A model for turbo decoder

Recently, turbo code has gathered much attention for its outstanding performance. Many literatures have been published on algorithm and applications of turbo code. However, there is little progress on the decoding mechanism of turbo decoder. In this paper we propose an asymmetry AWGN (additive white Gaussian noise channel) model. The proposed model simplified the turbo decoder to an RSC decoder. Through the simulation of the proposed model, two mechanisms of the TURBO decoder have been uncovered. First, turbo decoder improves the S/N (signal to noise) rate of systematic code. Second, turbo decoder improves affection of the systematic code. The simulation result shows that the proposed model is consistent with turbo decoder