Rate-matching scheme for polar codes
Aspects of the disclosure relate to rate-matching a stream of bits encoded using polar codes. An exemplary method generally includes determining a mother code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (Rmin), a control information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum mother code size (Nmax), encoding a stream of bits using a polar code of size (N, K) and storing the encoded stream of bits in a circular buffer, and performing rate-matching on the stored encoded stream of bits based, at least in part, on a comparison among the mother code size (N), the control information size of the encoded stream of bits (K), and the number of coded bits for transmission (E).
1. A method of wireless communications performed by a wireless communications device using a radio access technology (RAT), comprising:
determining a code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (R min ), an information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum supported code size (N max );
encoding a stream of bits using a polar code (N,K) to output the encoded stream of bits;
performing rate-matching on the encoded stream of bits based, at least in part, on a comparison based on the code size (N), the information size of the encoded stream of bits (K), or the number of coded bits for transmission (E); and
transmitting the rate-matched encoded stream of bits using the RAT;
wherein N is equal to a minimum of:
a minimum power of two integer that is not less than K/R min ;
a minimum power of two integer that is not less than E; or
the maximum supported code size (N max ).
2. The method of claim 1 , wherein performing rate matching on the encoded stream of bits comprises repeating a first number of encoded bits when E>N.
3. The method of claim 2 , wherein the first number of encoded bits is equal to E−N bits, starting from a zeroth position in a circular buffer and proceeding clockwise around the circular buffer.
4. The method of claim 2 , wherein the first number of encoded bits is repeated at the end of the encoded stream of bits in a circular buffer.
5. The method of claim 2 , wherein performing rate matching on the encoded stream of bits comprises:
puncturing a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shortening a third number of encoded bits when E<N and when K/E>β.
6. The method of claim 1 , further comprising storing the encoded stream of bits in a circular buffer.
7. The method of claim 1 , wherein performing rate matching on the encoded stream of bits comprises shortening a third number of encoded bits when E<N and when K/E>β, wherein β is a real value ranging from 0 to 1.
8. The method of claim 7 , wherein the third number of encoded bits is equal to N−E bits, starting from position N−1 in the circular buffer and proceeding counter-clockwise around the circular buffer.
9. The method of claim 1 , wherein the minimum supported code rate is 1/6.
10. The method of claim 1 , wherein performing rate matching on the encoded stream of bits comprises puncturing a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1.
11. The method of claim 10 , wherein the second number of encoded bits is equal to N−E bits, starting from a zeroth position in a circular buffer and proceeding clockwise around the circular buffer.
12. The method of claim 1 , wherein performing rate matching on the encoded stream of bits comprises:
puncturing a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shortening a third number of encoded bits when E<N and when K/E>β.
13. An apparatus for wireless communications using a radio access technology (RAT), comprising:
a memory comprising executable instructions; and
at least one processor configured to execute the executable instructions and cause the apparatus to:
determine a code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (R min ), an information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum supported code size (N max );
encode a stream of bits using a polar code (N,K) to output the encoded stream of bits;
perform rate-matching on the encoded stream of bits based, at least in part, on a comparison based on the code size (N), the information size of the encoded stream of bits (K), or the number of coded bits for transmission (E);
transmit the rate-matched encoded stream of bits using the RAT; and
wherein N is equal to a minimum of:
a minimum power of two integer that is not less than K/R min ;
a minimum power of two integer that is not less than E; or
the maximum supported code size (N max ).
14. The apparatus of claim 13 , wherein, in order to perform the rate matching on the encoded stream of bits, the at least one processor is configured to:
puncture a second number of encoded bits when E<N and when K/E<= 62 , wherein β is a real value ranging from 0 to 1; and
shorten a third number of encoded bits when E<N and when K/E>β.
15. The apparatus of claim 13 , wherein, in order to perform the rate matching on the encoded stream of bits, the at least one processor is configured to puncture by puncturing a second number of encoded bits when if E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1.
16. The apparatus of claim 15 , wherein the second number of encoded bits is equal to N−E bits, starting from a zeroth position in a circular buffer and proceeding clockwise around the circular buffer.
17. The apparatus of claim 13 , wherein, in order to perform the rate matching on the encoded stream of bits, the at least one processor is configured to shorten a third number of encoded bits when E<N and when K/E>β, wherein β is a real value ranging from 0 to 1.
18. The apparatus of claim 17 , wherein the third number of encoded bits is equal to N−E bits, starting from position N−1 in a circular buffer and proceeding counter-clockwise around the circular buffer.
