Rate matching method and apparatus for polar code
Provided is a rate matching method and device for a Polar code. The method includes: concatenating K information bits and (N−K) frozen bits to generate a bit sequence of N bits, and encoding the bit sequence of N bits by means of a Polar code encoder with a generator matrix of size N×N to generate an initial bit sequence {S 0 , S 1 , . . . , S N−1 } of N bits, where K and N are both positive integers and K is less than or equal to N; dividing a circular buffer into q parts, selecting bits from the initial bit sequence {S 0 , S 1 , . . . , S N−1 } in a non-repeated manner, and writing the bits into the q parts of the circular buffer according to a predefined rule, where q=1, 2, 3 or 4; and sequentially selecting a bit sequence of a specified length from a predefined starting position in a bit sequence in the circular buffer and taking the bit sequence of the specified length as a bit sequence to be transmitted.
1. A data transmission method, comprising:
obtaining an encoded bit sequence by encoding a bit sequence using a Polar code encoding;
writing the encoded bit sequence into a circular buffer;
sequentially selecting a bit sequence of a specified length from the circular buffer, and
transmitting a bit sequence based on the bit sequence of the specified length,
wherein responsive to a code rate of the Polar code encoder is less than or equal to a predefined threshold, the bit sequence of the specified length is sequentially selected starting from a position of P0=N−M in the circular buffer, wherein P0 represents a position index of the encoded bit sequence in the circular buffer, M is a length of the bit sequence that is transmitted, and N is a length of the encoded bit sequence; and
responsive to the code rate of the Polar code encoding being greater than the predefined threshold, the bit sequence of the specified length is sequentially selected starting from a starting bit position of the encoded bit sequence in the circular buffer.
2. The method of claim 1 , wherein the writing the encoded bits into the circular buffer comprises:
writing the encoded bits into the circular buffer based on a predefined rule, wherein the predefined rule is determined by a one-to-one mapping interleaving function f(n), wherein n=0, 1, . . . , N−1, f(n)=0, 1, . . . , N−1, n is a bit position index in the initial bit sequence, and f(n) is a position index in the circular buffer.
3. The method of claim 1 , wherein the sequentially selecting the bit sequence of the specified length from the circular buffer comprises:
sequentially selecting bits in an ascending or descending order of indexes starting from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or starting from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold,
reading from the position of P0=N−N in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, to a first end of the encoded bit sequence in the circular buffer, and
continuing the reading from a second end of the encoded bit sequence in the circular buffer until the bit sequence of the specified length is read.
4. The method of claim 1 , further comprising, responsive to a code rate of the Polar code encoding being greater than the predefined threshold, sequentially selecting bits in an ascending order of indexes starting from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or starting from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, reading from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, to a first end of the encoded bit sequence in the circular buffer, and continuing the reading from a second end of the encoded bit sequence in the circular buffer until the bit sequence of the specified length is read.
5. An apparatus for data transmission, comprising:
a processor; and
a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor cause the processor to:
obtaining an encoded bit sequency by encoding a bit sequence using a Polar code encoding;
write the encoded bit sequence into a circular buffer;
sequentially selected a bit sequence of a specified length from the circular buffer; and
transmitting a bit sequence based on the bit sequence of the specified length,
wherein responsive to a code rate of the Polar code encoding being less than or equal to a predefined threhsold, the bit sequence of the specified length is sequentially selected starting from a position of P0=N−M in the circular buffer, wherein P0 represents a position index of the encoded bit sequence in the circular buffer, M is a length of the bit sequence that is transmitted, and N is a length of the encoded bit sequence; and
responsive to the code rate of the Polar code encoding being greater than the predefined threshold, the bit sequence of the specfied length is sequentially selected starting from a starting bit position of the encoded bit sequence in the circular buffer.
6. The apparatus of claim 5 , wherein writing the encoded bit sequence into the circular buffer comprises:
writing the encoded bit sequence into the circular buffer based on a predefined rule, wherein the predefined rule is determined by a one-to-one mapping interleaving function f(n), wherein n=0, 1, . . . , N−1, f(n)=0, 1, . . . , N−1, n is a bit position index in the initial bit sequence, and f(n) is a position index in the circular buffer.
7. The apparatus of claim 5 , wherein the instructions upon execution by the processor further cause the processor, as part of sequentially selecting the bit sequence of the specified length from the bit sequence in the circular buffer, to:
sequentially select bits in an ascending order of indexes starting from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or starting from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold,
read from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, to a first end of the encoded bit sequence in the circular buffer, and
continue to read from a second end of the encoded bit sequence in the circular buffer until the bit sequence of the specified length is read.
8. The apparatus of claim 5 , further comprising, responsive to a code rate of the Polar code encoding being greater than the predefined threshold, sequentially selecting bits in an ascending order of indexes starting from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or starting from the starting bit position of the encode bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, reading from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, to a first end of the encoded bit sequence in the circular buffer, and continuing the reading from a second end of the encoded bit sequence in the circular buffer until the bit sequence of the specified length is read.
9. A non-transitory tangible computer-readable storage medium embodying program code executable by a computing system, the program code comprising:
instructions for obtaining an encoded bit sequencey by encoding a bit sequence using a Polar code encoding;
instructions for writing the encoded bit sequence into a circular buffer;
instructions for sequentially selecting a bit sequence of a specified length from the circular buffer; and
instructions for transmitting a bit sequence based on the bit sequence of the specified length,
wherein responsive to a code rate of the Polar code encoding being less than or equal to a predefined threshold, the bit sequence of the specified length is sequentially selected starting from a position of P0=N−M in the circular buffer, wherein P0 represents a position index of the encoded bit sequence in the circular buffer, M is a length of the bit sequence that is transmitted, and N is a length of the encoded bit sequence; and
responsive to the code rate of the Polar code encoding being greater than the predefined threshold, the bit sequence of the specified length is sequentially selected starting from a starting bit position of the encoded bit sequence in the circular buffer.
10. The non-transitory tangible computer-readable storage medium of claim 9 , wherein the instructions for writing the encoded bits into the circular buffer comprises:
instructions for writing the encoded bits into the circular buffer based on a predefined rule, wherein the predefined rule is determined by a one-to-one mapping interleaving function f(n), wherein n=0, 1, . . . , N−1, f(n)=0, 1, . . . , N−1, n is a bit position index in the encoded bit sequence, and f(n) is a position index in the circular buffer.
11. The non-transitory tangible computer-readable storage medium of claim 9 , wherein the instructions for sequentially selecting the bit sequence of the specified length from the bit sequence in the circular buffer comprises:
instructions for sequentially selecting bits in an ascending order of indexes starting from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or starting from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold;
instructions for reading from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, to a first end of the encoded bit sequence in the circular buffer; and
instructions for continuing the reading from a second end of the encoded bit sequence in the circular buffer until the bit sequence of the specified length is read.
12. The non-transitory tangible computer-readable storage medium of claim 9 , further comprising, responsive to a code rate of the Polar code encoding being greater than the predefined threshold, sequentially selecting bits in an ascending order of indexes starting from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or starting from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, reading from the position of P0=N−M in the circular buffer responsive to the code rate of the Polar code encoding being less than or equal to the predefined threshold, or from the starting bit position of the encoded bit sequence in the circular buffer responsive to the code rate of the Polar code encoding being greater than the predefined threshold, to a first end of the encoded bit sequence in the circular buffer, and continuing the reading from a second end of the encoded bit sequence in the circular buffer until the bit sequence of the specified length is read.