QPP interleavers selection based on convergence of iterative turbo-decoding process at small block size

In this paper, performance in terms of Bit Error Rate (BER) and Frame Error Rate (FER) of the best quadratic polynomial permutations (QPP) interleavers are presented. The selection criterion proposed here was the convergence of the decoding process of duo-binary turbo codes. The analyses for ten best duo-binary memory 3 convolutional component codes and for Asynchronous Transfer Mode (ATM) blocks, with length N=2×212 bits=53 bytes are performed. The best turbo-code and permutation combination we found achieves a frame error rate of 10-4 at less than 0.75 decibels from the Shannon limit.