摘要:
A two-step reaction method for the transesterification of fats and oils, comprising hydrolyzing fats and oils to produce diglycerides by reacting said fats or oils with lipase; esterifying said digylcerides and to produce triglycerides by reacting said diglycerides with at least one fatty acid.
摘要:
When an error correction decoding unit 26 of a data reception device 2 fails in error correction decoding of a codeword, an MIMO processing unit 15 of a data transmission device 1 deforms transmitted codewords according to a predetermined rule, and transmits the codewords, and the error correction decoding unit 26 of the data reception device 2 reproduces data by using the deformed codewords. As a result, not only the noise but the interference wave components can be reduced, and the success rates of the demodulation and error correction decoding can be improved greatly.
摘要:
A regular quasi-cyclic matrix is generated in which specific regularity is given to cyclic permutation matrices. A mask matrix capable of supporting a plurality of encoding rates is generated. A specific cyclic permutation matrix in the regular quasi-cyclic matrix is converted into a zero-matrix using a mask matrix corresponding to a specific encoding rate to generate an irregular masking quasi-cyclic matrix. An irregular parity check matrix with an LDGM structure is generated in which the masking quasi-cyclic matrix and a matrix in which the cyclic permutation matrices are arranged in a staircase manner are arranged in a predetermined location.
摘要:
A communication method that performs low density parity check (LDPC) coding to a data stream to be transmitted in a radio communication system by using a parity check matrix that has columns with uneven column degrees. The columns are arranged in a descending order of the column degrees. The communication method includes segmenting a code word into a plurality of data streams depending on number of data bits that are assignable to a radio resource block that is a unit of radio transmission, and assigning a segmented data stream having a higher column degree to a radio resource block with higher quality.
摘要:
A communication system according to the present invention comprises a transmitter for performing low-density parity-check (LDPC) coding and a receiver for performing LDPC decoding based on the “Sum-Product algorithm”, and performing a synchronous control and a user detection by using a sum of absolute values of logarithm likelihood ratio of the posterior probability of each bit that is output as a decoding result.
摘要:
A communication system includes a transmitter and a receiver. The transmitter transmits a signal encoded by a low-density parity-check (LDPC) coding. The receiver includes a decoder, a phase error estimator, and a correction unit. The decoder decodes the signal at a plurality of sampling points using a single iteration of sum-product decoding. The phase error estimator estimates a phase error of the signal using minimum mean square error (MMSE) estimation and soft decision information obtained by the sum-product decoding. The correction unit corrects the signal using the phase error.
摘要:
A communication system sets the data transmission time which is the time suitable for data transmission and the quasi-data transmission time which is the time other than the data transmission time in a period in accordance with the transmission path. Further, bits are assigned and transmitted in such a manner that data for one period can be transmitted during the data transmission period for that period and the data can be uniformly distributed over the data transmission time for the period.
摘要:
A retransmission control method comprising: generating N parity check matrices; generating a generator matrix containing a check symbol generator matrix contained in the first parity check matrix; transmitting the codeword generated by using the generator matrix to another communications device; generating, when the communications device receives a NAK in response to the codeword, a first additional parity by using the second parity check matrix; and retransmitting the first additional parity to the another communications device.
摘要:
In the communication system which performs the data communication by the discrete multi-tone modem scheme between a plurality of data communication units using the time-division half-duplex communication function, the ratio between the data transmission time suitable for data communication and the quasi-data transmission time dynamically changes within one period. Further, bits are assigned in such a manner that the data of one period can be transmitted during the data transmission time of that period. Dummy bits are assigned to the portions of the data transmission time to which the data to be transmitted has not been assigned.
摘要:
A method of generating a check matrix for an LDPC code includes determining a coding rate, generating a basic matrix that satisfies predetermined conditions, determining a number of columns of a check matrix, substituting rows of the basic matrix based on a specific relational equation, provisionally searching an ensemble of weights by executing Gaussian approximation, deleting rows of the basic matrix after the permutation in order from the bottom by considering the number of rows after a division, searching an optimal ensemble of weights by executing Gaussian approximation based on a predetermined condition after row deletion, and dividing at random the weights of the basic matrix after the row deletion based on the optimal ensemble.