Abstract: A transmission/reception apparatus and method for performing packet retransmission considering a channel environment in a CDMA mobile communication system. Upon receiving a retransmission request from a receiver, the apparatus and method selects a modulation type to be used according to a condition of a transmission channel, and changes the previously used puncturing pattern in order to output the proper number of coded bits for the selected modulation type.

Abstract: An apparatus and a method for improving the performance of an error correction code in response to the influence of error propagation are disclosed.

Abstract: A de-rate matching method and apparatus in a High Speed Downlink Packet Access (HSDPA) system are provided.

Abstract: A method and apparatus for efficiently transmitting channel quality information on a radio channel in a mobile communication system are provided. The reporting cycle of channel quality information is changed adaptively according to time-varying characteristics associated with the Doppler frequency of a radio channel or the variation of the channel quality information. Therefore, the channel quality information is efficiently transmitted. Also, the decrease of unnecessary frequent information transmissions reduces an uplink interference power level and power consumption in user equipment (UE), as well.

Abstract: A method of transmitting/receiving channel quality information (CQI) of subcarriers in an OFDM system where data is transmitted on the subcarriers via one or more transmit antennas. The subcarriers are grouped into subcarrier groups each having at least one subcarrier and further grouped into subgroups each having one or more subgroups. A user equipment generates CQIs for one or more allocated subcarrier groups and the transmit antennas or CQIs for the allocated subcarrier groups, the subgroups of the subcarrier groups, and the transmit antennas. The group CQIs and the subgroup CQIs are transmitted to a Node B in one or more physical channel frames.

Abstract: A bit scrambling method and apparatus for packet transmission/reception in a wireless communication system are provided. A transmitter performs bit scrambling before CRC attachment and a receiver performs bit descrambling after a CRC check. This enables termination of iterative decoding at a turbo decoder according to the CRC check. Hence, power consumption is reduced and throughput is increased at a receiver.

Abstract: An apparatus and a method capable of effectively allocating sub-carriers for a plurality of users and transmitting the sub-carriers to users through multiple antennas in an orthogonal frequency division multiplexing (OFDMA) mobile communication system are provided. A sub-carrier allocation method reduces transmission power by taking a desired bit rate and power budget into consideration. The sub-carriers are optimally allocated to each antenna, so that peak to average power ratio (PARR) is reduced and Quality of Service (QoS) is improved. The apparatus and the method are adaptable for multi-users and obtain space diversity gain through multiple antennas.

Abstract: Disclosed are an apparatus and a method capable of preventing performance degradation during a channel decoding process. A bit interleaving is performed with respect to parity bits among coded bits output through a channel coding unit, thereby preventing a repetition period of the parity bits from matching a puncturing period for a rate matching. A bit de-interleaving is performed with respect to the parity bits during a channel decoding process, so that the parity bits have a repetition period identical to initial parity bits. Thus, the repetition period of the parity bits is not matched with the puncturing period for the rate matching, thereby preventing performance degradation during the channel decoding process.

Abstract: An apparatus and method for transmitting/receiving data using a multiple antenna scheme in a mobile communication system are provided. First and second code symbol sequences are generated by encoding a data symbol sequence for transmission in a predetermined encoding method. Transmission of the two code symbol sequences through the first and second transmit antennas is controlled such that if the data symbol sequence is initially transmitted, the first code symbol sequence is transmitted through the first transmit antenna and the second code symbol sequence is transmitted through the second transmit antenna and, if the data symbol sequence is retransmitted, the first code symbol sequence is transmitted through the second transmit antenna and the second code symbol sequence is transmitted through the first transmit antenna.

Abstract: Disclosed is a reception apparatus employing a post-descrambling scheme in a mobile communication system for code division multiple access and provides methods which are used for channel-compensating received multi-path signals, sorting the channel-compensation signals according to positions in time in consideration of multi-path latency, combining the sorted signals, and descrambling each of the combined signals by means of one of preset scrambling codes in a reception apparatus of Code Division Multiple Access (CDMA) mobile communication system.

