Decision feedback equalization

Abstract

Decision Feedback Equalization (DFE) is a form of non-linear symbol-by-symbol equalization in
\nwhich past decisions are used to cancel post-cursor inter-symbol interference (ISI). The main
\ncause of ISI is when the transmitted symbol duration is comparable to the channels’ delay spread.
\nDFE is appealing since it is easy to implement and does not enhance noise, as much as linear
\nequalizers do. However, wrong decisions tend to give rise to more errors; this phenomenon is
\ncalled error propagation.
\nThis report studies the basic principle and operations of DFE. It also briefly discusses error
\npropagation and a few popular mitigation techniques such as constrained feedback method and
\nerasure slicer method. Simulation results using MATLAB are included to aid and support
\ndiscussions. It is seen that DFE performs better than the traditional linear equalizers, and error
\npropagation can be effectively mitigated using the mentioned techniques.

Keywords

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