Abstract: Provided are a multi-dimensional detector for a receiver of an MIMO system and a method thereof. The multi-dimensional detector includes a first symbol detecting unit for calculating symbol distance values using an upper triangular matrix (R) obtained from QR decomposition to detect an mth symbol; a symbol deciding unit for deciding a symbol having a minimum distance value among the calculated symbol distance values from the first symbol detecting unit; and a second symbol detecting unit for calculating symbol distance values using an updated received signal y and the upper triangular matrix R to detect a (m?1)th symbol.

Abstract: Provided are a receiving apparatus for a multiple input multiple output (MIMO) system and a method thereof. The receiving apparatus includes a QR decomposing unit for calculating a single (Q) matrix vector and an upper triangle (R) matrix vector for a receiving signal vector; a first symbol estimation unit for estimating predetermined symbols using the calculated Q matrix vector and R matrix vector; a log likelihood ratio (LLR) calculating unit for calculating log likelihood ratios of unit bits for the estimated symbols; an interference removing unit for receiving a decoded signal that is decided using the calculated log likelihood ratios and removing interference from the receiving signal vector; and a second symbol estimation unit for linearly estimating remaining symbols for the interference removed signal.

Abstract: Provided is a QR decomposition apparatus and method that can reduce the number of computers by sharing hardware in an MIMO system employing OFDM technology to simplify a structure of hardware. The QR decomposition apparatus includes a norm multiplier for calculating a norm; a Q column multiplier for calculating a column value of a unitary Q matrix to thereby produce a Q matrix vector; a first storage for storing the Q matrix vector calculated in the Q column multiplier; an R row multiplier for calculating a value of an upper triangular R matrix by multiplying the Q matrix vector by a reception signal vector; and a Q update multiplier for receiving the reception signal vector and an output of the R row multiplier, calculating an Q update value through an accumulation operation, and providing the Q update value to the Q column multiplier to calculate a next Q matrix vector.

Abstract: Provided is a reception apparatus and method of a Multiple Input Multiple Output (MIMO) system that receives a plurality of different data streams in a multiple cell environment. The reception apparatus for receiving a plurality of different data streams in a multiple input multiple output (MIMO) antenna system includes a data stream detector for detecting each data stream by removing interference between the different data streams while maintaining channel information; and a cochannel interference (CCI) remover for removing cochannel interference from each data stream detected in the data stream detector. The present invention can remove cochannel interference and increase channel capacity to thereby acquire both diversity gain and multiplexing gain.

Abstract: Provided are a receiver of a Multiple Input Multiple Output (MIMO) system, QR decomposition and multi-dimensional detection used in the receiver. The receiver includes: a QR decomposing unit for performing a QR decomposing operation in cycles 1 to nT-n?1, and performing a column exchanging operation in cycles nT-n to nT as QR decomposition where n and T are an integer number; and a multi-dimensional detecting unit for receiving a first R matrix Ry and a second R matrix Rz from the QR decomposing unit, calculating a first distance value for detecting an mth symbol for the first R matrix and a second distance value for detecting an mth symbol for the second R matrix, and simultaneously detecting an mth symbol and an (m?1)th symbol using the first distance value and the second distance value.

Abstract: Provided are a QR decomposition apparatus and method for a MIMO system. The QR decomposition apparatus includes: a norm calculator for calculating a vector size norm for a channel input; a Q column calculator for calculating a column value of a unitary matrix Q by multiplying a delayed channel input with ?{square root over (norm)}; an R row calculator for receiving the delayed channel input, the output of the Q column calculator, and 1/?{square root over (norm)}, and calculating a row value of an upper triangular matrix R; a Q update calculator for receiving the delayed channel input, the output of the R row calculator, and a delayed output of the Q column calculator, and calculating a Q update matrix value; and a norm update calculator for receiving a delayed output of the norm calculator and an output of the R row calculator, and outputting a norm update matrix value.

