Information processing method, apparatus, communications device, and communications system
An information processing method, an apparatus, a communications device, and a communications system are provided. The communications device is configured to: obtain a starting position in a buffer sequence W for an output bit sequence, and determine the output bit sequence from the buffer sequence W based on the starting position, where a value of the starting position is one element in {p 0 , p 1 , p 2 , . . . , p k max −1 }, 0≤k<k max , 0≤p k <N CB , p k is an integer, k is an integer, N CB is a length of the buffer sequence W, k max is an integer greater than or equal to 4, and there are two or more different neighboring intervals in {p 0 , p 1 , p 2 , . . . , p k max −1 }. A bit sequence for initial transmission or retransmission is properly determined, so that decoding performance of a communications device on a receive end after receiving the bit sequence is improved, a decoding success rate is enhanced, and a quantity of retransmission times is further reduced.
1. A method of rate matching for a low-density parity-check (LDPC) code in a communications system, the method comprising:
obtaining a starting position k 0 in a circular buffer of length N CB for determining an output bit sequence,
wherein the circular buffer comprises an encoded bit sequence D of length K D or N CB bits of the encoded bit sequence D is obtained by encoding a bit sequence of length K based on an low-density parity-check (LDPC) matrix,
wherein for the starting position k 0 is each possible value {p 0 , p 1 , p 2 , . . . , p k max −1 } is less than N CB , k max is an integer greater than or equal to 4, and at least one value p k satisfies expressions (1) |p k −p k−1 | is different from |p k+1 −p k | and (2) 0<k<k max −1; and
outputting the output bit sequence, wherein the output bit sequence comprising E output bits starting from the starting position k 0 in the circular buffer, and each output bit is not a filler bit.
2. The method according to claim 1 , wherein p 0 =0.
3. The method according to claim 1 , wherein p 0 <p 1 <p 2 <p 3 and (p 1 −p 0 )>(p 2 −p 1 ).
4. The method according to claim 3 , wherein k max =4, N CB ≥K D , k>0, and p k ≥(p 0 +K).
5. The method according to claim 3 , wherein k max =4, N CB <K D , k>0, and
p
k
≥
(
p
0
+
K
·
⌈
N
CB
K
D
⌉
)
.
6. The method according to claim 1 , wherein p k =l k ·r, and l k is a positive integer and k>0, r is a quantity of bits comprised in a unit bit segment in the circular buffer, and r is an integer greater than 0.
7. The method according to claim 6 , wherein r=z and z is a lifting factor of the LDPC matrix.
8. The method according to claim 1 , wherein obtaining the starting position k 0 comprises:
obtaining the starting position k 0 based on either one of the following: (a) a starting position number of a redundancy version rv idx or (b) a parameter of a starting position number of a redundancy version rv idx .
9. The method according to claim 8 , wherein the starting position number of the redundancy version rv idx is obtained by using signaling or based on a sequence of starting position numbers of redundancy versions.
10. The method according to claim 9 , wherein the sequence of starting position numbers of redundancy versions is read from a memory.
11. A communications apparatus comprising:
a processor; and
a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions which, when executed by the processor, cause the processor to perform operations comprising:
obtaining a starting position k 0 in a circular buffer of length N CB for determining an output bit sequence,
wherein the circular buffer comprises an encoded bit sequence D of length K D or N CB bits and the encoded bit sequence D is obtained by encoding a bit sequence of the length K based on a low-density parity-check (LDPC) matrix, and
wherein for the starting position k 0 is, each possible value {p 0 , p 1 , p 2 , . . . , p k max −1 } is less than N CB , k max is an integer greater than or equal to 4, and at least one of the values p k satisfies expressions (1) |p k −p k−1 | is different from |p k+1 −p k | and (2) 0<k<k max −1; and
outputting an output bit sequence comprising E output bits, starting from the starting position k 0 in the circular buffer, and each of the E output bits is not a filler bit.
12. The communications apparatus according to claim 11 , wherein p 0 =0.
13. The communications apparatus according to claim 11 , wherein p 0 <p 1 <p 2 <p 3 and (p 1 −p 0 )>(p 2 −p 1 ).
14. The communications apparatus according to claim 13 , wherein k max =4, N CB ≥K D , k>0, and p k ≥(p 0 +K).
15. The communications apparatus according to claim 13 , wherein k max =4, N CB <K D , k>0, and
p
k
≥
(
p
0
+
K
·
⌈
N
CB
K
D
⌉
)
.
16. The communications apparatus according to claim 11 , wherein p k =l k ·r, and l k is a positive integer, k>0, and r is a quantity of bits comprised in a unit bit segment in the circular buffer, and r is an integer greater than 0.
17. The communications apparatus to claim 16 , wherein r=z and z is a lifting factor of the LDPC matrix.
18. The communications apparatus according to claim 11 , wherein the operations further comprise:
obtaining the starting position k 0 based on either one of the following: (a) a starting position number of a redundancy version rv idx or (b) a parameter of a starting position number of a redundancy version rv idx .
19. The communications apparatus according to claim 18 , wherein the starting position number of the redundancy version rv idx is obtained by using signaling or based on a sequence of starting position numbers of redundancy versions.
20. The communications apparatus according to claim 19 , wherein the sequence of starting position numbers of redundancy versions is read from a memory.
21. A non-transitory computer readable storage medium comprising an instruction stored thereon which, when run on a computer, cause the computer to perform operations comprising:
obtaining a starting position k 0 in a circular buffer of length N CB for determining an output bit sequence,
wherein the circular buffer comprises an encoded bit sequence D of length K D or N CB bits of the encoded bit sequence D obtained by encoding a bit sequence of length K based on a low-density parity-check (LDPC) matrix, and
wherein for the starting position k 0 is, each possible value {p 0 , p 1 , p 2 , . . . , p k max −1 } is less than N CB , k max is an integer greater than or equal to 4, and at least one value p k satisfies expressions (1) |p k −p k−1 | different from |p k+1 −p k | and (2) 0<k<k max −1; and
outputting the output bit sequence, wherein the output bit sequence comprising E output bits starting from the starting position k 0 in the circular buffer, and each output bit is not a filler bit.
22. The computer readable storage medium according to claim 21 , wherein p 0 <p 1 <p 2 <p 3 and (p 1 −p 0 )>(p 2 −p 1 ).
23. The computer readable storage medium according to claim 21 , wherein p k =l k ·r, and l k is a positive integer, k>0 and r is a quantity of bits comprised in a unit bit segment in the buffer sequence W, and r is an integer greater than 0.
24. The computer readable storage medium according to claim 23 , wherein r=z and z is a lifting factor of the LDPC matrix.