Performance evaluation of linear turbo receivers using analytical exit functions

Turbo receivers have gained significant importance in recent years, combating efficiently the effect of interference-limited propagation channels through the iterative exchange of information between the front-end receiver and the channel decoder. Such iterative process is difficult to describe in a closed form so the performance evaluation is usually done by means of extensive numerical simulations. We propose an analytical method allowing for performance evaluation of turbo receivers which may be used for system-level analysis or link adaptation. The proposed approach, based on the so-called EXIT analysis, allows for an accurate prediction of the receiver´s coded bit- or block-error rates for each iteration as a function of the channel state. We illustrate the paper applying the proposed method to MIMO systems.