On performance prediction of an iterative multi-antenna receiver

We use the statistical properties of a frequency-selective single-input multiple-output channel to predict the distribution of the signal-to-interference-and-noise ratio (SINR) at the output of an iterative equalizer. The SINR distribution is then used to derive the distribution of the variance of the soft demapped bit log likelihood ratios (LLRs). Extrinsic information transfer (EXIT) charts establish a relationship between the LLR variance and mutual information. Thus, by comparing the semi-analytically calculated LLR variance distribution at the demapper output to a previously measured EXIT chart of a turbo decoder, we can reliably estimate the expected frame error ratio. This prediction method is extended for the Chase combining hybrid automatic repeat-request protocol.