Research On LDPC Code And Its Application In Key Distribution

In this information age,our lives are changing at all times.Whether it is daily ordinary people's work,study,or the country's political,economic,cultural and so rely on the reliable transmission of information.Especially in the past few years,the rapid development of communication technology has been widely penetrated to our side,greatly changed our way of life.Since 1948,Shannon,founder of the theory of information,published the Mathematical Theory of Communication.Until now,channel coding has gone through nearly 70 years of history and gradually gained a place in the field of communications and became an independent discipline.In the field of channel coding technology,there is a very hot code,that is,low density parity check code,the English name Low density Parity-check Code,is a close to Shannon limit linear block code,in the research process and practical application also reflects LDPC code has a very good performance,such as parallel decoding,coding and decoding of the lower complexity,real-time and so good.In recent years,with the continuous attention and deep understanding of LDPC code,from the LDPC code coding,parity matrix structure and decoding methods to study,as well as in other applications,people have accumulated a lot of rich Experience,but also made a lot of valuable results.It can be said that the study of LDPC code can not only contribute to human science,but also in practical applications to bring great economic value.Based on the theory of LDPC codes,this paper introduces the concept of LDPC codes,coding and decoding principle,quasi-cyclic LDPC codes,perforated LDPC codes,and so on.In this paper,after reading the relevant literature and combining with previous research work,An application based on quasi-cyclic perforated LDPC codes in quantum key distribution can be made from the following parts:The first part introduces the digital communication system and gives its model structure.Then it introduces the concept of error correction code and the related knowledge of error correction principle.Finally,we introduce a good code of error correction code is LDPC code,the specific content we later detailed,in this brief to introduce the LDPC code,such as its research status,research significance.The second chapter mainly elaborates the definition of LDPC and its basic concept,and then we introduce the coding methods of commonly used LDPC codes,such as traditional coding algorithms,coding methods based on approximate triangular matrix,and so on.Finally,several decoding algorithms of LDPC codes are discussed in detail,including confidence propagation algorithm,logarithmic belief propagation algorithm,minimum algorithm and so on.The third chapter introduces the construction of two kinds of LDPC codes,that is,quasi-cyclic LDPC codes and punching LDPC codes.In the LDPC code has a very important point is the check matrix H,H structure is good or bad regardless of the encoding of LDPC code,or itsdecoding plays a vital role,so the construction of a good LDPC code naturally It is very important.At the end of this chapter,the simulation of these two kinds of LDPC codes is made.The simulation results show that the structure of LDPC codes can affect the performance of LDPC codes.The fourth chapter firstly introduced the background of quantum communication system.Then,on the basis of this,we propose a scheme of quantum key distribution based on Punctured QC-LDPC code,which has certain advantages over the previous scheme.Not only do we give a specific process,but also the results are analyzed.The specific content will be described in detail later,here a brief description of this.The details will be described later,Here is a brief description of this.In the last chapter,we make a brief summary of the previous content and present a vision for future research.