Research On The Spinal-polar Interleaved Concatenated Code

Recent years,with the rapid development of mobile Internet,5G has attracted a lot of attention in the field of communication with the characteristics of high reliability,low transmission delay and ultra-high transmission speed.In June 2019,the Ministry of Industry and Information Technology officially issued the license of 5G,which means that China has entered the era of 5G commercial using.Polar code,also known as polarization code,is the first channel coding scheme that theoretically proves to reach shannon limit.With high potential and research value,Polar code has been selected as the short code standard for controlling channel in 5G.However,in the scheme of short or medium code-length,the channel polarization is not perfect,thus the performance of the polarization code is still inferior to other advanced channel coding technologies.In order to make Polar code better applied in 5G,it is feasible to concatenate Polar code with other advanced code to improve performance.This paper select Spinal-Polar concatenated code as the research subject,at the same time,the theoretical analysis and rate allocation scheme are studied,mainly including three aspects: the basic of the Spinal-Polar interleaved concatenated code and the improvement scheme;the bit error rate(BER)upper bound of Spinal-Polar code is derived,and the rate allocation scheme optimization modeling and solving which based on the bit error rate upper bound.Aiming at improving the performance of Polar code with finite length,this paper designs a Spinal-Polar interleaved concatenated code.Proposed in 2011,Spinal code is a kind of pseudo-random rateless code.The high performance makes Spinal code suitable for Polar code concatenated structure.Spinal-Polar code is used to improve the performance of finite length Polar code by means of the error correction ability of Spinal code.In addition,the joint iterative decoding algorithm is proposed to improve the error-derived phenomenon of Polar decoding.According to the characteristics of different reliability of polarization channel,an unequal bit rate allocation scheme is proposed to further improve the bit error rate performance at the same bit rate.In order to reduce the waste of outer code rate,the partial concatenation scheme is designed,which reduces the complexity of coding and decoding.For theoretical analysis,in order to improve the overall framework of Spinal-Polar code and lay a foundation for the design of subsequent high-efficiency schemes,this paper has presented the theoretical derivation with the bit error rate upper bound of Spinal-Polar code.First,bit error rate upper bound for Spinal code in binary symmetric channel(BSC)is deduced from the Chernoff-bound.Secondly,based on the principle of interleaved concatenated structure,the decision probability of maximum log likelihood ratio(LLR)distribution of each subchannel of polarization code is equivalent to the error probability,thus deducing the upper bound of error rate of Spinal-Polar code with finite code length under BSC.Simulation results show that the theoretical upper bound of well characterizes the error bit rate of Spinal-Polar code,and is a strict upper bound.Finally,this paper focuses on optimizing the unequal rate allocation scheme.By establishing an optimization mathematical model,the parameters of the corresponding unequal code rate allocation scheme are solved.Simulation results show that the unequal bit rate allocation scheme solved by the optimization mathematical model can significantly improve the bit error rate performance.