Concatenation of SC-LDGM Codes with Outer BCH Codes

Systematic convolutional low density generator matrix (SC-LDGM) codes are a class of codes with flexible construction and predictable performance. However, the SC-LDGM codes suffer from error floors. In this paper, we propose to lower down the error floors of the SC-LDGM codes by the use of concatenated codes with the outer Bose-Chaudhuri-Hocquenghem (BCH) codes. Performance bounds are derived for the proposed concatenated codes based on genie-aided (GA) bounds on the inner SC-LDGM codes. As a byproduct, we show that the outer BCH codes can also be used as a constraint to stop early the iterative decoding. The simulation results confirm our analysis.