Systems and methods for HARQ transmission and retransmission using multiple code words

An apparatus, comprising:

• a memory;
• a transceiver;
• and
• a processor in communication with the memory and the transceiver, wherein the processor is configured to:
• transmit an original transmission in a hybrid automatic repeat request (HARD) process via the transceiver, the original transmission having a first transport block transmitted on a first code word and a second transport block transmitted on a second code word, each transport block of the first transport block and the second transport block including multiple code blocks grouped into code block groups, wherein a first code block group of the code block groups includes a first code block of the multiple code blocks;
• receive, via the transceiver, a negative acknowledgment in response to the original transmission, the negative acknowledgment indicating, at a code block group level, that a subset of the code block groups including at least the first code block group was not successfully received, the subset of the code block groups including fewer code block groups than the original transmission;
• determine a list of code block groups to be included in a retransmission based on a retransmission grant and calculate a nominal payload size of code words in the list of code block groups to be included in the retransmission;
• allocate the subset of code block groups or code blocks within the subset of code block groups to the first code word and the second code word proportionately according to the nominal payload size of each code word in the retransmission;
• and
• transmit the subset of the code block groups on at least one of the first code word or the second code word in the retransmission in the HARQ process via the transceiver,
• wherein if the first code block was transmitted on the first code word in the original transmission then the first code block is transmitted on only the second code word in the retransmission, and if the first code block was transmitted on the second code word in the original transmission the first code block is transmitted on only the first code word in the retransmission.

An apparatus, comprising:

• means for transmitting an original transmission in a hybrid automatic repeat request (HARD) process, the original transmission having a first transport block transmitted on a first code word and a second transport block transmitted on a second code word, each transport block of the first transport block and the second transport block including multiple code blocks grouped into code block groups, wherein a first code block group of the code block groups includes a first code block of the multiple code blocks;
• means for receiving a negative acknowledgment in response to the original transmission, the negative acknowledgment indicating, at a code block group level, that a subset of the code block groups including at least the first code block group was not successfully received, the subset of the code block groups including fewer code block groups than the original transmission, wherein the means for receiving the negative acknowledgment is configured to determine a list of code block groups to be included in a retransmission based on a retransmission grant, and;
• and
• means for transmitting the subset of the code block groups on at least one of the first code word or the second code word in the retransmission in the HARQ process, wherein the means for transmitting is configured to calculate a nominal payload size of code words in the list of code block groups to be included in the retransmission and allocate the subset of code block groups to the first code word and the second code word proportionately according to the nominal payload size of each code word in the retransmission,
• wherein if the first code block was transmitted on the first code word in the original transmission then the first code block is transmitted on only the second code word in the retransmission, and if the first code block was transmitted on the second code word in the original transmission the first code block is transmitted on only the first code word in the retransmission.

A non-transitory computer-readable medium storing computer code executable by a processor for wireless communications, the computer-readable medium comprising code to:

• transmit an original transmission in a hybrid automatic repeat request (HARQ) process, the original transmission having a first transport block transmitted on a first code word and a second transport block transmitted on a second code word, each transport block of the first transport block and the second transport block including multiple code blocks grouped into code block groups, wherein a first code block group of the code block groups includes a first code block of the multiple code blocks;
• receive a negative acknowledgment in response to the original transmission, the negative acknowledgment indicating, at a code block group level, that a subset of the code block groups including at least the first code block group was not successfully received, the subset of the code block groups including fewer code block groups than the original transmission;
• determine a list of code block groups to be included in the retransmission based on a retransmission grant and calculate a nominal payload size of code words in the list of code block groups to be included in the retransmission;
• allocate the subset of code block groups or code blocks within the subset of code block groups to the first code word and the second code word proportionately according to the nominal payload size of each code word in the retransmission;
• and
• transmit the subset of the code block groups on at least one of the first code word or the second code word in a retransmission in the HARQ process,
• wherein if the first code block was transmitted on the first code word in the original transmission then the first code block is transmitted on only the second code word in the retransmission, and if the first code block was transmitted on the second code word in the original transmission the first code block is transmitted on only the first code word in the retransmission.