Concatenated LDGM codes with single decoder

We propose a design criterion for serially concatenated LDGM codes which require a single decoder and a bit-interleaver. The inner LDGM code can be obtained by expanding the rows of the parity check matrix of the outer LDGM code. The resulting codes can be decoded using only the inner LDGM decoder with slight modification. Simulation results show that the performance of the proposed codes is almost the same as that of serially concatenated LDGM code´s using both the inner and the outer decoders.