Method and apparatus for encoding data using a polar code
Embodiment techniques map parity bits to sub-channels based on their row weights. The row weight for a sub-channel may be viewed as the number of “ones” in the corresponding row of the Kronecker matrix or as a power of 2 with the exponent (i.e. the hamming weight) being the number of “ones” in the binary representation of the sub-channel index (further described below). In one embodiment, candidate sub-channels that have certain row weight values are reserved for parity bit(s). Thereafter, K information bits may be mapped to the K most reliable remaining sub-channels, and a number of frozen bits (e.g. N−K) may be mapped to the least reliable remaining sub-channels. Parity bits may then mapped to the candidate sub-channels, and parity bit values are determined based on a function of the information bits.
1. A method for a device for encoding data, the method comprising:
allocating one or more sub-channels for one or more parity bits based on row weights for sub-channels in a subset of a set of sub-channels; and
mapping information bits to remaining sub-channels in the set of sub-channels based on a reliability of the remaining sub-channels without mapping the information bits to the one or more sub-channels allocated for the one or more parity bits,
encoding the information bits and the one or more parity bits using a polar code to obtain an encoded bit stream; and
transmitting the encoded bit stream.
2. The method of claim 1 , wherein the row weight for a sub-channel represents the number of ones in a row of a Kronecker matrix, the row corresponding to the sub-channel.
3. The method of claim 1 , wherein the row weights comprise at least a minimum row weight.
4. The method of claim 3 , wherein allocating one or more sub-channels for one or more parity bits based on row weights for sub-channels in a subset of a set of sub-channels comprises:
allocating, for the one or more parity bits, a number of sub-channels having a row weight equal to the minimum row weight in the subset of sub-channels.
5. The method of claim 4 , wherein the number of sub-channels allocated is one.
6. The method of claim 4 , wherein the sub-channels in the set are ordered based on their reliabilities to form an ordered sequence of sub-channels, and wherein the subset of sub-channels comprises a most reliable subset of sub-channels in the ordered sequence.
7. The method of claim 4 , wherein the most reliable subset of sub-channels comprises K sub-channels for carrying the information bits.
8. The method of claim 4 , where the most reliable subset of sub-channels comprises K+F P sub-channels, where K is an information block length associated with the information bits, and F p indicates a number of the one or more parity bits.
9. The method of claim 4 , wherein a most reliable sub-channel having a row weight equal to the minimum row weight in the subset of sub-channels is allocated for the one or more parity bits.
10. The method of claim 1 , wherein the one or more parity bits include one or more parity check (PC) bits.
11. The method of claim 10 , wherein encoding the information bits and the one or more PC bits using a polar code to obtain the encoded bit stream comprises:
determining one or more values for the one or more PC bits as a function of values of the information bits; and
mapping the one or more PC bits to at least the one or more sub-channels allocated for the PC bits.
12. A device for encoding data with a polar code, the device being configured to:
allocate one or more sub-channels for one or more parity bits based on row weights for sub-channels in a subset of a set of sub-channels; and
map information bits to remaining sub-channels in the set of sub-channels based on a reliability of the remaining sub-channels without mapping the information bits to the one or more sub-channels allocated for the one or more parity bits,
encode the information bits and the one or more parity bits using a polar code to obtain an encoded bit stream; and
transmit the encoded bit stream.
13. The device of claim 12 , wherein the row weight for a sub-channel represents the number of ones in a row of a Kronecker matrix, the row corresponding to the sub-channel.
14. The device of claim 12 , wherein the row weights comprise at least a minimum row weight.
15. The device of claim 14 , wherein to allocate one or more sub-channels for one or more parity bits based on row weights for sub-channels in a subset of a set of sub-channels, the device being further configured to:
allocate, for the one or more parity bits, a number of sub-channels having a row weight equal to the minimum row weight in the subset of sub-channels.
16. The device of claim 15 , wherein the number of sub-channels allocated is one.
17. The device of claim 15 , wherein the sub-channels in the set are ordered based on their reliabilities to form an ordered sequence of sub-channels, and wherein the subset of sub-channels comprises a most reliable subset of sub-channels in the ordered sequence.
18. The device of claim 15 , wherein the most reliable subset of sub-channels comprises K sub-channels for carrying the information bits.
19. The device of claim 15 , where the most reliable subset of sub-channels comprises K+F P sub-channels, where K is an information block length associated with the information bits, and F p indicates a number of the one or more parity bits.
20. The device of claim 15 , wherein a most reliable sub-channel having a row weight equal to the minimum row weight in the subset of sub-channels is allocated for the one or more parity bits.
21. The device of claim 20 , wherein the one or more parity bits include one or more parity check (PC) bits.
22. The device of claim 21 , wherein to encode the information bits and the one or more PC bits using a polar code to obtain the encoded bit stream, the device being further configured to:
determine one or more values for the one or more PC bits as a function of values of the information bits; and
map the one or more PC bits to at least the one or more sub-channels allocated for the PC bits.