Circular buffer based hybrid automatic retransmission request for polar codes

An apparatus for wireless communications, comprising:

• at least one processor configured to:
• determine a target coding rate (RT) for transmitting a group of K information bits, based on a first coding rate (R1) corresponding to a first target block error rate (BLER) for a first transmission of a first redundancy version (RV) of the group and a second coding rate (R2) corresponding to a second target BLER for a last transmission of a last RV of the group,
• determine a circular buffer size (N) of a circular buffer for use in transmitting the first RV and the last RV of the group, wherein, in order to determine the circular buffer size (N), the at least one processor is further configured to:
• obtain a minimum supported coding rate (Rmin);
• calculate a first buffer size (NR) as a minimum integral power of two which is not less than K/Rmin,
• calculate a second buffer size (NT) as a minimum integral power of two which is not less than K/RT;
• obtain a maximum coded block size (Nmax);
• and
• calculate N as a minimum of NR, NT, and Nmax;
• generate encoded information bits from the K information bits using a polar code having a mother code size of N;
• write the encoded information bits to the circular buffer;
• determine a maximum number of retransmissions, based on a latency requirement for the group;
• generate, based on the maximum number of retransmissions, different RVs from the encoded information bits in the circular buffer, wherein each RV of the different RVs is based on a corresponding target BLER;
• and
• transmit the first RV via a wireless medium;
• and
• a memory coupled with the at least one processor.

An apparatus for wireless communications, comprising:

• means for determining a target coding rate (RT) for transmitting a group of K information bits, based on a first coding rate (R1) corresponding to a first target block error rate (BLER) for a first transmission of a first redundancy version (RV) of the group and a second coding rate (R2) corresponding to a second target BLER for a last transmission of a last RV of the group,
• means for determining a circular buffer size (N) of a circular buffer for use in transmitting the first RV and the last RV of the group, wherein the means for determining the circular buffer size (N) comprise:
• means for obtaining a minimum supported coding rate (Rmin);
• means for calculating a first buffer size (NR) as a minimum integral power of two which is not less than K/Rmin,
• means for calculating a second buffer size (NT) as a minimum integral power of two which is not less than K/RT;
• means for obtaining a maximum coded block size (Nmax);
• and
• means for calculating N as a minimum of NR, NT, and Nmax;
• means for generating encoded information bits from the K information bits using a polar code having a mother code size of N;
• means for writing the encoded information bits to the circular buffer;
• means for determining a maximum number of retransmissions, based on a latency requirement for the group;
• means for generating, based on the maximum number of retransmissions, different RVs from the encoded information bits in the circular buffer, wherein each RV of the different RVs is based on a corresponding target BLER;
• and
• means for transmitting the first RV via a wireless medium.

A non-transitory computer-readable medium, comprising:

• instructions that, when executed by at least one processor, cause the at least one processor to:
• determine a target coding rate (RT) for transmitting a group of K information bits, based on a first coding rate (R1) corresponding to a first target block error rate (BLER) for a first transmission of a first redundancy version (RV) of the group and a second coding rate (R2) corresponding to a second target BLER fora last transmission of a last RV of the group,
• determine a circular buffer size (N) of a circular buffer for use in transmitting the first RV and the last RV of the group, wherein, in order to determine the circular buffer size (N), the instructions further cause the at least one processor to:
• obtain a minimum supported coding rate (Rmin);
• calculate a first buffer size (NR) as a minimum integral power of two which is not less than K/Rmin,
• calculate a second buffer size (NT) as a minimum integral power of two which is not less than K/RT;
• obtain a maximum coded block size (Nmax);
• and
• calculate N a minimum of NR, NT, and Nmax;
• generate encoded information bits from the K information bits using a polar code having a mother code size of N;
• write the encoded information bits to the circular buffer;
• determine a maximum number of retransmissions, based on a latency requirement for the group;
• generate, based on the maximum number of retransmissions, different RVs from the encoded information bits in the circular buffer, wherein each RV of the different RVs is based on a corresponding target BLER;
• and
• transmit the first RV via a wireless medium.