Research On Polar Codes Performance Improvement Based On Concatenation

With the development of the informati,the demand for information has gradually increased.5G completed its first phase of full function standardization in June 2018.As a new type of advanced channel coding for near-capacity transmission,polarization code is used as control channel coding standard in 5G eMBB scenario.Nevertheless,there are still many shortcomings in the medium and short code length polarization codes.According to the polarization characteristics of polarization codes,when the code length tends to be infinite,the channel polarization is almost complete,so the performance of polarization codes on long codes is superior;because of the incomplete polarization of channels,the performance of coding and decoding of short and medium codes is slightly less than that of long codes,and the error correction ability is worse than that of codewords that have been well studied by similar technologies.In eMBB scenarios,short and medium code length polarization codes are used.Therefore,the performance improvement of short and medium code length polarization codes is the focus of current research.In order to solve the problem of poor performance of polarization codes under medium and short code length,this paper chooses the concatenated scheme of polarization codes as the research subject,and improves the concatenated polarization codes from two aspects: concatenated structure and decoding algorithm.In terms of structure,multiple rate allocation schemes and interrelated bit interleaving schemes are proposed.Multiple bit rate allocation is to estimate the channel reliability and obtain the reliability parameters.RS codes with multiple bit rates are selected as external codes,and RS codes with different bit rates are allocated to different reliability channels under the condition of guaranteeing the overall bit rate unchanged.For channels with poor reliability,RS codes with strong error correction ability,i.e.low bit rate RS codes,are allocated to them,whereas high bit rate RS codes are allocated to them.Through the analysis of the causes of error bits and error modes,according to the characteristics of polarization code errors,it is found that there are association errors among bits.Based on the traditional interleaving scheme,an interleaving scheme based on Association bits is proposed,which disperses the associated error bits into different symbols to make the external code perform better.Error correction.In terms of decoding algorithm,an interactive decoding algorithm and a soft decoding algorithm are proposed.Because the error in the previous decision of polarization code will increase the probability of error in the later decision result,that is,the phenomenon of error transmission,according to this characteristic,an interactive decoding scheme is proposed.In the decoding process of polarization codes,each decision bit is first corrected by RS code,and then the next decision bit is decoded by polarization code.On this basis,the outer code performance of concatenated codes is further optimized.Because the performance of soft decision decoding is better than that of hard decision decoding,the original RS hard decision decoding is replaced by RS soft decoding algorithm.By making full use of soft information and combining with interactive decoding,the performance of concatenated codes is further improved.Simulation results show that the above schemes can effectively improve the performance of concatenated codes.