Accumulate-turbo codes for redundant data

Accumulate-turbo codes are proposed for use in channel coding of data that contains redundancy. Accumulate-turbo codes are nonsystematic channel codes that consist of a cascade of an outer accumulator, an interleaver, and an inner turbo code. The outer accumulator acts as a rate one source code, which allows better utilization of redundancy already in the data in channel decoding than in other previously proposed joint source-channel coding methods. Initial simulations performed on independent and identically distributed (i.i.d.) sequences demonstrate performance that is less than 1 dB away from the theoretical limits for different non-uniformities for moderately long blocks. The performance achieved also for relatively short blocks is better than that achieved in recent works that address this problem. Unlike many of the recently proposed approaches, accumulate-turbo codes appear to be very robust to the data non-uniformity, yet, without sacrificing performance.