低错误平层LDPC码构造研究-计算机系统结构专业论文.docxVIP

Abstract Low density parity check (LDPC) codes have been shown to achieve remarkable performance which is very close to the Shannon limit, and have attracted a lot of attentation in the channel coding field. Due to the advantage of LDPC codes, such as good distance features, low decoding complexity, they have received great interests in research field and IT field. With the intensive research, LDPC codes have potential applications in the field such as wireless communication, optical network and digital storage. Based on the existing knowledge of LDPC codes, this paper mainly focus on minimum distance, stopping set and error floor of LDPC codes. Some results are obtained and summarized as follow: The basic principle of LDPC codes is illuminated. The principles of coding and decoding for LDPC codes are briefly summarized. Some bounds of LDPC codes’ minimum distance are summarized. Increasing minimum distance of LDPC coeds can improve finding error and correcting error performance of the codes.Based on error impulse method, an algorithm for computing minimum distance of LDPC codes is analyzed intensively. The algorithm can get approximate minimum distance of LDPC codes, and thus estimate the FERs of LDPC codes efficiently, which is approved by simulation. A novel algorithm to eliminate small stopping sets in irregular LDPC codes is researched in detail. By adding several new check nodes and edges which connect the new check nodes with bit nodes form stopping sets, the number of small stopping sets is decreasing efficiently, and thus the error floor is reduced significantly, which is also approved by simulation. Keywords: Low density parity check codes Minimum distance Error impulse Stopping set Error floor 创新性声明 本人声明所呈交的论文是我个人在导师指导下进行的研究工作及取得的研究 成果。尽我所知，除了文中特别加以标注和致谢中所罗列的内容以外，论文中不 包含其他人已经发表或撰写过的研究成果；也不包含为获得西安电子科技大学或 其它教育机构的学位或证书而使用过的材料。与我一同工作的同志对本研究所做 的任何贡献均已在论文中做了明确的说明并表示了谢意。 申请学位论文与资料若有不实之处，本人承担一切相关责任。 本人签名： 日期 关于论文使用授权的说明 本人完全了解西安电子科技大学有关保留和使用学位论文的规定，即：研究 生在校攻读学位期