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: 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 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.

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: 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: 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: 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: 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: 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 fed back 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.