects a first low-PAPR preamble sequence from among the generated preamble sequences, a preamble sequence copier copies the first low-PAPR preamble sequence at least once and outputs the first low-PAPR preamble sequence and the at least one copy, a complex conjugator generates preamble sequences orthogonal to the first low-PAPR preamble sequence and the at least one copy by calculating complex conjugates of the first low-PAPR preamble sequence and the at least one copy, and a second preamble sequence generator generates at least one second low-PAPR preamble sequence using the first low-PAPR preamble sequence.

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 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: 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: 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 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: Disclosed are a polyethylene microporous film and a method of preparing the same. The polyethylene microporous film, which has a laminated structure comprising B layer/A layer/B layer, prepared by melt-mixing a polyethylene and an aliphatic hydrocarbon solvent together at controlled mixing ratios to separately form an A layer and a B layer having different porosities, and then coextruding the A and B layers, thus exhibiting excellent mechanical properties, such as strength and elongation, and high-temperature stability. Therefore, the polyethylene microporous film is suitable for use in a rechargeable battery separator.

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: 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 equivalent to the reference preamble sequence is generated 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: 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 mobile communication system receives a reception signal, and determines a first error value by using a first scheme, and a second error value by using a second scheme, and determines a first scheme application weight according to a difference between the first error value and the second error value, and a second scheme application weight according to the difference between the first error value and the second error value, and generates a third error value using a scheme that combines the first scheme to which the first scheme application weight is applied and the second scheme to which the second scheme application weight is applied, and determines a reception beam weight using the reception signal, the third error value, and an output signal generated by applying the reception beam to the reception signal, wherein the reception beam weight is used for generating the reception beam.

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: 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.

Abstract: A mobile communication system and method utilizing Orthogonal Frequency Division Multiplexing (OFDM) receives channel quality information (CQIs) for subcarriers through which reference signals are transmitted and subcarriers through which data signals are transmitted, in subbands, each including a predetermined number of subcarriers among a plurality of the subcarriers. The CQIs are received from respective receivers. Resources are dynamically assigned to the respective receivers according to the feedback CQIs, thereby enabling dynamic resource assignment with minimized signaling overhead.