Improved algorithms for high rate turbo code weight distribution calculation

We discuss algorithms for determining exactly the lower terms of the weight distribution of a turbo code. Several improvements of the recently introduced algorithm by R. Garello et al. (see IEEE J. Select. Areas Commun., vol.19, p.800-12, 2001) are outlined. The techniques presented improve the observed asymptotic complexity by a factor proportional to the information length. We further apply the improved algorithm to high rate turbo codes using high rate non-punctured constituent codes. To reduce complexity, the constituent codes are represented by a minimal information bit oriented trellis.