A new technique for computing the weight spectrum of turbo-codes

We obtain an accurate and simple analytical approximation to the bit error probability of maximum-likelihood decoding of parallel concatenated convolutional codes (turbo-codes) by extending a result from the paper by Fossorier et al. (see IEEE Trans. Inform. Theory, vol.45, no.5, p.1646-8, 1999), which investigates the weight enumerating function of terminated convolutional codes, to compute their conditional weight enumerating function.