Abstract: The present invention relates to a method for allocating a frequency domain spread code in a base station of a multi-carrier code division multiple access (MC-CDMA) communication system. A code allocation priority is established based on interference between previously allocated spread codes and a newly allocated spread code so as to minimize the interference caused by channel fading or a synchronization error according to a transmitting or receiving timing offset when a scheduler of the base station in the MC-CDMA communication system allocates a subcarrier group to the plurality of user terminals or channels, and the spread code is allocated to the plurality of user terminals or channels according to the established priority, by the scheduler of the base station.

Abstract: An apparatus for transmitting signals with multiple antennas is disclosed. The multiple antenna transmission apparatus performs space-time encoding or space-frequency encoding, and cyclically delays the encoded symbol with a plurality of delay-values to generate a plurality of delayed symbols. The multiple antenna transmission apparatus transmits the plurality of delayed symbols to the channel through a plurality of antennas. By changing the number of space areas for encoding and the number of delay-values for delaying, the number of antennas for the multiple antenna transmission apparatus is easily expanded.

Abstract: The present invention relates to a multi-input multi-output (MIMO) system for enhancing transmission performance. The MIMO system uses space-time encoding and transmit antenna selection methods, and includes a transmitter (100) and a receiver (200). The transmitter (100) includes N transmit antennas (130-1, 130-4) that are more than M tansrni antennas (130-1, 130-3) used for transmitting a signal to space channel, selects the M transmit antennas (130-1, 130-3) among the N transmit antennas (130-3 130-4), and transmits symbol by space-time encoding the symbol. The receiver (200) includes M receive antenna (120-1, 210-2) for receiving a signal from the space channel, detects an information symbol by using the signal received through the receive antenna (210-1, 210-2), generates transmit antenna selection information for selecting M transmit antennas (130-1, 130-3) among transmit antennas (i30-1, . . . 7130-4) with reference to a channel estimate, and returns the information to the transmitter.

Abstract: A device and method for estimating a carrier to interference-plus-noise ratio (CINR) in an OFDM system are provided. The CINR estimating method includes (a) receiving a preamble symbol and transmit subcarrier transmitted from a base station; (b) calculating an interference power and noise power using the preamble symbol and transmit subcarrier; (c) calculating a receive power used for the base station to transmit a preamble and data symbol; (d) estimating a preamble CINR value using an interference power, a noise power, and a receive power; (e) calculating the noise power from a subcarrier not transmitting a preamble; and (f) calculating an average CINR of data subcarriers using the preamble CINR value and the noise power.

Abstract: A space-time code used for a transmitter to transmit a plurality of data symbols to a receiver in a MIMO system, the space-time code including a code word matrix for transmitting an amount of data symbols corresponding to a product of the number of transmit antennas and a spatial multiplexing rate during one block period, wherein a row index indicates combined signals transmitted through different transmit antennas and a column index indicates time slots that correspond to the number of transmit antennas, and wherein the number of data symbols allocated to each transmit antenna in a code block corresponds to the spatial multiplexing rate, and the data symbols are combined by different combining coefficients for each transmit antenna at every time slot, and simultaneously transmitted through different transmit antennas, and each transmit antenna transmits a different set of data symbols at every time slot.

Abstract: Disclosed are a method for constructing a frame preamble in an OFDM wireless communication system, and a method for acquiring frame synchronization and searching cells using the preamble. The preamble is arranged at the beginning of a frame and constructed of a pattern repeated an integer number of times, and a CP. The pattern has a length shorter than a single OFDM symbol interval. The length of the repetitive pattern is not limited to an integer number of times a single OFDM symbol interval. Frame synchronization can be acquired by observing cross-correlation of a received signal and reference patterns and detecting the moment when the absolute value of the cross-correlation exceeds a predetermined threshold. Otherwise, frame synchronization can be acquired by observing auto-correlation of the received signal using repeated patterns included in the received signal and detecting the moment when the absolute value of the auto-correlation becomes the maximum value.

