Decoding method and decoding device for polar code cascaded with cyclic redundancy check

Abstract

The embodiments of the present invention provide a decoding method and a decoding device for a polar code cascaded with CRC. The decoding method includes: performing SC-List decoding on a Polar code according to the number of survival paths L to obtain L survival paths, where L is a positive integer; performing cyclic redundancy check on the L survival paths respectively; and increasing the number of survival paths when all the L survival paths fail to pass the cyclic redundancy check, and acquiring a decoding result of the Polar code according to the increased number of survival paths. In the embodiments of the present invention, the path number of survival paths is adjusted according to a result of the cyclic redundancy check, so as to output paths as much as possible, where the output paths can pass the cyclic redundancy check, thereby improving decoding performance.

What is claimed is: 
     
       1. A decoding method for decoding a Polar code cascaded with cyclic redundancy check CRC, performed by a decoding device, the method comprising:
 receiving a Polar code, wherein the Polar code is obtained by encoding information bits;  
 performing, according to a number of survival paths L, a successive-cancellation-list (SC-List) decoding on a the Polar code, to obtain L survival paths, wherein L is a positive integer; 
 performing a cyclic redundancy check on each of the L survival paths respectively; 
 increasing the number of survival paths by ΔL in response to all the L survival paths failing to pass the cyclic redundancy check, wherein ΔL is a positive integer; and 
 acquiring a decoding result of the Polar code according to the increased number of survival paths L+ΔL; and 
 outputting the decoding result. 
 
     
     
       2. The method according to  claim 1 , wherein acquiring the decoding result of the Polar code according to the increased number of survival paths, L+ΔL comprises:
 if the increased number of survival paths is less than or equal to a threshold value, re-executing the method according to the increased number of survival paths to acquire the decoding result of the Polar code; or 
 if the increased number of survival paths L+ΔL is greater than a threshold value, outputting a survival path with a greatest probability value among the L+ΔL survival paths as the decoding result of the Polar code. 
 
     
     
       3. The method according to  claim 1 , wherein increasing the number of survival paths by ΔL comprises:
 increasing the number of survival paths L by m, wherein m is a positive integer, or 
 multiplying the number of survival paths L by n, wherein n is greater than 1. 
 
     
     
       4. The method according to  claim 1 , further comprising:
 if one or multiple of the L survival paths pass the cyclic redundancy check, outputting a survival path with a greatest probability value of the one or multiple of survival paths as the decoding result of the Polar code. 
 
     
     
       5. The method according to  claim 1 , further comprising:
 setting an initial value of the number of survival paths according to a demand for decoding complexity or a demand for decoding performance. 
 
     
     
       6. A decoding device for decoding a Polar code cascaded with cyclic redundancy check CRC, the device comprising:
 a processor and a memory coupled to the processor; 
 wherein, by executing program codes stored in the memory, the processor is configured to:  
 a decoder, configured to perform, according to a number of survival paths L, a successive-cancellation-list (SC-List) decoding on a the Polar code to obtain L survival paths, wherein the Polar code is obtained by encoding information bits, and wherein L is a positive integer; 
 a checker, configured to perform cyclic redundancy check respectively on each of the L survival paths that are obtained by the decoder; and 
 a selector, configured to increase the number of survival paths by ΔL in response to all the L survival paths failing to pass the cyclic redundancy check and, wherein ΔL is a positive integer;  
 acquire a decoding result of the Polar code according to the increased number of survival paths L+ΔL; and 
 output the decoding result. 
 
     
     
       7. The device according to  claim 6 , wherein the selector processor is configured to output the increased number of survival paths to the decoder when the increased number of survival paths is less than or equal to a threshold value, so that the decoder performs the SC-List decoding on the Polar code again according to the increased number of survival paths; or output a survival path with a greatest probability value among the L+ΔL survival paths as the decoding result of the Polar code when the increased number of survival paths L+ΔL is greater than a threshold value. 
     
     
       8. The device according to  claim 6 , wherein in increasing the number of survival paths by ΔL, the selector processor is configured to: 
 increase the number of survival paths L by m, wherein m is a positive integer, or 
 multiply the number of survival paths L by n, wherein n is greater than 1. 
 
     
     
       9. The device according to  claim 6 , wherein the selector processor is further configured to, if one or multiple of the L survival paths pass the cyclic redundancy check, output a survival path with a greatest probability value of the one or multiple of survival paths as the decoding result of the Polar code. 
     
