Research And Optimization Of Polar Code Encoding And Decoding Technology

Channel coding is an important technical means used to improve the anti-interference ability in data transmission.Polar code is a new channel coding technology recently proposed.It is the first coding scheme that has been theoretically proved to be capable of reaching the Shannon capacity,and has a regular construction method.Since the polar code was proposed by Arikan systematically in 2009,it has attracted a lot of attention at home and abroad due to its excellent bit error rate performance and low coding and decoding complexity,and it has become the control channel coding scheme in the 5G communication enhanced mobile broadband scenario.The main research contents of this thesis are as follows:1.The basic concept and theoretical basis of polar codes are studied,the channel polarization theory and the coding process of polar codes are described,and two common polar code decoding algorithms are introduced in detail.2.To reduce the high complexity of successive cancellation list(SCL)decoding,we propose an improved SCL algorithm with lower complexity for partial path extension and segmented check pruning(PE-SCP-SCL).First,the reliability of the polarized channel itself is used as a basis for measuring whether the decoding result is reliable.If it is reliable enough,a hard decision is made directly,otherwise the path expansion is performed,and the parameter a is introduced into the algorithm to balance the complexity and The performance,so that policy needs in different application scenarios can be met;on the other hand,several parity check points are introduced to perform segmented check during the decoding process,and if the check fails,the current path is directly rejected.Theoretical analysis proves that the extra errors introduced by the check pruning operation are almost negligible,which verifies the rationality of the operation.Numerical simulations also verify that the proposed algorithm can significantly reduce the complexity of decoding with trivial loss of error rate.3.Low latency polar coded modulation schemes over non-coherent MIMO are proposed in this thesis.First,the basic principle of polar coded modulation in non-coherent MIMO channels is studied.Considering that the demodulation complexity of non-coherent MIMO is already high,and the signal receiving structure of multi-level coded modulation has the characteristics of high time complexity and high latency,which is not good for practical application,therefore two solutions are proposed in order to solve the problem of excessive system latency.One is a bit interleaved coded modulation scheme that uses chunked polar code transmission,and the other one is to optimize the multi-stage decoding structure of multi-level coded modulation so that receiver latency can be reduced.Finally,the complexity analysis and BER performance simulation results of each scheme are given.