Abstract: A cell search system for a mobile station in a time division duplex system includes: a primary synchronization code search module for searching primary synchronization codes and comparing frame values of the primary synchronization codes to determine a position of the maximum value; a correlation module for estimating a phase value and acquiring a first correlation value; a secondary synchronization code search module for generating determinative variables and storing them based on the position of the maximum value; a comparison and decision module for detecting a maximum value of the determinative variables, comparing it with the values stored in the secondary synchronization code search module to count matching values, and comparing the count value with a system value to decide whether slot synchronization and group acquisition is successful; and a base station determination module for determining a second correlation value between midamble codes and the received signals, and selecting a maximum value of it

Abstract: Disclosed is a signal transmission method in a mobile communication system. Unequal error protection (UEP) ratios are determined so that the bits may have different received qualities according to the weights of the bits. The bits are repeated by a bit sequence repeater (210) according to the determined UEP ratios to generate a repeated bit sequence having a predetermined number of bits. The generated repeated bit, sequence is interleaved by an interleaver (220) and the interleaved bit sequence is symbol-mapped by a symbol-mapper (230) to generate a transmission symbol sequence, and the generated transmission symbol sequence is transmitted by the transmitter to a receiver. Furthermore, also a corresponding signal reception method, a corresponding signal transmitter and a corresponding signal receiver are disclosed.

Abstract: Disclosed is a method for allocating data and pilots, a transmitting method and device, a receiving method and device in an OFDMA system. A terminal partitions subcarrier groups and symbols from an uplink channel based on a basic pilot pattern generated by a specific reference, receives at least one subchannel based on the partitioned subcarrier groups and symbols, hops the subcarrier groups caused by the subchannel according to hopping patterns, allocates data, and differently positions the pilots per subcarrier group based on the basic pilot pattern. Accordingly, the probability of pilot collision between adjacent cells is reduced, and accuracy of channel estimation is increased through boosting the pilot subcarrier power.

Abstract: A power controlling device in a mobile communication system, and a method thereof. A base station calculates an average interference of N previous frames, and broadcasts the average interference to subscriber stations. The subscriber stations determine transmission power based on the average interference. Noise and Interference (NI) of frames within a section corresponding to a setting size is calculated (the frames may include a current frame) so an estimated interference is close to the interference generated in the frame in which the subscriber station actually transmits a signal. In addition, to more precisely estimate the NI, the NI of the current frame is compensated according to a value and is broadcast.

Abstract: The present invention relates to a transmitting apparatus of an OFDMA system and a method thereof.

Abstract: In a method for allocating transmission power in a communication system including multiple antennas, a plurality of subcarriers are grouped by a plurality of groups, and each group includes at least one subcarrier. A transmission power weight and an antenna transmission vector are calculated for each group by using channel information, a transmission power for each group of each antenna is calculated by using the transmission power weight and the antenna transmission vector for each group, and transmission signals are transmitted through the multiple antennas after determining which signals need to be transmitted from the multiple antennas by using the transmission power.

Abstract: A method for retransmitting data between two sides including a reception side and a transmission side in a mobile communication system including one or more mobile stations and one or more radio networks includes the steps of: by the reception side, storing data received from the transmission side in a first storage unit; as a result of an error-checking procedure, if the data are erroneous, requesting the transmission side to retransmit the data; by the transmission side, transmitting to the reception side a first information related to retransmission and retransmitting the requested data; by a combination unit included in the reception side, combining the retransmitted data with the data stored in the first storage unit; if the combined data are not erroneous, clearing the data and the retransmitted data from the first storage unit and transmitting the combined data to a first upper layer included in the reception side; and in response to an ACK signal from the reception side representing that normal data a

Abstract: In a handover from an asynchronous radio network to a synchronous system, long code state information and activation time are transmitted. The method of transmitting long code state information and activation time includes the step of acquiring handover-related information from a neighboring synchronous system by the asynchronous radio network. In the handover, the synchronous system transmit a first message including activation time information and long code state information to the mobile station by the asynchronous radio network and after receiving the activation time information and the long code state information, makes use of the long code state information based on the activation time information by the mobile station.