Abstract: Disclosed is an apparatus for encoding TFCI bits in an asynchronous CDMA mobile communication system including a UE and a Node B for transmitting packet data to the UE. A TFCI bit generator creates the TFCI bits, the number of which is variable depending on an information bit ratio of the first channel to the second channel. A code length information generator generates code length information for setting a length of a codeword according to the information bit ratio. A Walsh code generator generates first to fifth basis Walsh codewords. A sequence generator generates an all-1 sequence. A mask generator generates first to fourth basis masks. First to tenth multipliers multiply the TFCI bits by the first to fifth basis Walsh codewords, the all-1 sequence and the first to fourth basis masks, respectively. An adder adds outputs of the first to tenth multipliers. A puncturer punctures a codeword output from the adder according to the code length information.

Abstract: A device and method for generating and distributing convolutional codes such that performance degradation due to a bad link environment may be minimized during channel decoding in a CDMA communication system. The convolutional encoder encodes transmission data at a coding rate of R=1/6 and can be used for a channel encoder. Such a channel encoder can be used in both a DS-CDMA communication system and a multicarrier CDMA communication system. When the channel encoder is used in the multicarrier CDMA communication system, the symbols outputted from multiple constituent encoders for the channel encoder are distributed to multiple carrier channels according to a predetermined rule, and the constituent encoders for the channel encoder can minimize the performance degradation of the overall channel encoder even though an output of a particular constituent encoder is completely off at the transmission channel.

Abstract: A device for generating quasi-orthogonal codes which allow the minimum interference with orthogonal codes in a mobile communication system using the orthogonal codes. The device includes a first spreader for spreading at least one input signal with quasi-orthogonal codes, a second spreader for spreading another input signal with Walsh codes, and a PN (Pseudo-Noise) spreader for complex-spreading output signals of the first and second spreaders with PN sequences. The quasi-orthogonal codes are characterized in that a partial correlation value with the Walsh codes does not exceed a lowest partial correlation limit value.

Abstract: A code set generating method in a mobile communications system having Nf frequency channels and Np phase channels. In the method, a code length Nc is obtained by Nf×Np, a minimum distance Nd between codewords in a code set and frequency diversity Nfd are determined, code sets are detected according to Nc, Nd, and Nfd, a code set is selected, which shows such a Hamming distance distribution among code words that minimizes demodulation errors from the detected code sets, and the code set is stored in a mapping table of a demodulator.