An Analytical Approach for Finite Block Length Performance Analysis of Turbo Frequency-Domain Equalization

Abstract

Turbo frequency-domain equalization has been shown to be an efficient technique in overcoming intersymbol interference (ISI). To analyze this system, the extrinsic information transfer (EXIT) chart can be employed to avoid extensive simulations. The histogram-based approach in the EXIT chart makes this method considerably complex in analyzing the performance of turbo equalizers over nonstatic channels. Likewise, the EXIT chart accurately predicts the performance only for systems with extremely large block lengths due to the asymptotic analysis that is utilized in this tool. In this paper, we propose a new method to solve these issues. The analytical approach in our method in deriving the equalizer curve eliminates the need for histogram generation. This makes the implementation of this method remarkably simpler than that of the EXIT chart. Utilizing the empirically generated decoder bit-error-rate curve in this method enables us to accurately predict the performance of systems with reasonably small block lengths. Through comparative simulations, we demonstrate the efficiency of this method in predicting the bit-error-rate performance of a turbo frequency-domain equalizer for different constellations and different equalizer schemes.