Locality-Improved Repairable Fountain Codes for Distributed Storage Systems

We propose systematic fountain codes over GF (q) with the maximum likelihood (ML) decoding for distributed storage systems (DSS), which is called locality-improved repairable fountain codes (LIRFC). A generator matrix is constructed by entry-wise sampling and row-discarding, where the parameters are carefully determined such that locality is reduced while the ML decoding performance is not degraded. The degree distribution of the proposed codes is represented as a truncated and scaled binomial distribution with an optimized truncation threshold. Compared to the repairable fountain codes (RFC) that have logarithmic locality, the proposed codes achieve 5.97% to 22.44% less average locality than RFC, while having equivalent decoding failure probability and higher availability.