Abstract: Disclosed is a differential space-time block coding apparatus with a high transmission rate in a wireless communication system employing multiple transmit antennas and a method thereof. The differential space-time block coding method includes the steps of, when elements of a transmission matrix B43v are transmitted in a predetermined block (a vth block) through a predetermined transmit antenna at a predetermined time, modulating a symbol Sv of inputted binary data to a symbol Sv+1, creating a matrix S44v+1 in a block (a (v+1)th block) following the predetermined block by substituting the modulated symbol for the matrix P44, and then, in order to perform a differential encoding function, multiplying the matrix B43v by the matrix S44v+1 so as to calculate a new matrix B43v+1 to be transmitted in the (v+1)th block.

Abstract: A method of transmitting and receiving preamble sequences in a transmitter in an OFDM communication system is provided. A transmitter segments a first sequence of a predetermined length into a predetermined number of second sequences, generates as many preamble sequences as the second sequences by applying different time offsets to the second sequences, selects a predetermined number of preamble sequences among the generated preamble sequences, maps the selected preamble sequences to the transmit antennas, and transmits the mapped preamble sequences through the transmit antennas.

Abstract: An apparatus and method for full-diversity, full-rate space-time block coding in a transmitter using two Tx antennas are provided. An input symbol sequence is STBC-encoded in a predetermined method and transmitted through the two Tx antennas.

Abstract: A method of transmitting a signal by using an Adaptive Modulation and Coding scheme in a Frequency Hopping-Orthogonal Frequency Division Multiplexing Access communication system capable of dividing total frequency bands into a plurality of sub-carrier bands and including a plurality of sub-channels, which are sets of predetermined sub-carrier bands, and a plurality of cells. The method includes the steps of allocating a predetermined number of sub-channels as AMC sub-channels per each cell matching with predetermined conditions in order to apply the AMC scheme to the AMC sub-channels, and allocating remaining sub-channels except for the AMC sub-channels as FH-OFDMA sub-channels in order to apply an FH-OFDMA scheme to the FH-OFDMA sub-channels.

Abstract: A method of forwarding a multi-hop data by which a multi-hop data frame having multi-hop information is processed, includes a mobile terminal for performing the method, and a medium access control (MAC) data structure having a multi-hop frame, which is used in the method. In the method, information is forwarded via one or more mobile terminals or a pre-installed seed to an access point, thereby allowing coverage of an access point to be extended. As a result, a communication system may be economically established, and waste of frequency resources may be reduced.

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 pilot designing method in an uplink OFDMA system is provided. In the uplink OFDMA system, communications are carried out in a frame divided into time-frequency lattices, and each time-frequency lattice includes a plurality of data symbol periods and a plurality of pilot symbol periods intermittently arranged with respect to the data symbol periods. The frame is divided into a plurality of blocks. The blocks are allocated to the terminals. A predetermined allocated pilot time-frequency lattice is shared between adjacent terminals.

Abstract: A channel estimation method in a wireless communication system based on multicarrier-code division multiple access (MC-CDMA) using frequency interleaving. A transmitter generates transmission symbols using a pilot signal (P) and an inverted pilot signal (?P) according to subcarriers on which spread symbols generated from a spectrum spreading operation are sent, performs an interleaving operation for the transmission symbols in a frequency domain, and transmits a result of the interleaving operation. A receiver extracts the pilot signal (P) and inverted pilot signal (?P) included in the transmission symbols and performs channel estimation.

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: A receiving apparatus and method for receiving signals through a plurality of receive antennas in a mobile communication system. In the receiving apparatus, a plurality of FFTs transform frequency-domain symbol sequences received from the receive antennas to time-domain FFT symbol sequences, an SIC receiver decides the value of a higher-priority transmitted symbol sequence using its FFT symbol sequence and decides the value of a lower-priority transmitted symbol sequence using the decided higher-priority transmitted symbol sequence and its error, a plurality of demodulators demodulate the decided transmitted symbol sequences to a plurality of coded bit streams, a plurality of deinterleavers deinterleave the coded bit streams, stream by stream, and a parallel-to-serial converter converts the deinterleaved coded bit streams to one coded bit stream.

