Three different effective solutions and parallel implement method of computing the posteriori probability of received signal were proposed to overcome the high calculation complexity of iterative equalization based on factor graph for nonlinear channel distortion. Equalizer and decoder work interactively in factor graph equalization and the performance of the system was improved while the calculation complexity grew exponentially with channel memory length. Multidimensional integration was adopted by Markov chain Monte Carlo algorithm and parallel Gibbs sampling was implemented by factor graph partition. The calculation complexity was reduced. Simulation demonstrated that it overcomes the non-linear distortion of high order modulation over satellite channel and it is suitable to hardware or multi-core implement.
