Retransmission control method and communications device
AssigneeMitsubishi Electric Corporation
InventorWataru Matsumoto
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Abstract
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.
Claims9
A retransmission control method for a communications device that transmits a codeword to another communications device using low-density parity check codes as error correcting codes, the retransmission control method comprising:
- generating N parity check matrices optimized at N code rates, respectively, where N is a positive integer, wherein a k-th code rate is lower than a (k−1)-th code rate, where k is a positive integer from 2 to N;
- converting a first parity check matrix so that the first parity check matrix contains a check symbol generator matrix;
- generating a generator matrix containing the check symbol generator matrix;
- transmitting the codeword generated by using the generator matrix to the another communications device;
- generating, when the communications device receives a negative acknowledgment from the another communications device in response to the codeword, a first additional parity by using a second parity check matrix;
- retransmitting the first additional parity to the another communications device;
- generating, when the communications device receives a negative acknowledgment from the another communications device in response to a (k−1)-th additional parity generated by using a k-th parity check matrix, a k-th additional parity by using the (k+1)-th parity check matrix;
- and
- retransmitting the k-th additional parity to the another communications device.
A communications device that transmits a codeword to another communications device using low-density parity check codes as error correcting codes, the communications device comprising:
- a retransmission control unit that controls a retransmission when the communications device receives a negative acknowledgement from the another communications device;
- an encoding unit that includes
- a parity-check-matrix generating unit that generates N parity check matrices optimized at N code rates, respectively, where N is a positive integer, wherein a k-th code rate is lower than a (k−1)-th code rate, where k is a positive integer from 2 to N;
- a converting unit that converts a first parity check matrix so that the first parity check matrix contains a check symbol generator matrix;
- a generator-matrix generating unit that generates a generator matrix containing the check symbol generator matrix;
- and
- a codeword generating unit that generates the codeword by using the generator matrix;
- and
- a modulation unit that applies predetermined digital modulation to the codeword and transmits the codeword to the another communications device, wherein
- when the communications device receives a negative acknowledgement from the another communications device in response to the codeword, the encoding unit generates a first additional parity by using a second parity check matrix and the modulation unit applies predetermined digital modulation to the first additional parity, and
- when the communications device receives a negative acknowledgement from the another communications device in response to a (k−1)-th additional parity generated by using a k-th parity check matrix, the encoding unit generates a k-th additional parity by using the (k+1)-th parity check matrix and the modulation unit applies predetermined digital modulation to the k-th additional parity.
A communications device comprising:
- a unit that generates Low-Density Parity-Check codes as error correcting codes, including:
- generating parity check matrix optimized at respective predetermined code rates,
- converting a first parity check matrix so that the first parity check matrix contains a check symbol generator matrix, and
- generating a generator matrix containing the check symbol generator matrix;
- a unit that transmits a codeword that has been encoded at a predetermined code rate of initial transmission, and transmit an additional parity in retransmission, wherein the generator matrix is used to generate the additional parity.
Dependencies are inferred from the claim text.