Polarization Code Encoding And Decoding

Polar codes is a new method of channel coding based on channel polarization phenomenon proposed by E.Arikan which can be proved to achieve Shannon limit in the theory and has a lower computational complexity of encoding and decoding which is a major breakthrough in the field of wireless communications and has become one of the highly anticipated research focus in the coding field. This article mainly talks about the study for encoding and decoding algorithms of polar codes and main work is summarized as follows:1、Channel polarization phenomenon is analyzed and the detailed process of channel combining and channel splitting is deduced. The significance of channel polarization in the construction of the polar codes is proved by analyzing the simulation of channel polarization and the channel cutoff frequency.2、The coding principles of polar codes are systematically elaborated. The formation process of the polar codes’generator matrix is deduced and methods of how to select the information bits are summarized. Then focus on simulating and discussing the decoding performance of SC decoding algorithm, BP decoding algorithm and ML decoding algorithm under AWGN channel. It proves that decoding performance becomes better when the length of codes becomes longer and the rate becomes smaller and the iterations become larger and SC decoding algorithm and BP decoding algorithm is more suitable for longer polar codes while ML decoding algorithm for shorter polar codes.3、During constructing poplar codes some channels without polarization are chosen as information bits and this will affect the performance badly. This problem can be solved by combing the least reliable information bits with suitably chosen frozen bits to construct inner block codes which can improve the SC decoding performance. The simulation results shows that improved SC decoding algorithm achieve a significantly lower BER than old.4、The aspects of coding and decoding performance of polar codes are compared with RM codes and LDPC codes. The performance and merit and demerit of these three kinds of channel coding are analyzed via the simulation results of BP decoding algorithm.