Research And Improvement On Polar Code Based On SC

Polar code is a type of channel code that has been proven to achieve channel capacity.It has low complexity in coding and decoding,and has low error leveling.Polar code has great value and significance,and become one of the research focuses of channel code.In this paper,the encoding and decoding methods of polar code are studied in depth,for example,Successive Cancellation(SC)decoding algorithm of polar code and the Successive Cancellation List(SCL)decoding algorithm.SC decoding algorithm has short decoding time delay,but it has poor performance in high signal-to-noise ratio.SCL secoding algorithm has good performance in bit error rate,but the decoding time delay is large.In view of the existing problems,this paper proposes the improvement based on the original Algorithm,the main work is as follows:(1)In order to increase the correct rate of SCL Algorithm,this paper proposes a Position-Aided SCL(PA-SCL)decoding algorithm,which generates a check code according to the position of "1" in the information sequence,the decoding performance of the algorithm is about 10% better than SCL Algorithm.(2)In order to reduce the bit error rate(Ber)of the CA-SCL Algorithm at high signal to noise ratio(SNR),proposed Enhance Parity and CRC Aided Successive Cancellation List(EP-CA-SCL)decoding algorithm,The enhanced parity check will be performed on the sequence that passed the CRC check.this method does not increase the complexity,but it occupies a part of the information bits,and it is about 8% better than the algorithm of CA-SCL decoding.(3)For the selection of the minimum likelihood ratio in the SFSC decoding algorithm,this paper proposes a weighted multi-bit SFSC decoding algorithm.In the selection of unreliable information bits,the likelihood ratio of the information bits is combined with the channel capacity.In the decoding method,a weighted multi-bit bite-flip is used for decoding.When the code length is 128(R=0.5)and the number of unreliable information is 7,the simulation is carried out.When the error block rate is 0.002,the algorithm improves the decoding of the SFSC by about 6.7%.This paper proposes that the three decoding algorithms have different degrees of improvement in the block error rate.The PA-SCL decoding algorithm and EP-CA-SCL decoding algorithm are basically the same as the original algorithm in decoding complexity.The time complexity of the weighted multi-bit SFSC decoding algorithm is not good at low signal-to-noise ratio,but the decoding complexity at high signal-to-noise ratio is basically consistent with the original algorithm.