A simple stopping criterion for turbo decoding

This letter proposes a simple stopping criterion for turbo decoding that extends the existing sign change ratio (SCR) technique. The new sign difference ratio (SDR) criterion counts the sign differences between the a priori information and the extrinsic information. Unlike the SCR, it requires no extra data storage, Simulations comparing the new technique with other well known stopping criteria show that the proposed SDR scheme achieves similar performance in terms of BER, FER, and the average number of iterations, while requiring lower complexity. A GENIE scheme is included as the limit of all possible stopping criteria.