Concatenated Codes for Deletion Channels

We design concatenated codes suitable for the deletion channel. The inner code is a combination of a single deletion correcting Varhamov-Tennengolts block code and a marker code. The outer code is a low-density parity-check (LDPC) code. The inner decoder detects the synchronizing points in the received symbol sequence and feeds the outer LDPC decoder with soft information. Our simulation results with regular LDPC outer codes demonstrate that bit error rates of 10^{-6} can be obtained at rate 0.21 when the probability of deletion is 8%