Abstract: A mobile communication apparatus having an antenna array and a mobile communication method performed in the mobile communication apparatus, wherein the mobile communication apparatus includes a base station and mobile station, each having an antenna array. The mobile station measures the downlink characteristics of a channel for each antenna from a signal received from a base station, determines long-term information in which the correlation property of the channel for each antenna has been reflected from the measured downlink characteristics, transforms the long-term information into a feedback signal, and transmits the feedback signal to the base station.

Abstract: Disclosed is a mobile communication system using a Multiple Input Multiple Output (MIMO) scheme. A transmitter of the mobile communication system, generates a unitary space-time matrix to correspond to a codeword if the codeword to be transmitted in a first time interval is input, multiplies the unitary space-time matrix by a first final transmission matrix denoting signals transmitted in a second time interval before the first time interval, thereby generating a second final transmission matrix denoting signals to be transmitted in the second time interval, and transmits signals corresponding to the second final transmission matrix through a plurality of transmit antennas in the second time interval.

Abstract: A method of allocating resources to control information transmitted from a base station (BS) to a subscriber terminal in a downlink (DL) frame and the subscriber terminal for receiving the control information are provided. A preamble and a common control channel in a DL frame from a particular BS are allocated to a sub-carrier band that is different from that of a preamble and a common control channel in a DL frame from a neighbor BS, concurrently with the preamble and the common control channel of the neighbor BS. User-specific traffic in the DL frame of the particular BS is allocated to a total sub-carrier band concurrently with user-specific traffic of the neighbor BS.

Abstract: A method is provided for recognizing the frequency bandwidth of a base station in a mobile communication system with frequency bandwidth scalability where the transmission frequency bands of base stations and mobile stations having different frequency bandwidths are overlaid with one another. The base stations transmit to a mobile station first information, including information about their frequency bandwidths at the same frequency position over a minimum frequency bandwidth with the same center frequency. The mobile station recognizes the presence of the base stations by comparing the first information from the base stations and detects the frequency bandwidth information in the first information.

Abstract: A method is provided for allocating sub-channels in an Orthogonal Frequency Division Multiple Access (OFDMA) mobile communication system including a plurality of cells or a plurality of sectors. The method comprises dividing a time interval preset into a band Adaptive Modulation and Coding (AMC) sub-channel region and a diversity sub-channel region, for each of the cells or sectors; and allocating band AMC sub-channels only in a preset frequency region of the full frequency band used in the OFDMA mobile communication system, in the band AMC sub-channel region.

Abstract: Disclosed is a cellular-based wireless communication system, and more particularly a method for allocating resources for data transmission in a cellular-based wireless communication system employing a multicarrier scheme. Frequency resources are divided into time slots defined by one frame and the divided time slots are allocated to an uplink and the downlink. During a predetermined time period, the frequency resources are allocated as resources for transmitting sync preambles. During a next predetermined time period, the frequency resources are allocated in such a manner that the frequency resources for sectors are successively and repeatedly used as resources for transmitting broadcasting messages on a sector-by-sector basis. In the remaining time slots, except the time slots for transmitting the preambles and the broadcasting messages, the frequency resources are allocated as resources for transmitting channel estimation midambles for dynamic channel allocation.

Abstract: A scheduling method includes classifying, by a PC, terminals into delay-sensitive terminals and delay-insensitive terminals according to their traffic types; setting an initial value and a maximum value of a poll failure counter of each of the delay-sensitive terminals; polling each of the delay-sensitive terminals; determining whether there exists a delay-sensitive terminal of which a current value of the poll failure counter is less than the maximum value; and if there exists no delay-sensitive terminal of which the present value of the poll failure counter is less than the maximum value, sequentially polling the delay-sensitive terminals and the delay-insensitive terminals. Accordingly, QoS of voice packet transmission in an IP network can be guaranteed by granting priority to terminals generating traffic in reality according to traffic patterns of the terminals requiring strict QoS, such as a voice call service, and polling the terminals in a round robin mechanism.

Abstract: Disclosed is a method for transmitting an uplink data during handoff. A method for transmitting uplink data in a soft handoff system, in which a mobile station is simultaneously connected with at least two base transceiver systems under a control of a base station controller, includes selecting one of the base transceiver systems as a main base transceiver system, transmitting uplink signals to the main base transceiver system and sub-base transceiver systems, and transmitting by the sub-base transceiver systems received uplink signals to the main base transceiver system. Through the method, a main BTS for diversity combining and decoding soft bit strings is established among BTSs connected to a mobile station, so that it is possible to distribute a data processing amount centralized on a BSC to a BTS.

Abstract: Provided is a method of reducing a peak-to-average-power ratio in a multiple antenna orthogonal frequency division multiplexing communication system. The method includes: reducing a peak-to-average-power ratio of input serial data sequences; space-time coding the input serial data sequences with the reduced peak-to-average-power ratio to generate N symbols to be tranmitted via N antennas; receiving the serial data sequences of the N symbols to transform the serial data sequences into N parallel data sequences; allocating each of the N parallel data sequences to Ns sub-carriers and performing Inverse Fast Fourier Transform on the N parallel data sequences; transforming the N parallel data sequences into N serial data symbols; and replicating a portion of the serial data symbols to generate cyclic prefixes and interleaving the cyclic prefixes into starting portions of the serial data symbols to cyclically expand the N symbols.

Abstract: A relay communication method in an orthogonal frequency division multiple access (OFDMA) communication system including at least one base station for providing a multiple access service to a plurality of mobile stations frame by frame. The relay communication method includes dividing a cell defined by transmission power of the base station into a plurality of sectors on the basis of the base station; dividing the cell into an inner area where a first service is supported and an outer area where a second service is supported, on the basis of the base station; arranging at least one relay station in a second service area of each sector; and allocating a partial resource of the frame for communication between the base station and the mobile station through the relay station.

