An Exponential Model for Evaluating Error Performance of Turbo Codes

In this paper, an exponential model is proposed to approximate the error performance of Turbo codes within low and intermediate SNR region. Our analysis unveils that, the proposed exponential model offers a simple but effective method to approximate the waterfall region performance of Turbo codes, which is generally intricate for analytical bounding techniques. By combining the proposed exponential model with the well known union bound estimate, the paper derives a combined performance model to extend the performance estimate within moderate to high SNR region. Moreover, it is shown that, only the free distance term of the weight spectrum is not always enough for a reasonable estimate of the error floor region performance, especially when the free distance multiplicity is small. Numerical results are presented to validate the applicability of the proposed performance model.