     
       10. The device according to  claim 6 , wherein the decoder  processor is further configured to set an initial value of the number of survival paths according to a demand for decoding complexity or a demand for decoding performance. 
     
     
       11. A method, performed by an encoding device, comprising:
 obtaining a plurality of non-frozen bits;   performing a cyclic redundancy check (CRC) on the non-frozen bits, to obtain CRC checked bits;   adding one or more frozen bits to the CRC checked bits;   performing a polar encoding process on the CRC checked bits and the frozen bits, to obtain a polar code; and   outputting the polar code.   
     
     
       12. The encoding method according to claim 11, wherein the polar encoding process is expressed as:
   x 1   N =u 1   N G N,      wherein x 1   N  is the outputting polar code, G N,  is a generator matrix for the polar code, and u 1   N  are inputting bits, wherein the inputting bits include the CRC checked bits and the frozen bits.   
     
     
       13. The encoding method according to claim 12, wherein a length of the polar code is N, N=2{circumflex over ( )}n, and n≥0. 
     
     
       14. The encoding method according to claim 11, wherein the polar code is configured for decoding using CRC check of one or more of L survival paths, wherein L is a positive integer. 
     
     
       15. The encoding method according to claim 11, wherein the polar code is configured for successive-cancellation-list (SC-List) decoding using CRC check of one or more of L survival paths. 
     
     
       16. The encoding method according to claim 11, wherein the polar code is configured for successive-cancellation-list (SC-List) decoding using a number L of survival paths adapted according to a result of CRC check of the survival paths. 
     
     
       17. An encoding device, comprising a processor and a memory storing program codes for execution by the processor, wherein the program codes, when executed by the processor, cause the encoding device to:
 obtain a plurality of non-frozen bits;   perform a cyclic redundancy check (CRC) on the non-frozen bits, to obtain CRC checked bits;   add one or more frozen bits to the CRC checked bits;   perform a polar encoding process on the CRC checked bits and the frozen bits to obtain a polar code; and   output the polar code.   
     
     
       18. The encoding device according to claim 17, wherein the polar encoding process is expressed as:
   x 1   N =u 1   N G N,     wherein x 1   N  is the outputting polar code, G N,  is a generator matrix for the polar code, and u 1   N  are inputting bits, wherein the inputting bits include the CRC checked bits and the frozen bits.   
     
     
       19. The encoding device according to claim 18, wherein a length of the polar code is N, N=2{circumflex over ( )}n, and n≥0. 
     
     
       20. The encoding device according to claim 17, wherein the polar code is configured for decoding using CRC check of one or more of L survival paths, wherein L is a positive integer. 
     
     
       21. The encoding device according to claim 17, wherein the polar code is configured for successive-cancellation-list (SC-List) decoding using CRC check of one or more of L survival paths. 
     
     
       22. The encoding device according to claim 17, wherein the polar code is configured for successive-cancellation-list (SC-List) decoding using a number L of survival paths adapted according to a result of CRC check of the survival paths. 
     
     
       23. The encoding device according to claim 17, wherein the encoding device is a base station or a terminal device. 
     
     
       24. A non-transitory computer-readable storage medium storing program codes which, when executed, cause an encoding device to:
 obtain a plurality of non-frozen bits;   perform a cyclic redundancy check (CRC) on the non-frozen bits, to obtain CRC checked bits;   add one or more frozen bits to the CRC checked bits;   perform a polar encoding process on the CRC checked bits and the frozen bits to obtain a polar code; and   output the polar code.   
     
     
       25. The non-transitory computer-readable storage medium according to claim 24, wherein the polar encoding process is expressed as:
   x 1   N =u 1   N G N,      wherein x 1   N  is the outputting polar code, G N,  is a generator matrix for the polar code, and u 1   N  are inputting bits, wherein the inputting bits include the CRC checked bits and the frozen bits.   
     
     
       26. The non-transitory computer-readable storage medium according to claim 25, wherein a length of the polar code is N, N=2{circumflex over ( )}n, and n≥0. 
     
     
       27. The non-transitory computer-readable storage medium according to claim 24, wherein the polar code is configured for decoding using CRC check of one or more of L survival paths, wherein L is a positive integer. 
     
     
       28. The non-transitory computer-readable storage medium according to claim 24, wherein the polar code is configured for successive-cancellation-list (SC-List) decoding using CRC check of one or more of L survival paths. 
     
     
       29. The non-transitory computer-readable storage medium according to claim 24, wherein the polar code is configured for successive-cancellation-list (SC-List) decoding using a number L of survival paths adapted according to a result of CRC check of the survival paths.