Methods, apparatus and systems for reduced complexity polar codes based on modified cyclic-redundancy-check (CRC) procedures
In certain representative embodiments, methods, apparatus and systems are provided for the selection of component codes for input as cyclic redundancy check (CRC) bits during polar encoding. The component polar codes and particular encoded bits in these component codes that will be used in CRC calculation can be selected. A CRC calculation may be performed based on the component codes and the selected encoded bits. The calculated CRC bits may be appended to a header part of the input bits of the polar encoder. Polar encoding may then be performed using the input bits which include the calculated CRC bits appended thereto. For example, the polar encoding may skip encoding levels used in accordance with the component code selection. The polar encoding may have improved complexity and/or latency characteristics. In certain representative embodiments, methods, apparatus and systems are provided for polar decoding having improved complexity and/or latency characteristics.
1. A method implemented by a wireless transmit/receive unit (WTRU), the method comprising:
polar encoding a plurality of information bits and one or more cyclic redundancy check (CRC) bits, wherein the polar encoding is performed according to a code construction of the plurality of information bits and the one or more CRC bits, and wherein the one or more CRC bits are determined using a plurality of output bits of one or more component polar codes of the polar encoding; and
sending a transmission including information indicating the polar encoded information bits and the polar encoded one or more CRC bits.
2. The method of claim 1 , further comprising:
determining the code construction from among a plurality of code constructions using any of any of a modulation and coding scheme (MCS), a code rate, a decoding method, and/or a target latency associated with the transmission.
3. The method of claim 1 , wherein the code construction includes a plurality of frozen bits and a plurality of unfrozen bits which correspond to input bit positions for the polar encoding, and wherein the plurality of unfrozen bits include the plurality of information bits and the one or more CRC bits.
4. The method of claim 3 , wherein the plurality of output bits of the one or more component polar codes are associated with the polar encoding of one or more of the plurality of information bits and/or one or more of the frozen bits.
5. The method of claim 1 , wherein the one or more component polar codes include any of a full-rate component polar code, a zero-rate component polar code, a repetition component polar code, and/or a single parity check component polar code.
6. The method of claim 5 , wherein the repetition component polar code includes a single information bit, a code rate of the repetition component polar code is
1
N
v
,
and N v is a length of the repetition component polar code.
7. The method of claim 5 , wherein the single parity check component polar code includes a single parity check bit, a code rate of the single parity check component polar code is
N
v
-
1
N
v
,
and N v is a length of the repetition component polar code.
8. The method of claim 1 , further comprising:
determining one or more groups of the plurality of output bits of the component polar codes based on a timing index of the plurality of output bits; and
determining the one or more CRC bits from the determined one or more groups.
9. The method of claim 1 , wherein at least one of the CRC bits is determined from two or more of the output bits which are associated with different timing indices of the polar encoding.
10. The method of claim 1 , wherein a first one of the CRC bits is determined from a first set of the output bits of the one or more component polar codes having a first code rate, and a second one of the CRC bits is determined from a second set of the output bits of the one or more component polar codes having a second code rate different than the first code rate.
11. A wireless transmit/receive unit (WTRU) comprising:
a processor, a memory, and a transceiver which are configured to:
polar encode a plurality of information bits and one or more cyclic redundancy check (CRC) bits, wherein the polar encoding is performed according to a code construction of the plurality of information bits and the one or more CRC bits, wherein the one or more CRC bits are determined using a plurality of output bits of one or more component polar codes of the polar encoding, and
send a transmission including information indicating the polar encoded information bits and the polar encoded one or more CRC bits.
12. The WTRU of claim 11 , wherein the processor, the memory, and the transceiver are configured to:
determine the code construction from among a plurality of code constructions using any of any of a modulation and coding scheme (MCS), a code rate, a decoding method, and/or a target latency associated with the transmission.
13. The WTRU of claim 11 , wherein the code construction includes a plurality of frozen bits and a plurality of unfrozen bits which correspond to input bit positions for the polar encoding, and wherein the plurality of unfrozen bits include the plurality of information bits and the one or more CRC bits.
14. The WTRU of claim 13 , wherein the plurality of output bits of the one or more component polar codes are associated with the polar encoding of one or more of the plurality of information bits and/or one or more of the frozen bits.
15. The WTRU of claim 11 , wherein the one or more component polar codes include any of a full-rate component polar code, a zero-rate component polar code, a repetition component polar code, and/or a single parity check component polar code.
16. The WTRU of claim 15 , wherein the repetition component polar code includes a single information bit, a code rate of the repetition component polar code is
1
N
v
,
and N v is a length of the repetition component polar code.
17. The WTRU of claim 15 , wherein the single parity check component polar code includes a single parity check bit, a code rate of the single parity check component polar code is
N
v
-
1
N
v
,
and N v is a length of the repetition component polar code.
18. The WTRU of claim 11 , wherein the processor, the memory, and the transceiver are is configured to:
determine one or more groups of the plurality of output bits of the component polar codes based on a timing index of the plurality of output bits, and
determine the one or more CRC bits from the one or more determined groups.
19. The WTRU of claim 11 , wherein at least one of the CRC bits is determined from two or more of the output bits which are associated with different timing indices of the polar encoding.
20. The WTRU of claim 11 , wherein a first one of the CRC bits is determined from a first set of the output bits of the one or more component polar codes having a first code rate, and a second one of the CRC bits is determined from a second set of the output bits of the one or more component polar codes having a second code rate different than the second code rate.