Abstract: Disclosed is an apparatus and a method for effectively allocating frequency resources in a mobile communication system. The method includes: determining a first offset of a preset frequency band from among all frequency bands, determining a second offset corresponding to a symbol unit in the preset frequency band, and allocating frequency resources to data, the frequency resources corresponding to a sum of the first offset and the second offset.

Abstract: Disclosed is an apparatus and method for generating a QCTC (Quasi-Complementary Turbo Code) considering a characteristic of a turbo code in a packet communication system or a communication system using an ARQ (Automatic Repeat reQuest) scheme by segmenting a length N of the QCTC into a predetermined number of sections, determining SPIDs (Sub-code Packet Identifications) corresponding to the segmented sections, and specifying one of the SPIDs allocated for initial transmission of the sub-code; calculating a number of remaining symbols represented by N-Fs, where N is a length of the QCTC and Fs is a starting symbol position of the sub-code of the QCTC; determining a last symbol position Ls of the sub-code by comparing the number of the remaining symbols with a length of the sub-code; and sequentially transmitting symbols of the sub-code from the starting symbol position Fs to the last symbol position Ls.

Abstract: An 8-ary PSK demodulation apparatus for receiving an input signal Rk(Xk, Yk) comprised of a kth quadrature-phase component Yk and a kth in-phase component Xk, and for generating soft decision values ?(sk,0), ?(sk,1), and ?(sk,2) for the input signal Rk(Xk, Yk) by a soft decision means. A calculator calculates Zk by subtracting a level |Yk| of the quadrature-phase signal component Yk from a level |Xk| of the in-phase signal component Xk, and outputs the Zk as a first soft decision value. A first selector selects the Zk or reverse ?Zk, according to an MSB of the quadrature-phase signal component Yk. A second selector selects the Zk or the reverse ?Zk according to an MSB of the in-phase signal component Xk. A third selector selects an output of the second selector or a value “0” according to an MSB of the Zk. A first adder adds ?{square root over (2)}Yk to an output of the third selector, and outputs the result value as a third soft decision value.

Abstract: A 64-ary QAM (Quadrature Amplitude Modulation) demodulation apparatus and method for receiving an input signal Rk(Xk,Yk) comprised of a kth quadrature-phase signal Yk and a kth in-phase signal Xk, and generating soft decision values ?(sk,5), ?(sk,4), ?(sk,3), ?(sk,2), ?(sk,1) and ?(sk,0) for the input signal Rk(Xk, Yk) are disclosed. A first soft decision value generator receives the quadrature-phase signal Yk of the received signal Rk and a distance value 2a between six demodulated symbols on the same axis, and generates soft decision values ?(sk,5), ?(sk,4) and ?(sk,3) for sixth, fifth, and fourth demodulated symbols. A second soft decision value generator receives the in-phase signal Xk of the received signal Rk and the distance value 2a between the six demodulated symbols on the same axis, and generates soft decision values ?(sk,2), ?(sk,1) and ?(sk,0) for third, second and first demodulated symbol.

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: 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 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: 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 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: 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: 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 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: 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 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 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 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.