A blind adaptive decision feedback equalizer
Zhe Zhang · Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University · 2004
The equalization of channels is a key technique in modern communication system. How to improve the performance of equalizers is a hot topic. This study utilized an unsupervised (blind) adaptive decision feedback equalizer (DFE). It can be thought of as the cascade of four devices, whose main components are a recursive filter(R) and a transversal filter (T). In the starting mode, R comes first and whitens its own output by means of a prediction principle, while T removes the remaining inter-symbol interference using the Godard (or Shalvi-Weinstein) algorithm. In the tracking mode the equalizer became the classical DFE controlled by the decision-directed least-mean-square algorithm. With the same computational complexity, the unsupervised equalizer exhibited the same convergence speed, steady-state MSE , and bit-error-rate as the trained conventional DFE ,but it requires no training. So the unsupervised adaptive decision feedback equalizer suggested in this study has better adaptability for channel equalization.