New Neural Network Based Nonlinear and Multipath Distortion Equalizer for FTTA Systems

Jun IDO  Minoru OKADA  Shozo KOMAKI  

Publication
IEICE TRANSACTIONS on Communications   Vol.E80-B   No.8   pp.1138-1144
Publication Date: 1997/08/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Mobile Computing)
Category: 
Keyword: 
digital communication,  nonlinear distortion,  multipath,  equalizer,  neural network,  QAM,  

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Summary: 
A new Neural Network Equalizer (NNE), employing multilayer feedforward neural network, is proposed as a compensation method for nonlinear and multipath distortion that arises from FTTA (Fiber To The Air) system. If a signal in a channel is affected by nonlinear distortion, the conventional Decision Feedback Equalizer (DFE) finds difficulty in perfect compensation of it. To compensate for nonlinear distortion as well as multipath distortion, an equalizer, employing neural network, is investigated. A new neural network equalizer, yielding a cubic function as unit output function, is proposed in order to compensate the nonlinear distortion effectively. We also propose an initial weights of neural network for preventing from local minimum. Computer simulation results show that the compensation performance of the new NNE is superior to the conventional DFE and the conventional NNE.