On the Convergence of a Turbo Equalizer in terms of AMI

Abstract—The average mutual information (AMI) is a useful metric to study the convergence behavior of the iteratively decodable receivers. A turbo equalizer (TEQ) has been considered as a class of such iterative receiver. We derive a new expression for the AMI at the equalizer input under no apriori information condition. Its value is compared with that at the output of the equalizer under perfect apriori information conditions. The importance of this study is to evaluate the effect of a TEQ on a signal corrupt with severe intersymbol interference and additive white Gaussian noise (AWGN). This study is useful for studying the convergence behavior of a TEQ without resorting to time consuming extensive computer simulations as usually reported in literature. Index Terms—SCS, AMI, TEQ, apriori information, ISI I

Analysis of Linear Turbo Equalizer via EXIT Chart

In this paper, we propose a method for analysis of linear turbo equalization based on extrinsic information transfer (EXIT) charts. Given channel knowledge and therefore the optimum linear equalizer coefficients, evolution of soft information of the soft-input soft-output (SISO) equalizer can be estimated via computing bit error rates (BER) analytically. Compared to conventional analysis methods, the proposed method predicts the linear turbo equalizer performance without running extensive simulations to obtain the SISO equalizer EXIT charts. Using an empirically generated SISO decoder EXIT chart, convergence analysis can be undertaken. Further, the method provides a bound on the achievable BER for given channels and an estimate of equalizer complexity. These approximate analyses are validated via computer simulations

Analysis of Linear Turbo Equalizer via EXIT Chart

Abstract — In this paper, we propose a method for analysis of linear turbo equalization based on extrinsic information transfer (EXIT) charts. Given channel knowledge and therefore the optimum linear equalizer coefficients, evolution of soft information of the soft-input soft-output (SISO) equalizer can be estimated via computing bit error rates (BER) analytically. Compared to conventional analysis methods, the proposed method predicts the linear turbo equalizer performance without running extensive simulations to obtain the SISO equalizer EXIT charts. Using an empirically generated SISO decoder EXIT chart, convergence analysis can be undertaken. Further, the method provides a bound on the achievable BER for given channels and an estimate of equalizer complexity. These approximate analyses are validated via computer simulations. I