Abstract: A method for transmitting to one cell a frame including broadcast channels in a cellular wireless communication system in which a base station supports a plurality of physical channels corresponding to the broadcast channels. The base station generates the frame and transmits the generated frame to a mobile station. The frame includes separate broadcast channels for the respective physical channels. A position, in the frame, of a first broadcast channel for a physical channel capable of supporting a mobile station having the worst channel state is fixed in all of transmission frames. The first broadcast channel includes positional information of the remaining broadcast channels except for the first broadcast channel. The mobile station detects only an address of a broadcast channel for a physical channel allocated thereto from the first broadcast channel among broadcast channels belonging to the frame.

Abstract: A data communication apparatus and method based on orthogonal frequency division multiple access (OFDMA) are provided. In the data communication apparatus, a (U+1)-th encoder in a u-th user transmitting unit among U user transmitting units which transmit corresponding user information to a base station part encodes the user information and outputting the result of encoding as Nu u-th user symbols. A user signal generator generates a u-th user signal xk(u) in a temporal domain from the u-th user symbol Am(u) received from the (U+1)-th encoder according to a formula, xk(u)=ak % Nu(u) exp(j2?knu/N). A second cyclic extension symbol inserter inserts a cyclic extension symbol into the u-th user signal. A second signal transmitter converts the result of insertion into a symbol block signal and transmitting the symbol block signal to the base station part. Here, 1?NU<N. Accordingly, the hardware of a user part can be optionally simplified very much.

Abstract: A virtual cell management apparatus and method using sectors in an orthogonal frequency division multiplexing mobile communication system including a cell structure having cells each comprised of a plurality of sectors, the cells performing data communication with mobile terminals within a corresponding cell through at least one subchannel having orthogonality.

Abstract: A method for switching a current duplexing mode of a mobile station in a cellular system in which a base station supports multiple duplexing modes. The method includes determining if it is necessary to switch the current duplexing mode of the mobile station in a predetermined scheduling period, and switching the current duplexing mode of the mobile station when there are available wireless resources for a target duplexing mode into which the mobile station wants to switch the current duplexing mode.

Abstract: In an orthogonal frequency division multiplexing (OFDM) mobile communication system, an apparatus and method allocates resources for data transmission and transmits/receives user data using the allocated resources. A full subcarrier band allocable for one cell is divided into a plurality of subcarrier regions. Subcarriers selected from subcarriers existing in one of the plurality of subcarrier regions are allocated for each of a plurality of sectors constituting the cell. The subcarriers are allocated such that subcarriers existing in different subcarrier regions are allocated for neighboring sectors in the cell.

Abstract: A mobile communication apparatus having multiple transmission antennas and multiple reception antennas and a mobile communication method used in the mobile communication apparatus, wherein a base station, which has at least one reception antenna, restores long-term and short-term information determined in consideration of first characteristics in a mobile station, which has at least one transmission antenna, from a feedback signal received from the mobile station, spatially processes dedicated physical channel signals using basis information produced from the restored long-term and short-term information, and transmits the results of addition of the spatially-processed signals to pilot signals to the mobile station, wherein the first characteristics are the characteristics of the downlink channels of the respective transmission and reception antennas.

Abstract: Disclosed is a method for uplink scheduling in a communication system. The method for uplink scheduling in a communication system having a cellular structure hopping between sub-channels according to a predetermined rule whenever a signal is transmitted The communication system dividing a whole frequency band into a plurality of sub-carrier bands and including the sub-channels which are sets of the sub-carrier bands.

Abstract: Disclosed is a symbol synchronization method in an OFDM-based communication system which includes multiple access nodes supporting wireless connection of terminals, supports multi-connection of each terminal for the access nodes and performs synchronization by means of a cyclic prefix. The symbol synchronization method includes monitoring connection of a new access node; setting a number of times by which the new access node transmits equal symbols and a number of times by which at least one existing access node transmits the equal symbols when the connection of the new access node is detected; transmitting the equal symbols by the determined number of times by each access node; and performing synchronization by means of the symbols received from the access nodes by the terminal.

Abstract: A method and apparatus for transferring channel information in OFDM communications are provided. In the channel information transmission apparatus, a receiving portion includes a prefix remover removing a prefix, attached to the OFDM signal in order to overcome channel fading, from an OFDM signal received from a transmission portion, a fast Fourier transformer transforming a received time domain signal from which the prefix has been removed into a frequency domain signal, a channel measurer extracting a channel value from the frequency region signal obtained by the fast Fourier transformer, a compensator compensating for the output signal of the fast Fourier transformer using the channel value obtained by the channel measurer, a parallel-to-serial converter converting a compensated parallel signal received from the compensator into a serial signal, and a signal processor processing the channel value measured by the channel measurer in order to transmit signal-processed data to the transmission portion.

Abstract: A method for transmitting orthogonal frequency division multiplexing (OFDM) signals including coding the OFDM signals; forming a block of N coded data and dividing the block into L M-sized small blocks; M-point inverse fast Fourier transforming the L small blocks; combining the transformed blocks to generate an N-sized inversely-transformed block; attaching a cyclic prefix to the N-sized block; and transforming the blocks into an analog signal; and transmitting the analog signal. A method of receiving OFDM signals including digitally converting received OFDM signals and obtaining a samples from the transformed signals; detecting the starting point of an N-sized signal sample block from the samples; dividing the signal sample block into L M-sized small blocks M-point fast Fourier transforming the L small blocks; combining the transformed small blocks to generate an N-sized transform block; detecting data from the generated block, and decoding the detected data. N, M and L are integers of 1 or more and L=N/M.