Research On Polar-staircase Coding Scheme

As a great breakthrough in coding theory in recent years,polar codes have been proved that it can achieve the capacity of binary-discrete memoryless channel(B-DMC)with low coding and decoding complexity.It has received great attention from the society.The fifth generation communication mobile communication system(5G)has selected it as the coding scheme of the Enhanced Mobile Broadband(eMBB)control channel.However,when the code length is limited,the subchannel of the polar codes cannot be completely polarized.Then part of the information is transmitted on the subchannel with incomplete polarization,resulting in an increase in the bit error rate.In order to improve the performance of polar codes with finite length,this paper studies the traditional concatenated scheme.And then we innovatively design a concatenated structure called polar-staircase codes.We design the corresponding parallel soft output iterative decoding algorithm for the polar-staircase codes.In order to further improve the decoding performance,we combine the successive cancellation list(SCL)decoding algorithm with cyclic redundancy check(CRC).And we design an improved CRC-soft SCL decoding algorithm.We also analyze the upper and lower bounds of the decoding performance of polar-staircase codes.The main research work is as follows:Firstly,we review the basic phenomenon of the channel polarization.The construction of systematic polar codes is analyzed.At the same time we research and analyze Belief Propagation(BP)decoding algorithm and soft cancellation(SCAN)decoding algorithm.In order to improve the performance of polar codes with finite length,we concatenate low density parity check(LDPC)codes and BCH codes with polar codes.We can conclude that the concatenation can get better decoding performance especially with soft decoding algorithm,Then,we choose systematic polar codes to concatenate the information bits transmitted on the subchannel with poor reliability.Based on the staircase codes,we propose the polar-staircase coding scheme.The scheme concatenates the information bits the subchannel with poor reliability.According to the BP decoding algorithm and SCAN decoding algorithm of the polar codes,we respectively design the parallel soft output iterative decoding algorithm for the polar-staircase codes.The simulation shows that the polar-staircase codes can effectively improve the decoding performance of the polar codes with finite length.Finally,a soft SCL(SSCL)decoding algorithm is proposed based on the conventional SCL decoding algorithm to get better performance.Also we combine the SSCL decoding with the CRC check codes and get an improved CRC-SSCL decoding algorithm.During the iterative decoding iteration process,we can use CRC check code to check that whether the sequence is correctly decoded.If it is correctly decoded,we treat the bits in it as the known imformation.By the check operation,we can improve the decoding performance.Also we theoretically analyze the upper and lower bounds of polar-staircase codes.Simulations shows the outperform performance of this improved algorithm.And we can see that the simulation results are also between the upper and lower bounds.