Method and system for retransmitting data using systematic polar coding

A hybrid automatic repeat request (HARQ) receiver apparatus for use in generating an output data packet as an estimate of an input data packet transmitted in a communications system employing a HARQ protocol in a HARQ session with a maximum received packet limit m, wherein the maximum received packet limit m is an integer greater than or equal to 2, the HARQ receiver apparatus comprising:

• a receiver frontend configured to receive a received primary packet to produce a primary decoder input data;
• a HARQ decoder configured to process the primary decoder input data and generate a primary estimate of the input data packet;
• an error detector configured to detect errors in the primary estimate of the input data packet and release the primary estimate of the input data packet as the output data packet if no errors are detected in the primary estimate of the input data packet;
• and
• a feedback packet transmitter configured to transmit one of a positive acknowledgement (ACK) or a negative acknowledgement (NACK) depending on, respectively, whether the error detector detects an error in the primary estimate of the input data packet,
• wherein the received primary packet carries a primary codeword from a primary code, wherein the primary codeword is a codeword in the primary code corresponding to an encoding of the input data packet,
• wherein the receiver frontend is further configured, in response to the feedback packet transmitter transmitting k consecutive NACKs, to receive a kth received incremental redundancy (IR) packet to produce a kth IR decoder input data, wherein k is an integer value greater than or equal to 1 and less than or equal to (m−1),
• wherein the HARQ decoder is further configured to process a kth collection of decoder input data and generate a kth IR estimate of the input data packet, wherein the kth collection of decoder input data comprise the primary decoder input data and the jth IR decoder input data for each integer j=1, 2, . . . , k,
• wherein the error detector is further configured to detect errors in the kth IR estimate of the input data packet and release the kth IR estimate of the input data packet as the output data packet if no errors are detected in the kth IR estimate of the input data packet,
• wherein the feedback packet transmitter is further configured to transmit one of a positive acknowledgement (ACK) or a negative acknowledgement (NACK) depending on, respectively, whether the error detector detects an error in the kth IR estimate of the input data packet,
• wherein the kth received IR packet contains a kth IR codeword from a kth IR code, wherein the kth IR codeword is a punctured version of a kth IR mother codeword, wherein the kth IR mother codeword is a codeword from a kth IR mother code, wherein the kth IR mother codeword is the codeword in the kth IR mother code corresponding to a systematic encoding of a kth IR data segment, wherein the kth IR data segment is a subvector of the primary codeword, wherein the systematic encoding of the kth IR data segment comprises a mapping of the kth IR data segment to a systematic segment of the kth IR mother codeword, wherein the systematic segment of the kth IR mother codeword is a subvector of the kth IR mother codeword, wherein the subvector of the kth IR mother codeword carries the kth IR data segment in a systematic manner,
• wherein the punctured version of the kth IR mother codeword contains no elements from the systematic segment of the kth IR mother codeword,
• wherein the HARQ session ends when a positive acknowledgement (ACK) is transmitted in response to a packet received in the HARQ session, and
• wherein a number of received packets in the HARQ session is limited by the maximum received packet limit m.

A hybrid automatic repeat request (HARQ) transmission process for use in transmitting an input data packet in a communications system employing a HARQ protocol in a HARQ session with a maximum transmission limit m, wherein the maximum transmission limit m is an integer greater than or equal to 2, the HARQ transmission process comprising:

• in a primary encoder, receiving an input data packet to start the HARQ session and encoding the input data packet into a primary codeword from a primary code;
• in a packet transmitter, receiving the primary codeword and transmitting the primary codeword inside a primary packet over a communications channel;
• in a systematic incremental redundancy (IR) encoder, selecting a kth IR data segment, encoding the kth IR data segment in a systematic manner into a kth IR mother codeword from a kth IR mother code, and producing a kth IR codeword from the kth IR mother codeword by a puncturing of the kth IR mother codeword,
• wherein the kth IR codeword is received in the packet transmitter and the kth IR codeword is transmitted by the packet transmitter inside a kth IR packet over the communications channel,
• wherein k is an integer greater than or equal to 1 and less than or equal to (m−1),
• wherein the kth IR data segment is a subvector of the primary codeword,
• wherein the kth IR packet is transmitted in response to receiving a kth negative acknowledgement (NACK) in the HARQ session,
• wherein the HARQ session ends when a positive acknowledgement (ACK) is received in response to a packet transmitted in the HARQ session,
• wherein the HARQ session ends when a positive acknowledgement (ACK) is transmitted in response to a packet received in the HARQ session, and
• wherein a number of packets transmitted in the HARQ session is limited by the maximum transmission limit m.

A hybrid automatic repeat request (HARQ) reception process for use in generating an output data packet as an estimate of an input data packet transmitted in a communications system employing a HARQ protocol in a HARQ session with a maximum received packet limit m, wherein the maximum received packet limit m is an integer greater than or equal to 2, the HARQ reception process comprising:

• in a receiver frontend, receiving a received primary packet to produce a primary decoder input data;
• in a HARQ decoder, processing the primary decoder input data and generate a primary estimate of the input data packet;
• in an error detector, detecting errors in the primary estimate of the input data packet and release the primary estimate of the input data packet as the output data packet if no errors are detected in the primary estimate of the input data packet;
• in a feedback packet transmitter, transmitting one of a positive acknowledgement (ACK) or a negative acknowledgement (NACK) depending on, respectively, whether the error detector detects an error in the primary estimate of the input data packet,
• wherein the received primary packet carries a primary codeword from a primary code, wherein the primary codeword is a codeword in the primary code corresponding to an encoding of the input data packet;
• and
• in response to the feedback packet transmitter transmitting k consecutive NACKs, receiving a kth received incremental redundancy (IR) packet in the receiver frontend;
• producing a kth IR decoder input data, wherein k is an integer value greater than or equal to 1 and less than or equal to (m−1);
• processing a kth collection of decoder input data in the HARQ decoder and generating a kth IR estimate of the input data packet, wherein the kth collection of decoder input data comprise the primary decoder input data and the jth IR decoder input data for each integer j=1, 2, . . . , k;
• detecting errors in the kth IR estimate of the input data packet in the error detector and releasing the kth IR estimate of the input data packet as the output data packet if no errors are detected in the kth IR estimate of the input data packet;
• transmitting one of a positive acknowledgement (ACK) or a negative acknowledgement (NACK) from the feedback packet transmitter depending on, respectively, whether the error detector detects an error in the kth IR estimate of the input data packet,
• wherein the kth received IR packet contains a kth IR codeword from a kth IR code, wherein the kth IR codeword is a punctured version of a kth IR mother codeword, wherein the kth IR mother codeword is a codeword from a kth IR mother code, wherein the kth IR mother codeword is the codeword in the kth IR mother code corresponding to a systematic encoding of a kth IR data segment, wherein the kth IR data segment is a subvector of the primary codeword, wherein the systematic encoding of the kth IR data segment comprises a mapping of the kth IR data segment to a systematic segment of the kth IR mother codeword, wherein the systematic segment of the kth IR mother codeword is a subvector of the kth IR mother codeword, wherein the subvector of the kth IR mother codeword carries the kth IR data segment in a systematic manner,
• wherein the punctured version of the kth IR mother codeword contains no elements from the systematic segment of the kth IR mother codeword, and
• wherein a number of received packets in the HARQ session is limited by the maximum received packet limit m.