Markovian model of the error probability density and application to the error propagation probability computation of the weighted, decision feedback equalizer

2002 ◽  
Author(s):  
A. Goupil ◽  
J. Palicot
Keyword(s):  
Probability Density ◽  
Error Propagation ◽  
Error Probability ◽  
Decision Feedback ◽  
Decision Feedback Equalizer ◽  
Markovian Model

scholarly journals A Low-Complexity Decision Feedforward Equalizer Architecture for High-Speed Receivers on Highly Dispersive Channels

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Ariel L. Pola ◽  
Juan E. Cousseau ◽  
Oscar E. Agazzi ◽  
Mario R. Hueda
Keyword(s):  
Error Probability ◽  
High Speed ◽  
Low Complexity ◽  
Decision Feedback ◽  
Decision Feedback Equalizer ◽  
Channel Memory ◽  
Exponential Increase ◽  
Dispersive Channels ◽  
Large Memory ◽  
Feedforward Equalizer

This paper presents an improved decision feedforward equalizer (DFFE) for high speed receivers in the presence of highly dispersive channels. This decision-aided equalizer technique has been recently proposed for multigigabit communication receivers, where the use of parallel processing is mandatory. Well-known parallel architectures for the typical decision feedback equalizer (DFE) have a complexity that grows exponentially with the channel memory. Instead, the new DFFE avoids that exponential increase in complexity by using tentative decisions to cancel iteratively the intersymbol interference (ISI). Here, we demostrate that the DFFE not only allows to obtain a similar performance to the typical DFE but it also reduces the compelxity in channels with large memory. Additionally, we propose a theoretical approximation for the error probability in each iteration. In fact, when the number of iteration increases, the error probability in the DFFE tends to approach the DFE. These benefits make the DFFE an excellent choice for the next generation of high-speed receivers.

scholarly journals Decision Feedback Blind Equalizer with Tap-Leaky Whitening for Stable Structure-Criterion Switching

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Vladimir R. Krstić ◽  
Miroslav L. Dukić
Keyword(s):  
Error Propagation ◽  
Parametric Optimization ◽  
Stable Structure ◽  
Decision Feedback ◽  
Gradient Algorithm ◽  
Decision Feedback Equalizer ◽  
Switching Performance ◽  
Cost Criterion ◽  
Propagation Effects ◽  
The Cost

The research presented in this paper improves the structure-criterion switching performance of the blind decision feedback equalizer (DFE) which eliminates error propagation effects by optimizing both the structure and the cost criterion. To conquer the complexity of the 64-QAM (quadrature amplitude modulated) signal constellation, the stochastic entropy-gradient algorithm is additionally regularized by the coefficient leaky term to avoid a coefficients norm overgrowth of the received signal whitener. Effectively, the leak of coefficients is employed to ensure a stable structure-criterion switching of DFE between blind and decision-directed operation modes. The optimization of the resulting whitening algorithm is achieved by means of two free, leaky and entropic, parameters which act in opposition to each other. Both, the influence of the 64-QAM signal on the feedback filter behavior and the parametric optimization of the whitening algorithm are analyzed through simulations.

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