Research On Erasure Code For Disaster Recovery System

Redundancy check mechanism takes an important part in disaster recovery system. We use the mechanisms of complete data replication and Redundant Array of Inexpensive Disks(RAID) in the past, but in recent years the application of erasure code in disaster recovery system has caught worldwide attention. Compare with other mechanism, erasure-correcting codes can save more storage space, enhance fault-tolerant capability and data reliability. Based on the existing result about erasure-correcting technologies, the contribution of this paper is as follow:This paper proposed Extended Progressive Edge-Growth Algorithm for construction of parity check matrix of irregular LDPC codes. By increasing the row weight of parity check matrix, this algorithm can generate irregular LDPC codes with very high code rate. At the same time, by setting the low bound of girth, we can still ensure that the LDPC code has low bit error rate.This paper proposed an arithmetic algorithm based on inequality for Quasi-Cyclic LDPC codes. By searching for its mother matrix, we can get parity check matrix with large girth, and its corresponding QC-LDPC code has a very low bit error rate. Compare with other existing algorithm(e.g. BIBD), with code rate confirmed, the bit error rate of ours is lower.