Average performance of parallel concatenated block codes

A parallel concatenated coding scheme consists of two simple systematic constituent encoders linked by an interleaver. The input bits to the first encoder are scrambled by the interleaver before entering the second encoder. The codeword of the parallel concatenated code consists of the input bits followed by the parity check bits of both encoders. We propose for the first time an analytical solution to the problem of bounding the performance of parallel concatenated block codes, showing the influence of the interleaver length on the parallel code performance