Research On The Design Of LDPC Code

LDPC is short for Low Density Parity Check Codes, it has excellent decoding performance, and when the code length is big enough, it can achieve performance very close to the Shannon limit, and even exceeds Turbo codes. Additionally, the decoding complexity is very low and is very suitable for implementation on hardware for parallel computation. For these reasons, it has aroused great interests in researchers, and has bright future for application in digital communication system.As the society develops, the needs for information storage become larger and larger. Along with the explosion of knowledge, the information coming to us every day increases in an explosive way too. And the efficient storage of this information becomes a critical problem.Magnetic storage technology has the advantage of high density, large capacity, high speed and low cost, and plays an important role in information storage area. To satisfy the increase in storage capacity, and raise the storage density as high as possible, the way for disk recording has changed from traditional horizontal storing to vertical storing. However, while increasing the storage capacity, the vertical storage technology also suffers more from noise interference. To insure the reliability of storage, it’s necessary to use the error correcting code technology. Error correcting code technology is firstly used in non-violate storage device such as Nand Flash. For the characteristics of its physical structure, it’s susceptible to errors, and error correcting technology is needed in insure reliability. Hamming code, RS code and BCH code and other coding technologies has already been used in the error correcting system. LDPC code, is becoming the focus of error correcting code research for its high performance and easy for application.In this article, the coding and decoding algorithm and the method to construct parity check matrix are studied, and then a QC-LDPC code of high performance and easy hardware implementation is proposed. Through simulation to the hard disk storage channel in matlab, an assessment on the performance is made. Which proves that the code designed is a good error correcting code and suitable for magnetic channels.