Complex LMS fuzzy adaptive equalizer with decision feedback
S.Y. Lee, J.B. Kim, K.Y. Lee, C.W. Lee · 2002
A complex fuzzy adaptive decision feedback equalizer (CFADFE) based on the LMS algorithm is proposed. The CFADFE is constructed from a set of changeable complex fuzzy if-then rules and the 'if' part of the rule are characterized by the state of the decision feedback. The computational complexity is reduced dramatically by using the decision feedback. The CFADFE not only reduces the computational complexity but also improves the performance compared with the conventional complex fuzzy adaptive equalizers. The adaptation speed is greatly improved by incorporating some linguistic information about the channel into the equalizer. It is applied to a QAM digital communication system with linear and nonlinear complex channel characteristics.