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LMMSE turbo equalization based on factor graphs

Journal Article


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Abstract


  • In this paper, a vector-form factor graph representation is derived for intersymbol interference (ISI) channels. The resultant graphs have a tree-structure that avoids the short cycle problem in existing graph approaches. Based on a joint Gaussian approximation, we establish a connection between the LLR (log-likelihood ratio) estimator for a linear system driven by binary inputs and the LMMSE (linear minimum mean-square error) estimator for a linear system driven by Gaussian inputs. This connection facilitates the application of the recently proposed Gaussian message passing technique to the cycle-free graphs for ISI channels. We also show the equivalence between the proposed approach and the Wang-Poor approach based on the LMMSE principle. An attractive advantage of the proposed approach is its intrinsic parallel structure. Simulation results are provided to demonstrate this property. © 2008 IEEE.

UOW Authors


Publication Date


  • 2008

Citation


  • Q. Guo & L. Ping, "LMMSE turbo equalization based on factor graphs," IEEE Journal on Selected Areas in Communications, vol. 26, (2) pp. 311-319, 2008.

Scopus Eid


  • 2-s2.0-38849090643

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1995&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/986

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 311

End Page


  • 319

Volume


  • 26

Issue


  • 2

Place Of Publication


  • United States

Abstract


  • In this paper, a vector-form factor graph representation is derived for intersymbol interference (ISI) channels. The resultant graphs have a tree-structure that avoids the short cycle problem in existing graph approaches. Based on a joint Gaussian approximation, we establish a connection between the LLR (log-likelihood ratio) estimator for a linear system driven by binary inputs and the LMMSE (linear minimum mean-square error) estimator for a linear system driven by Gaussian inputs. This connection facilitates the application of the recently proposed Gaussian message passing technique to the cycle-free graphs for ISI channels. We also show the equivalence between the proposed approach and the Wang-Poor approach based on the LMMSE principle. An attractive advantage of the proposed approach is its intrinsic parallel structure. Simulation results are provided to demonstrate this property. © 2008 IEEE.

UOW Authors


Publication Date


  • 2008

Citation


  • Q. Guo & L. Ping, "LMMSE turbo equalization based on factor graphs," IEEE Journal on Selected Areas in Communications, vol. 26, (2) pp. 311-319, 2008.

Scopus Eid


  • 2-s2.0-38849090643

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=1995&context=eispapers

Ro Metadata Url


  • http://ro.uow.edu.au/eispapers/986

Has Global Citation Frequency


Number Of Pages


  • 8

Start Page


  • 311

End Page


  • 319

Volume


  • 26

Issue


  • 2

Place Of Publication


  • United States