Polar Codes And Its Application In Wireless Communications

Polar code is a very new error-control channel code.Since polar code have great performance advantages compared with the traditional code,it has quickly become a hot spot of research in communication academia since it was proposed in 2008.Polar code has been mathematically proven to be the only codes that enable to reach the Shannon limit when the code length is infinite.Considering to the requirements of future communication,this paper studies on how polar code satisfies higher standards of communication transmission and its current performances that need to be improved based on principle of channel polarization.The main purpose is to reduce the implementation complexity of encoding and decoding algorithm and get the flexible adaptation of code rate in actual communication.In this paper,we expanded the application range of the polar code,and simplify the calculation and implementation.In this paper,we first introduced the background and history of polar code briefly based on the digital communication and Shannon theory.Next,we explained the basic principle of channel polarization,which contains channel combination and channel splitting.According to this theory of channel polarization,we introduced the encoding and decoding method.Among them,the method of information bit selection and several decoding algorithms are specifically described.Secondly,due to the requirement of computational and spatial complexity,as well as the delay of communication transmission in modern wireless communication,considering the wide application prospect of polar code,this paper proposed an improved method of polar code construction,which has a low complexity based on the structure of multi-CRC check and polarization weight reliability metrics.This method can combine the advantages of the two methods above,reduce the complexity at both encoding and decoding part,and at the same time keep the excellent performance of the polar code.Which makes polar code suitable for the ultra-reliable and low latency communication scenario.Finally,considering that in actual communication,the code rate and length of polar codes are required to be flexible changeable so as to maintain high communication quality.In this regard,researchers have proposed several rate-compatible polar codes,such as punctured polar codes and shortened polar codes.Based on this,we proposed a new kind of rate-compatible polar code,which combines the advantages of the puncturing and shortening and gets a good performance in both low and high code rate.