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: 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: 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 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 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: 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: Disclosed is an apparatus and method for supporting automatic repeat request (ARQ) in a high-speed wireless packet data communication system. A mobile station receives control information including a subpacket identifier (SP_ID) representing the sequence of a subpacket, the size of an encoder packet (EP_SIZE), and a sequence identifier (AI_SN) that is toggled each time a new encoder packet is transmitted, while receiving one of a plurality of subpackets generated by segmenting a bit stream acquired by encoding a transmission encoder packet. The mobile station determines whether it will perform a decoding process caused by initial transmission or a decoding process caused by retransmission on the received subpacket, based on the control information.

Abstract: There is provided a device and method for transmitting packet data in a mobile communication system. A sub-code generator generates a plurality of sub-codes with the same or different code rates for the input of a PLP (Physical Layer Packet) information bit stream. A controller determines a minimum data rate by which the number of the modulation symbols of a sub-code generated by a predetermined modulation method is equal to or greater than the number of transmittable modulation symbols for each time period. A symbol pruner prunes part of the modulation symbols of the sub-code to make the number of the modulation symbols of the sub-code equal to the number of transmittable modulation symbols for the time period, if the number of the modulation symbols of the sub-code is greater than the number of transmittable modulation symbols for the time period.

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.

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: An apparatus and method for soft-combining demodulated symbols in a mobile communication system. In the mobile communication system, a transmitting apparatus modulates symbols in different modulation schemes and a receiving apparatus demodulates the modulation symbols in correspondence with the modulation schemes. The soft symbol combining apparatus includes an RWF calculator, an RWF controller, and a soft symbol controller. The RWF calculator calculates an energy of a modulation symbol from each of the modulation schemes and determines relative ratios of the energies to be RWFs for the modulation schemes. The RWF controller multiplies soft metrics of the demodulated soft symbols by the RWFs. Finally, the soft symbol controller combines the multiplied soft metrics.

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: There is provided a method for encoding input information bits by a quasi-complementary turbo code (QCTC) at a predetermined code rate to generate codeword symbols and transmitting the generated codeword symbols. The method comprises selecting one pattern among predetermined patterns corresponding to at least one of the generated codeword symbols in order to transmit the generated codeword symbols by a sub-packet length determined according to a data rate; reading information corresponding to the data rate, the sub-packet length and the selected pattern from a table in which identification information indicating the data rate, the sub-packet length and the selected pattern is previously mapped to given information; and transmitting the generated codeword symbols according to the read information and the selected pattern.

Abstract: An apparatus and method for determining an optimum modulation scheme and code rate in a communication system using a variable transmission scheme. In a transmitter included in the communication system, an encoder encodes an encoder packet (EP) and a plurality of modulators having different modulation orders modulate sub-packets being codewords output from the encoder. A selector selects one of the modulators by comparing an MPR (Modulation order Product code Rate) being a ratio of an EP size to a number of payload modulation symbols, and comparing the MPR with a threshold.

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: 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: An apparatus generates quasi-complementary turbo codes in a communication system. The apparatus includes a turbo encoder, an interleaver for interleaving symbols output from the turbo encoder according to a given rule, and a code generator for generating the quasi-complementary turbo codes by puncturing and repeating the interleaved symbols from the interleaver. Further, an apparatus decodes quasi-complementary turbo codes in the communication system. The decoding apparatus includes a code decoder for generating code symbols according to a code rate transmitted through depuncturing sub-codes of quasi-complementary turbo codes transmitted from a transmitter and soft combining the sub-codes, a deinterleaver for deinterleaving the symbols output from the code decoder, and a turbo decoder for decoding an output of the deinterleaver.

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: A method and apparatus for determining an optimum modulation scheme for a retransmission in a communication system supporting HARQ. When two modulation schemes are available, at an initial transmission, information is modulated in the lower-order modulation scheme if a first MPR is less than a first threshold, and in the higher-order modulation scheme if the first MPR is greater than or equal to the first threshold. Here, an MPR is determined by an EP size, the number of available Walsh codes, and the number of slots per sub-packet that are used for a transmission. To select one of the modulation schemes for a retransmission, a second MPR is calculated using an EP size, the number of available Walsh codes, and the number of slots per sub-packet that are used for the retransmission. If the first MPR is equal to or less than a second threshold greater than the first threshold, the lower-order modulation scheme is selected.

Abstract: Disclosed is provided 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.