Abstract: A method and apparatus for transmitting an orthogonal frequency division multiplexing (OFDM) symbol from a base station to a mobile station in a wireless mobile communication system with a multicell/multisector structure formed by a plurality of base stations. The base station receives a plurality of complex symbols to be transmitted to the mobile station. The base station performs space-time coding (STC) on the plurality of complex symbols and selects the STC-coded symbols such that different space-time code streams are transmitted to adjacent sectors among sectors formed by the base station and other base stations. In addition, a selection pattern of the space-time code streams is updated such that it is circulated every predetermined time period, thereby providing uniform sector diversity for all mobile stations located in a sector/cell boundary.

Abstract: A method and apparatus for decoding inner and/or outer codes in a mobile communication system. The inner and/or outer codes are decoded at low power and high speed. An inner decoder performs channel decoding and cyclic redundancy checking (CRC) on symbols received through a wireless network. An outer decoder performs outer coding on the received symbols. An erasure symbol identifier outputs information of erasure symbols in which a reception error has occurred. The reception error is determined from a result of the CRC on the received symbols. A controller counts the number of received symbols and the number of erasure symbols, and stops an operation of at least one of the inner and outer decoders when at least one of the number of received symbols and the number of erasure symbols is equal to a preset reference value.

Abstract: An apparatus and method for decoding low density parity check (LDPC) codes are provided. A memory module configured by a plurality of unit memories stores a reliability value. Variable node processors perform a computation associated with a variable node, and update data of the memory module in a column direction, respectively. Check node processors perform a computation associated with a check node, and update data of the memory module in a row direction, respectively. A parity checker determines if all errors have been corrected such that an iterative decoding process is performed. A memory access control module selects a unit memory to be updated by a variable node processor or a check node processor.

Abstract: A method and apparatus for transmitting and receiving a broadcast service in a mobile communication system which outer-codes frames for a plurality of broadcast services and Time Domain Multiplex (TDM)-transmits the outer-coded frames. A transmitter transmits a broadcast parameter message comprising information indicating a specific sub-buffer in which respective broadcast services are stored. A receiver for receiving the broadcast parameter message from the transmitter, and maps the sub-buffer to a corresponding sub-block mask based on the broadcast parameter message. The transmitter TDM-transmits the frames for the plurality of broadcast services per sub-block. The receiver selectively receives frames for a desired broadcast service using the sub-block mask and decodes the selectively received frames.

Abstract: A method and apparatus for determining the rate of data transmitted at variable rates. In the method and apparatus, received data is pre-decoded at receivable rates by pre-decoders which adopt a simple structure and perform pre-decoding rapidly, quality information of the pre-decoded data is detected, and the rate of the received data is estimated based on the quality information of the pre-decoded data. Therefore, the decoding speed of the received data and the decision speed of the data rate increase, reducing power consumption.

Abstract: There is provided an apparatus and method of generating two-dimensional QCTCs. The sub-code sets of QCTCs with given code rates are generated and the sub-codes are rearranged in a sub-code set with a different code rate, for use in the next transmission to a sub-code with a predetermined code rate.

Abstract: A method and apparatus are provided for transmitting and receiving pilot signals to estimate link gains and channels of neighboring base stations in an orthogonal frequency division multiple access (OFDMA) system. Each base station cyclically shifts a frequency domain signal of the same pseudo random (PN) code by a predetermined multiple of a time interval between pilots. A mobile terminal cyclically shifts a time domain pilot signal by a time interval between pilots associated with a base station with which the mobile terminal currently communicates in a reverse direction of cyclic shift of the base station, and estimates a channel and a link gain of the base station.

Abstract: An apparatus and method for determining a modulation order of packet data to be transmitted through a subcarrier in a transmission apparatus. In the apparatus and method, transmitter physical channels encode and modulate data to transmit the user data with OFDM symbols. A controller outputs packet data to the transmitter physical channels, and determines the number of transmission slots, the number of OFDM symbols, the number of subchannels, and a size of an encoder packet. A modulation order and code rate decider receives, from the controller, the number of transmission slots, the number of OFDM symbols, the number of subchannels, and a size of an encoder packet, calculates a Modulation order Product code Rate (MPR), determines a modulation order according to the MPR, and outputs the determined modulation order to a corresponding physical channel.

Abstract: An apparatus for generating Quasi-Complementary Duo-Binary Turbo Codes (QC-DBTC). The apparatus includes a QC-DBTC encoder which receives an information symbol stream and generates a plurality of systematic symbol streams and a plurality of parity symbol streams according to a given code rate. The apparatus further includes a quad-symbol mapper which quad-maps the systematic symbol streams to one symbol stream, a channel interleaver which independently interleaves the quad-mapped systematic symbol stream and the parity symbol streams, quad-demaps the quad-mapped systematic symbol stream, interlaces symbols in parity symbol streams, and serial-concatenates the quad-demapped systematic symbol stream to the interlaced parity symbol streams. A duo-binary turbo code generator is further provided to repeat the serial-concatenated symbol stream, and select a predetermined number of symbols from the repeated symbol stream according to a code rate and selection information, thereby generating QC-DBTC codes.

Abstract: Disclosed is a method for normalizing metric values in a decoder which uses a plurality of metric values of a next state in a state transition period having a present state and the next state, each metric value having a survival path metric value having a value equal to or higher than a competition path metric value. The method comprises detecting the survival path metric values out of the metric values; detecting a minimum survival path metric value out of the detected survival path metric values; determining whether the detected minimum survival path metric value exceeds a threshold value; and subtracting, when the minimum survival path metric value exceeds the threshold value, a given normalization value from the metric values, to output normalized metric values.

