Abstract: The present invention relates to an apparatus and method for detecting a data rate in a turbo decoder for a mobile communication system. When a rate selector selects one data rate among a plurality of data rates, a turbo decoder repeatedly decodes an input data frame within a predetermined repetition limit number using the selected data rate and outputs the decoded data. A CRC detector performs CRC check on the decoded data and outputs the CRC check result, and a decoding state measurer measures decoding quality depending on the decoded data and outputs decoding state information. A controller then sets the repetition limit number to a predetermined minimum value, controls the repetition limit number according to the decoding state information, controls the rate selector and determines a data rate of the input data depending on the CRC check result.

Abstract: A method and apparatus for mapping a stream of bits output from an encoder to a stream of bits for 2m-ary modulation. The method and apparatus divides the stream of bits from the encoder into a first period and a second period. The first period includes bits with higher priority in the stream of the bits output from the encoder, and the second period includes bits with lower priority. The method and apparatus maps the bits existing in the first period to bit positions with higher reliability in a stream of m bits representing each of the bits for 2m-ary modulation, and maps the bits existing in the second period to bit positions with lower reliability in the stream of m bits.

Abstract: A device and method for rate matching channel-encoded symbols in a data communication system. The rate matching device and method can be applied to a data communication system which uses one or both of a non-systematic code (such as a convolutional code or a linear block code) and a systematic code (such as a turbo code). In one aspect, the rate matching device includes a plurality of rate matching blocks, the number of the rate matching blocks being equal to a reciprocal of a coding rate of a channel encoder. The rate matching device can rate match the symbols encoded with a non-systematic code or the symbols encoded with a systematic code, by changing initial parameters including the number of input symbols, the number of output symbols, and the puncturing or repetition pattern determining parameters.

Abstract: A Hybrid Automatic Repeat reQuest (HARQ) control apparatus and method for detecting a message received over a packet data control channel in a mobile communication system are provided in which a base station transmits a packet data control message over at least one packet data control channel and transmits packet data to a mobile station over a packet data channel. A control channel decoder decodes a control message received over the packet data control channel. Based on the decoded control message, the HARQ controller determines at least one of whether to perform demodulation and decoding on a packet received over the packet data channel, whether to update a Walsh mask, and whether to perform state transition on the mobile station. The HARQ controller based on the determination performs at least one of the following functions: outputs demodulation and decoding parameters, updates a Walsh mask, and outputs a state transition value to an upper layer.

Abstract: An apparatus and method for generating an encoding matrix for a low density parity check (LDPC) code having a dual-diagonal matrix as a parity check matrix are disclosed. The apparatus and method construct an information sub-matrix of the encoding matrix with a predetermined number of square matrixes according to a predetermined code rate such that each of the square matrixes has columns and rows with a weight of 1 and has a different offset value, combine the square matrixes with the dual-diagonal matrix, and perform inter-row permutation on the information sub-matrix.

Abstract: A mobile station apparatus and method provide for receiving packet data transmitted over a packet data channel, decoding the received packet data and delivering the decoded packet data to an upper layer in a mobile communication system transmitting packet data transmitted over a forward packet data channel and transmitting, over a forward packet data control channel, demodulation and decoding information of packet data transmitted over the forward packet data channel. The apparatus and method comprise a fast turbo decoder for decoding packet data received over the packet data channel depending on information received over the forward packet data control channel, storing the decoded data, and outputting buffer information of the stored data; an output buffer for storing the received packet data, and outputting the packet data upon receiving a read request.

Abstract: A data rate detecting device detects a data rate for a received signal based on a variation of the energy for the respective received signals between the two adjacent intervals upon failure to receive information about the data rate, and performs channel decoding of the detected data rate information. First, the data rate detecting device divides an interval defined as between a lowest and highest one of a plurality of given data rates into m discriminating intervals. Then, the device calculates a difference between an average energy of received signals up to an i'th discriminating interval and an average energy of received signals for an (i+1)'th discriminating interval, wherein i is an integer is less than m. If the difference between the average energies is greater than or equal to a threshold value, the device determines that the received signal in the (i+1)'th discriminating interval is transmitted at a data rate corresponding to the i'th discriminating interval.

Abstract: A P-BRO interleaver and a method for optimizing parameters according to an interleaver size for the P-BRO interleaver. The P-BRO interleaver sequentially, by columns, arranges an input data stream of size N in a matrix having 2m rows and (J−1) columns, and R rows in a Jth column, P-BRO interleaves the arranged data, and reads the interleaved data by rows.

Abstract: An Forward Error Correction (FEC) apparatus and method for reducing Bit error rates (BER) and Frame Error Rates (FER) using turbo decoding in a digital communication system. In a constituent decoder for decoding a turbo code, a first adder calculates the LLR of a received code symbol by calculating the difference between the probability of the code symbol being 1 and that of the code symbol being 0 at an arbitrary state of a turbo decoding trellis. A second adder adds the transmission information and a priori information of the code symbol. A third adder calculates the difference between the outputs of the first and second adders as extrinsic information. A first multiplier multiplies the output of the third adder by a predetermined weighting factor as a feedback gain. A correction value calculator calculates a correction value using the difference between the best metric and the second best metric of the code symbol. A fourth adder adds the correction value to the output of the first multiplier.

Abstract: An FEC apparatus and method is provided that uses turbo codes. An input frame is iteratively decoded until an iterative decoding stop command is received under a predetermined control, and the absolute reliability of each symbol in the frame is output. The minimum of the absolute reliabilities is detected as a measurement, and a threshold is detected using the a-priori information and extrinsic information of the each symbol. The measurement is compared with the threshold, and the iterative decoding stop command is output according to the comparison result.