Abstract: An apparatus and method for canceling interference in an OFDM system using multiple antennas, where based on error estimation of a symbol received from a receive antenna, the error of a symbol received from another receive antenna is estimated. Prior to transmission, symbols to be transmitted through a plurality of transmit antennas are shifted by a predetermined number of bits without overlapping. Thus, the effects of an error of a symbol received from a receive antenna on error estimation of a symbol received from another receive antenna are reduced.

Abstract: A communication method in an FH-OFDM communication system having a plurality of BSs is provided. A predetermined number of pilot pattern groups are generated, each pilot pattern group having a predetermined number of different pilot patterns for pilot transmission. The pilot patterns in each of the pilot pattern groups are mapped to different FH sequence sets. The pilot patterns and FH sequence sets are assigned to the BSs so that MSs within the service areas of the BSs can identify the BSs.

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: A differential STBC transmitting/receiving apparatus in a multiple antenna system using eight or less transmit antennas is provided. In the differential STBC transmitting apparatus, a symbol mapper receives binary data and generates a number of symbols from the binary data, each symbol having a number of bits. A space-time block encoder generates an STBC by encoding the symbols. A differential processor differentially encodes the STBC through feedback and delay. A distribution matrix processor substitutes the differentially coded STBC into a distribution matrix preset according to the number of transmit antennas, and outputs the differential STBC code of the distribution matrix to the transmit antennas.

Abstract: A space-time block coding method using an auxiliary symbol in a multiple transmit/receive antenna system is provided. In the space-time block coding method, binary data to be transmitted is received. Free symbols and an auxiliary symbol are generated by dividing the received binary data into units of a predetermined number of bits. The free symbols and the auxiliary symbol are encoded according to an encoding matrix and transmitted.

Abstract: In an encoding apparatus in a mobile communication system using a plurality of antennas, a puncturer punctures input coded bits in an RCP (Rate-Compatible Puncturing) method, a distributor divides the punctured coded bits by the number of the antennas depending on how many bits are punctured, an interleaver interleaves the divided coded bits, a modulator modulates the interleaved coded bits, and an arranger prioritizes the modulated symbols, arranges the modulated symbols according to priority levels, and transmits the arranged symbols through the antennas.

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: Disclosed herein is a scheduling method and apparatus based on eigen values robust against spatial correlation in a mobile communication system supporting multiple users by use of multiple transmit/receive antennas. A user terminal estimates channel characteristics from the transmit antennas to the user terminal, decomposes the estimated channel characteristics into receive channel characteristics and transmit channel characteristics, and feeds back a transmit principal eigen vector to the base station (BS). The BS selects a predetermined number of user terminals having the least correlation using the feedback principal eigen vectors from a plurality of user terminals, constructs a user precoding matrix by combining the principal eigen vectors of the selected user terminals, multiplies data streams for the selected user terminals by the user precoding matrix and transmits the multiplied data to the selected user terminals.

Abstract: A method and apparatus for determining a shuffling pattern in a DSTTD. In the apparatus, a channel estimator estimates channel characteristics from a plurality of transmit antennas to a plurality of receive antennas. A shuffling pattern selector calculates a minimum receive SNR for each of all available shuffling patterns, and selects a shuffling pattern having the largest minimum receive SNR as the optimum shuffling pattern. This efficient shuffling pattern selection directly improves BER performance at a receiver.

Abstract: A method for generating a preamble sequence in an OFDM (Orthogonal Frequency Division Multiplexing) communication system that uses A sub-carriers in a frequency domain and uses N Tx (Transmission) antennas, includes the steps of: generating N sequences, each having a length of ‘B/N’, by dividing B sub-carriers from among the A sub-carriers by the ‘N’ indicative of the number of the Tx antennas; and mapping, for each of the N sequences, individual components of the sequence to the B/N sub-carriers from among the A sub-carriers on a one by one basis in order to assign the components of the sequence to the B/N sub-carriers, and assigning null data to remaining sub-carriers other than the B/N sub-carriers from among the A-sub-carriers, such that a preamble sequence of a corresponding Tx antenna is generated.