Abstract: A forward packet data control channel (F-PDCCH) receiver for reducing alarms relating to errors in a packet data control channel for transmitting a control signal in a mobile communication system and a method of using the same. In the F-PDCCH receiver, a decoding part decodes received symbols and calculates an information word and an absolute value of a difference between two path metrics. A false alarm reduction function compares the absolute value received from the decoding part with a predetermined threshold, and outputs a decoding value indicating whether an alarm is generated according to the comparison result. A blind slot format detector detects a blind slot format based on the absolute value received from the decoding part.

Abstract: An interleaving apparatus and method for a communication system which can be applied to determine a new interleaver size N?=2m×(j+1) and addresses of 0 to N??1, if a given interleaver size N is larger than 2m×j and smaller than 2m×(j+1), where m represents a first parameter indicating a number of consecutive zero bits from a least significant bit (LSB) to a most significant bit (MSB), and j represents a second parameter corresponding to a decimal value other than said consecutive zero bits. The interleaving apparatus and method sequentially stores N input data bits in an interleaver memory with the new interleaver size N? from an address 0 to an address N?1. The interleaving apparatus and method then executes a Partial Bit Reversal(PBRO)-interleaving the memory with the new interleaver size N?, and reads data from the memory by deleting addresses corresponding to addresses of N to N??1 of the memory before interleaving.

Abstract: Disclosed is a transmission/reception apparatus and method for providing compatibility between Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing (OFDM) in a forward link. The proposed transmission/reception apparatus and method uses a traffic channel based on OFDM while using a pilot channel and a sync channel used in the CDMA scheme. Thus, a transmitter adds a pilot channel signal and a sync channel signal to OFDM-modulated symbols before transmission, and a receiver acquires a pilot channel signal and a sync channel signal, and removes them from a received signal, thereby outputting only pure OFDM-modulated symbols.

Abstract: A transmitting device including an encoder for receiving an information bit stream in a frame and outputting an information symbol, a first parity symbol, and a second parity symbol by encoding each information bit. An interleaver sequentially arranges the information symbols and the first and second parity symbols by rows in an array with an integer number of rows and an integer number of columns. The interleaver further outputs a plurality of radio frames in a stream, by reading the symbols by going down each column, starting at the leftmost column and proceeding right. Each radio frame has a predetermined size. A demultiplexer demultiplexes the radio frames received from the interleaver into streams of information, first parity symbols, and second parity symbols. A rate matcher bypasses the stream of information symbols and punctures the streams of the first and second parity symbols for rate matching.

Abstract: Disclosed is an apparatus for stopping iterative decoding in a turbo decoder performing iterative decoding on a received frame comprised of information bits and then outputting the iteratively decoded results. A turbo decoder sequentially outputs absolute LLR (Log Likelihood Ratio) values associated with the respective information bits of the received frame by the iterative decoding, and stops the iterative decoding in response to a stop command for the iterative decoding. A minimum LLR detector selects a minimum value M(i) among the sequentially output absolute LLR values. A controller issues a command to stop the iterative decoding, if the minimum value M(i) is larger than a first threshold determined based on a minimum value Fmin among absolute LLR values output through previous iterative decoding.

Abstract: An apparatus and method for transmitting Walsh information over a packet data control channel in a base station of a mobile communication system that transmits packet data and has the packet data control channel for transmitting control information related to transmission of packet data. Receivers decode reverse ACK channel (R-ACKCH) signals received from corresponding mobile stations, and count the number of NAKs from the decoded information. A Walsh mask broadcasting controller receives the number of NAKs from the receivers, and outputs a Walsh mask information broadcasting enable signal if the number of NAKs is larger than a predetermined threshold. A transmitter generates and broadcasts Walsh mask information of the base station upon receiving the Walsh mask information broadcasting enable signal.

Abstract: An apparatus and method for receiving a packet data control channel in a mobile communication system that transmits packet data and has the packet data control channel for transmitting control information related to transmission of packet data are provided. A receiver receives and despreads a signal on the packet data channel and a signal on the packet data control channel, separately outputs the signals, and estimates a noise of a received signal. A signal level detector receives a noise estimation value and samples of the packet data control channel signal from the receiver, and outputs a validity signal for detecting whether information is received over the packet data control channel. A packet data control channel decoder decodes the packet data control channel signal if the validity signal received from the signal level detector is valid.

Abstract: An apparatus for receiving data through channels in a communication system including a first channel for transmitting control information related to a second channel and the second channel for transmitting packet data, the apparatus comprising: a first channel decoder for decoding the first channel and outputting control information; an active Walsh mask storing section for storing a Walsh mask acquired from the control information; a second channel decoder for decoding the second channel using the Walsh mask stored in the active Walsh mask storing section and outputting a decoding result; and a control unit for changing the Walsh mask to a previous Walsh mask if a Walsh mask error is determined according the decoding result.

Abstract: A quantization method for an iterative decoder. In the quantization method, received signal levels are equally divided into predetermined intervals within a range 2n (n is a positive integer) times greater than the transmission signal level range of the transmitter, and the level of the input signal received in each period is quantized.

Abstract: A device for sequentially storing input bit symbols of a given interleaver size N in a memory at an address from 0 to N-1 and reading the stored bit symbols from the memory. The device comprises a look-up table for providing a first variable m and a second variable J satisfying the equation N=2m×J; and an address generator for generating a read address depending on the first and second variables m and J provided from the look-up table. The read address is determined by 2m(K mod J)+BROm(K/J), where K (0?K?(N-1)) denotes a reading sequence, BROm(y) is the bit-reversed m-bit value of y and/is a function in which a quotient of K divided by d is obtained, the quotient being an integer.