The Application Of Improved LDPC Encoding And Decoding Algorithms In LTE-A System

LTE-A system is one of the main technologies supposed to be used for4G.It is definedas a smooth evolution for compatibility under the requirements of the IMT-Advanced. Thestandard of requirement in LTE is not only the technology of channel coding can support1Gbit/s rate transmission, and maintain the compatibility of R8LTE, but allow to select anduse other modulation coding technologies in new frequency range and applicationcontext.With the increase of the LET-A’s bandwidth and data rate,data block is even larger,sothe new channel coding (LDPC codes) has been considered; it has a systematic majorizationdesign produces, and has much more approach distinction error correcting capability andlower error floor. Besides, it has the characteristic of against burst error, which do not need tointroduce mixed device, and prevent intention delay. The merit of LDPC codes are verysuitable for realize in the future mobile communication system, and reveal a great applicationprospect in the wireless mobile communication of poor channel conditions.Firstly, the article reviews the trend of the evolution of LTE-A system and analyzes theresearch situation and development prospects of LDPC codes in the meantime.Based on theprinciples of LDPC codes,the article talks about the structure of the codes and the arithmeticof complied codes. in the meantime,it stimulates the function of LDPC by MATLAB,andanalyses the factors influcing it. Thereafter, according to Potevio mother code structure,LDPC code is created which has a different code length and a lower bit-rate,indicating thatthese LDPC codes are compatible with the existing LTE-channel coding technique.Theselection scheme of LTE-A system is clarified,and the way to expand low rate LDPC codesare introduced in detail, making the improvement of the two expanded LDPC codes.Finally to increase the function of the LDPC codes,and lower the complexity,the articleintroduced a way to interpret codes by normalizing and drifting Min-sum arithmetic.Thisarithmetic not only lower the complexity of arithmetic,but also maintain the good function ofLDPC by combining the normalized Min-sum and the advantages of it.As a result, it isextremely closed to BP arithmetic.In the end,we choose the best QC-LDPC technique andnormalized Min-sum technique to build LTE-PDSCH channel.Through the compare of thefalse rates of Turbo and LDPC in LTE-PDSCH channel,we can have the conclusion thatLDPC is better than Turbo.The article found another suitable way to interpret LDPC codes inLTE-A system,eliminating floor effect,increasing efficiency,and lowering consumption.