Optimized turbo codes for delay constrained applications

We present the results of the optimization applied to the design of interleavers for rate-1/n parallel concatenated convolutional codes (PCCC) tailored to specific recursive systematic convolutional (RSC) constituent codes. The emphasis is on low-latency codes associated with interleavers of block length less than or equal to 160. The error floors of the optimized codes are significantly lower than those associated with the use of random interleavers. The distance spectra of the equivalent block codes resulting from trellis termination applied to PCCC are evaluated and used to obtain asymptotic bit error rate (BER) curves for the optimized codes.