Abstract: A device for sequentially storing input bit symbols of a given interleaver size N in a memory at an address from 1 to N 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)+BRO(K/J), where K (0≦K≦(N−1)) denotes a reading sequence and BRO is a function for converting a binary value to a decimal value by bit reversing.

Abstract: An apparatus and method for reading written symbols by deinterleaving to decode a written encoder packet in a receiver for a mobile communication system supporting turbo coding and interleaving, such that a turbo-coded/interleaved encoder packet has a bit shift value m, an up-limit value J and a remainder R, and a stream of symbols of the encoder packet is written in order of column to row. The apparatus and method perform the operations of generating an interim address by bit reversal order (BRO) assuming that the remainder R is 0 for the received symbols; calculating an address compensation factor for compensating the interim address in consideration of a column formed with the remainder; and generating a read address by adding the interim address and the address compensation factor for a decoding-required symbol, and reading a symbol written in the generated read address.

Abstract: A method and apparatus for effectively controlling data input to a turbo decoder for decoding forward packet data traffic in a 1xEV-DV mobile station (MS) are disclosed. After received code symbols are stored in one of several memories and read in deinterleaving order, read addresses and chip select signals are generated for the memories based on encoder packet size in synchronization to a decoder clock signal. The decoding starts by inputting a predetermined number of code symbols to the turbo decoder in an appropriate order. The decoder input apparatus reads demodulated forward packet data from decoder input buffers in an appropriate order using the read addresses and chip select signals to generate turbo decoder input data in an appropriate form. Thus, a small-size, low-cost, low-power consumption MS is achieved by processing channel-interleaved data at high speed and with reduced process delay and providing them to a decoder.

Abstract: A device and method for rate matching channel-encoded symbols in a data communication system. The rate matching device and method can be applied to a data communication system which uses one or both of a non-systematic code (such as a convolutional code or a linear block code) and a systematic code (such as a turbo code). In one aspect, the rate matching device includes a plurality of rate matching blocks, the number of the rate matching blocks being equal to a reciprocal of a coding rate of a channel encoder. The rate matching device can rate match the symbols encoded with a non-systematic code or the symbols encoded with a systematic code, by changing initial parameters including the number of input symbols, the number of output symbols, and the puncturing or repetition pattern determining parameters.

Abstract: An adaptive MAP channel decoding apparatus and method in a mobile communication system. In the adaptive MAP channel decoding apparatus, a channel estimator calculates channel noise power and a scaling factor, a controller determines an operation mode by checking accumulated channel noise power and the scaling factor, and a MAP channel decoder performs a MAP decoding operation with an E function including a log function in a static channel mode and an E function free of a log function in a time-varying channel mode.

Abstract: A method for controlling a turbo decoding time in a high-speed packet data communication system. In a mobile communication system which receives a control message from a packet data control channel, at the same time receives packet data from the packet data channel, performs demodulating and turbo-decoding of the packet data during a predetermined response (ACK/NAK) time delay using a demodulation result of the packet data control channel, creates a result of the turbo decoding in the form of a response (ACK/NAK) signal, and transmits the turbo decoding result, the method includes the steps of a) demodulating the control message when simultaneously receiving the control message and the packet data, and demodulating and decoding the packet data, and b) if the response time delay expires while decoding the packet data, interrupting a decoding operation of the turbo decoder.

Abstract: An apparatus for controlling a Hybrid Automatic Repeat Request (HARQ) is provided. In the apparatus, a physical layer includes a decoder for decoding a control message received over the packet data control channel, a demodulator for demodulating packet data received over the packet data channel, and a turbo decoder for decoding the demodulated packet data. A physical layer's HARQ controller determines whether to demodulate and decode the received packet data depending on a decoding result of the control message, outputs the decoded control message to the demodulator and the turbo decoder for demodulation and decoding of the received packet data, controls output of a response signal according to decoding result of the packet data, and delivers the turbo-decoded packet data to an upper layer.

Abstract: A device for generating L addresses, which are smaller in number than 2m×Ng virtual addresses, for reading data from an interleaver memory in which L data bits are stored, the device including: Ng PN generators each including m memories; an address generator for adding an offset value to the input data size to provide a virtual address having a size of a multiple of 2m, and generating addresses other than addresses corresponding to the offset value in address generation areas using the address generation areas having the size of 2m; and means for reading the input data from the interleaver memory using the addresses generated from the address generation areas.

Abstract: A QCTC (Quasi-Complementary Turbo Code) generating apparatus having a turbo encoder for generating an information symbol sequence and a plurality of parity symbol sequences by encoding the information symbol sequence; a channel interleaver for individually interleaving the symbol sequences, generating new parity symbol sequences by multiplexing the symbols of parity symbol sequences with the same priority levels, and serially concatenating the information symbol sequence and the new parity symbol sequences; and a QCTC generator for generating a sub-code with a given code rate by recursively selecting a predetermined number of symbols from the concatenated symbol sequence at a given starting position.

Abstract: A method and apparatus for deshuffling received shuffled data in a communication system supporting multi-level modulation. A transmitter encodes information bits and shuffles code symbols so that systematic symbols having a relatively high priority are disposed at high-transmission reliability positions and parity symbols having a relatively low priority are disposed at low-transmission reliability positions in a modulation symbol. A receiver demodulates received data and outputs a modulation symbol having a plurality of code symbols, stores the code symbols separately as systematic symbols and parity symbols in corresponding memory areas according to a deshuffling order corresponding to the shuffling, reads the stored code symbols, decodes the stored code symbols at a predetermined code rate, and thus outputs an packet.