Abstract: A method and system of retransmitting uplink packet data from a user equipment (UE) in a handover region to Node Bs. The UE transmits packet data to the Node Bs on an enhanced uplink dedicated transport channel (EUDCH). The Node Bs transmit to the UE first response fields indicating whether the Node Bs have received good packet data or bad packet data, and second response fields that the Node Bs received from an RNC indicating whether a radio network controller (RNC) has received good packet data or bad packet data. The UE then detects the first and second response fields and retransmits the uplink packet data according to the values of the response fields in the UE.

Abstract: An interleaver separates an area of a buffer included therein into a first write area and a second write area according to a ratio of coded bits with higher priority to coded bits with lower priority, sequentially writes a stream of the coded bits with higher priority in a row direction from a first column to a last column among the columns in the first write area, and sequentially writes a stream of the coded bits with lower priority in a row direction from a first column to a last column among the columns in the second write area, and permutes the columns in the buffer area according to a given rule.

Abstract: A transmission/reception apparatus and method for performing packet retransmission considering a channel environment in a CDMA mobile communication system. Upon receiving a retransmission request from a receiver, the apparatus and method selects a modulation type to be used according to a condition of a transmission channel, and changes the previously used puncturing pattern in order to output the proper number of coded bits for the selected modulation type.

Abstract: A transmitting/receiving apparatus and method for packet retransmission in a mobile communication system. Upon request for a retransmission from a receiver, a transmitter generates first coded bits by inverting initially transmitted coded bits, generates second coded bits by separating the initially transmitted coded bits into a first bit group having a relatively high priority and a second bit group having a relatively low priority and exchanging the first bit group with the second bit group, and generates third coded bits by inverting the exchanged coded bits. The transmitter selects one of the first coded bits, the second coded bits according to the sequence number of a retransmission request received from the receiver, and the third coded bits and maps the selected coded bits to modulation symbols. The transmitter then transmits the modulation symbols to the receiver.

Abstract: An apparatus for retransmitting data at a retransmission request from a receiver by a transmitter in a CDMA mobile communication system including a turbo encoder with a given coding rate and initially transmitting systematic bits and parity bits obtained by encoding the data by the turbo encoder using one modulation mode among a plurality of modulation modes. A controller determines a modulation mode to be used between the transmitter and the receiver in response to the retransmission request. A distributor distributes coded bits obtained by encoding the data at the coding rate into systematic bits and parity bits. A selector selects coded bits transmittable by the determined modulation mode among the systematic bits and the parity bits at the initial transmission, if the determined modulation mode is different from the modulation mode used at initial transmission. A modulator modulates the transmittable coded bits into modulated symbols according to the determined modulation mode.

Abstract: A device for linearizing a transmitter in a digital radio communication system. In the device, a predistortion lookup table stores predistortion data determined by measuring in advance distortion characteristics of the transmitter with respect to input baseband data. During transmission, the device synthesizes the input baseband data with the predistortion data to predistort the input data so as to compensate for the distortion characteristics caused by non-linear elements constituting the transmitter.

Abstract: A digital receiver with a polyphase structure extracts specific channel data from multi-channel discrete time data. An input signal is sequentially delayed by a plurality of delays connected in series. The input signal and each sequentially delayed signal are processed by two down-samplers, for lowering the sampling rate, and two filters, for filtering for a desired channel of the input signal. Each down-sampler is connected in series with one filter. Also included are two pluralities of adders, the number of adders of each plurality is equal, and each of the adders of each plurality is connected in series. The number of adders is equal to two times the number of delays. The adders recombine the outputs of the filters (or down-samplers, depending on the order of the series connection), each adder recombining two filter outputs. The order that the adders recombine the signal coincides with the order that the signal was delayed.

Abstract: A decimation filtering apparatus using interpolated second order polynomials compensates for a droop caused by a CIC (Cascaded Integrator-Comb) filter. The decimation filter includes a CIC decimation filter for decimation filtering the sampling signal to downconvert a sampling signal; an ISOP filter for monotonically increasing an output of the CIC decimation filter to compensate for a passband droop caused by the CIC decimation filter; a multistage halfband filter including at least one modified halfband filter for half-decimating a signal output from the ISOP filter, thereby downconverting the ISOP filter output signal; and a programmable FIR filter that compensates for a passband droop of a signal output from the multistage halfband filter.