Receiving apparatus and receiving method in CDMA communication system
AssigneeFujitsu Limited
InventorsShuuichi Murata, Natsuhiko Nakayauchi
Life of this patent
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Abstract
When it is detected that a CRC check is acceptable in Blind Transport Format Detection(BTFD) processing, the BTFD processing is halted from this moment onward, the number of bits of voice code of each class is decided based upon the bit rate of each class in a bit-rate combination that prevails when the CRC check is acceptable, the voice code of each class is demultiplexed from receive data based upon the number of bits and the demultiplexed voice code is input to a voice codec.
Claims12
A receiving apparatus in a communication system in which voice code is divided into a plurality of classes, the voice code in each class is expressed by a number of bits that conforms to a prescribed bit rate, a check code of a fixed length is attached to voice code of one class, the voice code of each class is subjected to error-correction encoding processing, and voice code that has undergone error-correction encoding processing in each class is transmitted upon being multiplexed in such a manner that the class with the attached check code is brought to the forefront, comprising:
- a bit-rate candidate holding unit for holding a plurality of bit-rate combination candidates of each of the classes;
- a decoding processing unit for applying error-correction decoding processing to receive data corresponding to the class with the attached check code on the assumption that the voice code of the class with the attached check code is expressed by a number of bits that conforms to the bit rate of the class with the attached check code in each of the bit-rate combination candidates;
- investigating means for investigating whether result of decoding is correct using the check code;
- and
- a bit-count discriminating unit which, when it is judged by said investigation that the result of decoding is correct, is for discriminating that the numbers of bits conforming to the bit rates of each of the classes in the bit-rate combination candidate prevailing at this time are a numbers of bits that express the voice codes of each of the classes.
A receiving apparatus, comprising:
- receiving means for receiving a signal that has been modulated by variable-length data that includes error-detection data;
- error detecting means for selecting a plurality of data-length candidates in order, extracting an amount equivalent to the selected data length with regard to a demodulated signal and performing error detection using the error-detection data;
- and data length determination means for determining a candidate of a data length as a data length of the variable length in a case where an error could not be detected by said error detecting means, wherein characterized in that:
- said data length determination means determines, as the data length of the variable length, a candidate of an initial data length for which an error could not be detected by said error detecting means.
A receiving method in a CDMA communication system in which voice code of a prescribed transmission time interval is divided into a plurality of classes, the voice code in each class is expressed by a number of bits that conforms to a prescribed bit rate, a check code of a fixed length is attached to voice code of one class, the voice code of each class is subjected to error-correction encoding processing, and voice code that has undergone error-correction encoding processing in each class is transmitted upon being multiplexed in such a manner that the class with the attached check code is brought to the forefront, comprising steps of:
- holding a plurality of bit-rate combination candidates of each of the classes;
- applying error-correction decoding processing to receive data corresponding to the class with the attached check code on the assumption that the voice code of the class with the attached check code is expressed by a number of bits that conforms to the bit rate of the class with the attached check code in each of the bit-rate combination candidates;
- investigating whether result of decoding is correct using the check code and, when it is judged by said investigation that the result of decoding is correct, discriminating that the numbers of bits conforming to the bit rates of each of the classes in the bit-rate combination candidate prevailing at this time are a numbers of bits that express the voice codes of each of the classes, and ending processing for discriminating the number of bits;
- applying error-correction decoding processing to classes other than the class with the attached check code, based upon the discriminated numbers of bits of the voice code of each of the classes;
- and
- reconstructing a voice signal using the voice code of each of the classes.
A receiving method according to claim 11, further comprising steps of:
- when it has been clarified by said investigation that the result of decoding is correct, storing the bit-rate combination candidate prevailing at this time;
- and
- when the voice code of each of the classes is demultiplexed from receive data and input to a voice reconstruction unit every transmission time interval, applying error-correction decoding processing to the receive data on the assumption that the voice code of the class with the attached check code is expressed by a number of bits that conforms to the bit rate of the class with the attached check code in the bit-rate combination candidate that has been stored.
Dependencies are inferred from the claim text.