Abstract: If a spreading factor is small, the number of multiple paths is large, and an interference signal power is larger than a desired signal power, a conventional RAKE combining receiver presents insufficient suppression of the interference signal by means of despreading, resulting in largely degraded reception performances.

Abstract: Analog processing sections (3a to 3b) generate base band analog signal from the received signal. A/D converting sections (4a to 4b) the outputs of the analog processing sections into digital signals. Soft-decision output equalizers (11a to 11b) make soft decisions on the digital signals. A combining section (12) combines the results of the soft decisions to output a soft-decision value. An error correcting section (13) performs error correction processing with respect to the soft-decision value.

Abstract: A receiver receives a signal that has been encoded, interleaved, burst mapping processed, and modulated via a wireless channel. The receiver judges a modulation scheme for a burst based on a part of a known sequence in the burst; calculates a soft decision value for the burst based on the judged modulation scheme; and changes the soft decision value, if the judged modulation scheme is determined to be incorrect.

Abstract: A frequency offset correction value estimation section (21) receives a signal including a predetermined fixed pattern from a transmission side, thereafter, selects a combination of fixed patterns used in a process of estimating a frequency offset is selected depending on the state of a channel, and an estimation result of the frequency offset calculated by the combination of the fixed patterns is output as a correction value of a determined frequency offset. A frequency offset correction section (22) receives the received signal obtained after the correction is performed for correcting a frequency offset of the received signal on the basis of the correction value, and an equalizer (23) demodulates the received signal by using a predetermined algorithm.

Abstract: A modulation scheme judging section (61) judges a modulation scheme for each burst based on a part of known sequence in a received signal, a soft decision section (62) gives a soft decision on the received signal, based on the judged modulation scheme, a soft decision value alteration controller (63) provides control, if there is a wrong judgement in the judgement of a past modulation scheme made during a period in which there has been no change in the modulation scheme, for correcting a corresponding soft decision value, a soft decision value storage (64) stores the soft decision value output by the soft decision section, and corrects the soft decision value under the control of the soft decision value alteration controller (63), a deinterleaver (16) performs a deinterleaving process to the stored soft decision value, and a decoder (17) decodes the soft decision value as after the deinterleaving process.

Abstract: Analog processing sections (3a to 3b) generate base band analog signal from the received signal. A/D converting sections (4a to 4b) the outputs of the analog processing sections into digital signals. Soft-decision output equalizers (11a to 11b) make soft decisions on the digital signals. A combining section (12) combines the results of the soft decisions to output a soft-decision value. An error correcting section (13) performs error correction processing with respect to the soft-decision value.

Abstract: A frequency offset correction value estimation section (21) receives a signal including a predetermined fixed pattern from a transmission side, thereafter, selects a combination of fixed patterns used in a process of estimating a frequency offset is selected depending on the state of a channel, and an estimation result of the frequency offset calculated by the combination of the fixed patterns is output as a correction value of a determined frequency offset. A frequency offset correction section (22) receives the received signal obtained after the correction is performed for correcting a frequency offset of the received signal on the basis of the correction value, and an equalizer (23) demodulates the received signal by using a predetermined algorithm.

Abstract: Distortion of a received signal due to intersymbol interference as well as to frequency offset is corrected. For this reason, a frequency offset correcting circuit 21 corrects a received signal based on a frequency-offset estimated value. A first CIR estimating circuit 22 estimates CIR estimated values at a first position according to a known training sequence in the corrected received signal. Also, a second estimating circuit 24 updates the CIR estimated values with the LMS algorithm according to the corrected received signals as well as to the decision value outputted from the equalizer 13 with the CIR estimated values at the first position as initial values and obtains CIR estimated values at a second position apart from the first position.

Abstract: A data transmission system, a receiver, and a recording medium in which a re-coder (16) generates pseudo transmission signals based on the virtual received data after a decoder (15) generates virtual received data based on virtual decision data from a virtual decision circuit (12), and a soft-decision circuit (18) outputs soft-decision data so as to decrease the number of different bits between the pseudo transmission signals and the received signals, and the received data are generated based on the soft-decision data.

Abstract: A receiver for soft decision and decoding for deriving an appropriate soft-decision value so as to reduce the error rate at the output of a decoder such as a Viterbi decoder. A length V of transmission sequences that can be generated is set greater than a memory length L of a channel (V>L). By providing as many as 2N (N=2.sup.V) branch metric producing circuits and as many as N add/compare/select apparatus (ACS apparatus) for respective states corresponding to combinations of transmission sequence data of V, the accuracy of a soft-decision value is enhanced. Further, a soft-decision value producing circuit performs a process not based on path metrics but based on survivor metrics. This allows a digital signal processor to easily perform the process.

Abstract: In a receiver, a frequency offset estimating circuit inputs a received signal and a decision value from a decision circuit, and estimates a frequency offset. A CIR estimating circuit inputs the estimated frequency offset, the received signal and the decision value, and estimates CIR. A complex conjugate circuit calculates a complex conjugate of the CIR. A multiplication circuit multiplies the complex conjugate and the received signal. Receiving the multiplied value, the decision circuit outputs a decision value.