Non-Binary Turbo Codes Interleavers

In this paper the particularities of the interleavers used in the case of the Recursive Systematic Convolutional Code (RSC), n/(n+2) rate, with n=2, unpunctured non-binary turbo codes (NBTC) were described. The interleavers: block, pseudo-random and new interleaving methods are presented. These new interleaving methods were elaborated starting from the particular form of the date accepted by non-binary turbo codes and they constitute an extension of the classic methods. The AWGN (Additive White Gaussian Noise) and the BPSK (Binary Phase Shift Keying) modulation were employed. The turbo decoder was used 15 iterations for each block. A Log Likelihood Ratio (LLR) stop criterion was selected. The BER (Bit Error Rate) and FER (Frame Error Rate) performances for small interleaver lengths (N=448) and for high interleaver lengths (more than 1000 bits) were obtained. In the case of FER performances, for each interleaving length, the Shannon’s limits were computed, too.