On the outage probability of MMSE turbo equalization in frequency-selective Rayleigh fading channels

We analyze the outage probability of frequency domain minimum mean squared error turbo equalization over frequency-selective Rayleigh fading channels with exponential delay power profile. A correlation chart analysis is used to evaluate the convergence property of the iterative system. Based on the convergence characteristic of the equalizer and decoder, we derive a closed form approximation to the outage probability of the turbo equalizer. Specifically, an upper bounding technique and a central limit theorem are used to show that the outage probability is well approximated by a sum of complementary Gaussian error functions. Numerical results of outage probability simulations of the turbo equalizer in channels with different delay power profiles are presented to demonstrate the accuracy of the proposed method.