19. The apparatus of claim 13 , wherein the minimum supported code rate is 1/6.
20. The apparatus of claim 13 , wherein, in order to perform the rate matching on the encoded stream of bits, the at least one processor is configured to repeat a first number of encoded bits when E>N.
21. The apparatus of claim 20 , wherein the first number of encoded bits is equal to E−N bits, starting from a zeroth position in a circular buffer and proceeding clockwise around the circular buffer.
22. The apparatus of claim 20 , wherein the at least one processor is configured to repeat first number of encoded bits at the end of the encoded stream of bits in a circular buffer.
23. The apparatus of claim 20 , wherein, in order to perform the rate matching on the encoded stream of bits, the at least one processor is configured to:
puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shorten a third number of encoded bits when E<N and when K/E>β, wherein β is a real value ranging from 0 to 1.
24. A non-transitory computer-readable medium for wireless communications performed by a wireless communications device using a radio access technology (RAT), comprising:
instructions that, when executed by at least one processor, configure the at least one processor to:
determine a code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (R min ), an information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum supported code size (N max );
encode a stream of bits using a polar code (N,K) to output the encoded stream of bits;
perform rate-matching on the encoded stream of bits based, at least in part, on a comparison based on the code size (N), the information size of the encoded stream of bits (K), or the number of coded bits for transmission (E); and
transmit the rate-matched encoded stream of bits using the RAT; and
a memory coupled with the at least one processor;
wherein N is equal to a minimum of:
a minimum power of two integer that is not less than K/R min ;
a minimum power of two integer that is not less than E; or
the maximum supported code size (N max ).
25. The non-transitory computer-readable medium of claim 24 , wherein the instructions that configure the at least one processor to perform rate matching on the encoded stream of bits configure the at least one processor to puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1.
26. The non-transitory computer-readable medium of claim 24 , wherein the instructions that configure the at least one processor to perform rate matching on the encoded stream of bits configure the at least one processor to:
puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shorten a third number of encoded bits when E<N and when K/E>β.
27. The non-transitory computer-readable medium of claim 24 , wherein the instructions that configure the at least one processor to perform rate matching on the encoded stream of bits are configure the at least one processor to repeat a first number of encoded bits when E≥N.
28. The non-transitory computer-readable medium of claim 27 , wherein the first number of encoded bits is equal to E−N bits, starting from a zeroth position in a circular buffer and proceeding clockwise around the circular buffer.
29. The non-transitory computer-readable medium of claim 27 , wherein the instructions that configure the at least one processor to perform rate matching on the encoded stream of bits configure the at least one processor to:
puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shorten a third number of encoded bits when E<N and when K/E>β.
30. The non-transitory computer-readable medium of claim 26 , wherein the instructions that configure the at least one processor to perform rate matching on the encoded stream of bits configure the at least one processor to shorten a third number of encoded bits when E<N and when K/E>β, wherein β is a real value ranging from 0 to 1.
31. An apparatus for wireless communications performed by a wireless communications device using a radio access technology (RAT), comprising:
means for determining a code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (R min ), an information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum supported code size (N max );
means for encoding a stream of bits using a polar code (N,K) to output the encoded stream of bits;
means for performing rate-matching on the encoded stream of bits based, at least in part, on a comparison based on the code size (N), the information size of the encoded stream of bits (K), or the number of coded bits for transmission (E); and
means for transmitting the rate-matched encoded stream of bits using the RAT;
wherein N is equal to a minimum of:
a minimum power of two integer that is not less than K/R min ;
a minimum power of two integer that is not less than E; or
the maximum supported code size (N max ).
32. The apparatus of claim 31 , wherein means for performing rate matching on the encoded stream of bits are configured to repeat a first number of encoded bits when E>N.
33. The apparatus of claim 32 , wherein the first number of encoded bits is equal to E−N bits, starting from a zeroth position in a circular buffer and proceeding clockwise around the circular buffer.
34. The apparatus of claim 32 , wherein the means for performing rate matching on the encoded stream of bits are configured to:
puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shorten a third number of encoded bits when E<N and when K/E>β.
35. The apparatus of claim 31 , wherein the means for performing rate matching on the encoded stream of bits are configured to puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1.
36. The apparatus of claim 31 , wherein the means for performing rate matching on the encoded stream of bits are configured to:
puncture a second number of encoded bits when E<N and when K/E<=β, wherein β is a real value ranging from 0 to 1; and
shorten a third number of encoded bits when E<N and when K/E>β.
37. The apparatus of claim 31 , wherein the means for performing rate matching on the encoded stream of bits are configured to shorten a third number of encoded bits when E<N and when K/E>β, wherein β is a real value ranging from 0 to 1.