Decision feedback equalization
Rito, Brian Ysmael Dimaunahan
Date of Issue2017-08-28
School of Electrical and Electronic Engineering
Decision Feedback Equalization (DFE) is a form of non-linear symbol-by-symbol equalization in which past decisions are used to cancel post-cursor inter-symbol interference (ISI). The main cause of ISI is when the transmitted symbol duration is comparable to the channels’ delay spread. DFE is appealing since it is easy to implement and does not enhance noise, as much as linear equalizers do. However, wrong decisions tend to give rise to more errors; this phenomenon is called error propagation. This report studies the basic principle and operations of DFE. It also briefly discusses error propagation and a few popular mitigation techniques such as constrained feedback method and erasure slicer method. Simulation results using MATLAB are included to aid and support discussions. It is seen that DFE performs better than the traditional linear equalizers, and error propagation can be effectively mitigated using the mentioned techniques.
DRNTU::Engineering::Electrical and electronic engineering