Comparative Study of Turbo Equalization Schemes using Convolutional, Convolutional Turbo, and Block-Turbo Codes

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Description/Abstract

Turbo equalizers have been shown to be successful in mitigating the effects of inter-symbol interference introduced by partial response modems and by dispersive channels for code rates of $R \le 1/2$. In this contribution, we comparatively studied the performance of a range of binary phase-shift keying turbo equalizers employing block-turbo codes, namely Bose–Chaudhuri–Hocquenghen turbo codes, convolutional codes, and convolutional turbo codes having high code rates, such as $R = 3/4$ and $R = 5/6$, over a dispersive five-path Gaussian channel and an equally weighted symbol-spaced five-path Rayleigh fading channel. These turbo equalization schemes were combined with an iterative channel estimation scheme in order to characterize a realistic scenario. The simulation results demonstrated that the turbo-equalized system using convolutional turbo codes was the most robust system for all code rates investigated. Index Terms—Bose–Chaudhuri–Hocquenghen codes, convolutional codes, iterative decoding, iterative equalization, joint equalization and decoding, turbo codes, turbo decoding, turbo equalization.