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Research On Parameters' Effect On The Performance Of Adaptive Feedback Decision Equalizer

Posted on:2009-01-29Degree:MasterType:Thesis
Country:ChinaCandidate:J LiFull Text:PDF
GTID:2178360272985998Subject:Circuits and Systems
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Equalizer is usually used for removing the intersymbol interference (ISI) in digital communication. Decision feedback equalizer (DFE) based on transversal equalizer is usually adopted in many scenarios for its good ability in MMSE performance, combating ISI, and low computational complexity. In this paper, Wiener optimal filtering is introduced, and the linear equalizer optimal filtering theory is extended to the DFE which has a feedback. The structure of DFE, the relationship of the feedforward filter tap-length, feedback filter tap-length and the decision delay, and their effect to the MMSE performance of DFE is summarized. The DFE could get its optimal MMSE performance via adjusting the three components.In this paper, the VT-DLA which is used in transversal equalizer is mended, and the new algorithm is used in the feedforward filter. On the base of modified algorithm, the relation between feedback filter tap-length and the MMSE performance is investigated. It is shown that the feedback tap-length is not the longer the better, when the feedforward tap-length converges to a certain range, and the decision delay maintains in a fixed value. There is an optimum value making adaptive DFE getting a better MMSE performance. A structure of Error feedback DFE is enumerated, the principium of the Error feedback DFE is introduced, and another structure of Error feedback DFE is proposed according its structured characteristic.
Keywords/Search Tags:Adaptive, Decision Feedback Equalizer, MMSE, Equalizer Tap-Length
PDF Full Text Request
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