Expectation Propagation as Turbo Equalizer in ISI Channels

In probabilistic equalization of channels with inter-symbol interference, the BCJR algorithm and its approximations become intractable for high-order modulations, even for moderate channel dispersions. In this paper, we introduce a novel soft equalizer to approximate the symbol a posteriori probabil...

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Autores: Santos, Irene, Murillo Fuentes, Juan José, Boloix Tortosa, Rafael, Arias de Reyna Domínguez, Eva María, Olmos, Pablo M.
Formato: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2017
País:España
Recursos:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/162678
Acesso em linha:https://hdl.handle.net/11441/162678
https://doi.org/10.1109/TCOMM.2016.2616141
Access Level:acceso abierto
Palavra-chave:Expectation propagation (EP)
BCJR
Complex-valued
Turbo equalization
ISI
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repository_id_str
spelling Expectation Propagation as Turbo Equalizer in ISI ChannelsSantos, IreneMurillo Fuentes, Juan JoséBoloix Tortosa, RafaelArias de Reyna Domínguez, Eva MaríaOlmos, Pablo M.Expectation propagation (EP)BCJRComplex-valuedTurbo equalizationISIIn probabilistic equalization of channels with inter-symbol interference, the BCJR algorithm and its approximations become intractable for high-order modulations, even for moderate channel dispersions. In this paper, we introduce a novel soft equalizer to approximate the symbol a posteriori probabilities (APP), where the expectation propagation (EP) algorithm is used to provide an accurate estimation. This new soft equalizer is presented as a block solution, denoted as block-EP (BEP), where the structure of the matrices involved is exploited to reduce the complexity order to O(L N2), i.e., linear in the length of the channel, L, and quadratic in the frame length, N. The solution is presented in complex-valued formulation within a turbo equalization scheme. This algorithm can be cast as a linear minimum-mean-squared-error (LMMSE) turbo equalization with double feedback architecture, where constellations being discrete is a restriction exploited by the EP that provides a first refinement of the APP. In the experiments included, the BEP exhibits a robust performance, regardless of the channel response, with gains in the range 1.5-5 dB compared with the LMMSE equalization. © 2016 IEEE.Institute of Electrical and Electronics Engineers (IEEE)Teoría de la Señal y ComunicacionesTIC155: Tratamiento de Señales y Comunicaciones2017info:eu-repo/semantics/articleinfo:eu-repo/semantics/acceptedVersionapplication/pdfapplication/pdfhttps://hdl.handle.net/11441/162678https://doi.org/10.1109/TCOMM.2016.2616141reponame:idUS. Depósito de Investigación de la Universidad de Sevillainstname:Universidad de Sevilla (US)Ingléshttps://ieeexplore.ieee.org/document/7587428/keywords#keywordsinfo:eu-repo/semantics/openAccessoai:idus.us.es:11441/1626782026-06-17T12:51:07Z
dc.title.none.fl_str_mv Expectation Propagation as Turbo Equalizer in ISI Channels
title Expectation Propagation as Turbo Equalizer in ISI Channels
spellingShingle Expectation Propagation as Turbo Equalizer in ISI Channels
Santos, Irene
Expectation propagation (EP)
BCJR
Complex-valued
Turbo equalization
ISI
title_short Expectation Propagation as Turbo Equalizer in ISI Channels
title_full Expectation Propagation as Turbo Equalizer in ISI Channels
title_fullStr Expectation Propagation as Turbo Equalizer in ISI Channels
title_full_unstemmed Expectation Propagation as Turbo Equalizer in ISI Channels
title_sort Expectation Propagation as Turbo Equalizer in ISI Channels
dc.creator.none.fl_str_mv Santos, Irene
Murillo Fuentes, Juan José
Boloix Tortosa, Rafael
Arias de Reyna Domínguez, Eva María
Olmos, Pablo M.
author Santos, Irene
author_facet Santos, Irene
Murillo Fuentes, Juan José
Boloix Tortosa, Rafael
Arias de Reyna Domínguez, Eva María
Olmos, Pablo M.
author_role author
author2 Murillo Fuentes, Juan José
Boloix Tortosa, Rafael
Arias de Reyna Domínguez, Eva María
Olmos, Pablo M.
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Teoría de la Señal y Comunicaciones
TIC155: Tratamiento de Señales y Comunicaciones
dc.subject.none.fl_str_mv Expectation propagation (EP)
BCJR
Complex-valued
Turbo equalization
ISI
topic Expectation propagation (EP)
BCJR
Complex-valued
Turbo equalization
ISI
description In probabilistic equalization of channels with inter-symbol interference, the BCJR algorithm and its approximations become intractable for high-order modulations, even for moderate channel dispersions. In this paper, we introduce a novel soft equalizer to approximate the symbol a posteriori probabilities (APP), where the expectation propagation (EP) algorithm is used to provide an accurate estimation. This new soft equalizer is presented as a block solution, denoted as block-EP (BEP), where the structure of the matrices involved is exploited to reduce the complexity order to O(L N2), i.e., linear in the length of the channel, L, and quadratic in the frame length, N. The solution is presented in complex-valued formulation within a turbo equalization scheme. This algorithm can be cast as a linear minimum-mean-squared-error (LMMSE) turbo equalization with double feedback architecture, where constellations being discrete is a restriction exploited by the EP that provides a first refinement of the APP. In the experiments included, the BEP exhibits a robust performance, regardless of the channel response, with gains in the range 1.5-5 dB compared with the LMMSE equalization. © 2016 IEEE.
publishDate 2017
dc.date.none.fl_str_mv 2017
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/11441/162678
https://doi.org/10.1109/TCOMM.2016.2616141
url https://hdl.handle.net/11441/162678
https://doi.org/10.1109/TCOMM.2016.2616141
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv https://ieeexplore.ieee.org/document/7587428/keywords#keywords
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Institute of Electrical and Electronics Engineers (IEEE)
publisher.none.fl_str_mv Institute of Electrical and Electronics Engineers (IEEE)
dc.source.none.fl_str_mv reponame:idUS. Depósito de Investigación de la Universidad de Sevilla
instname:Universidad de Sevilla (US)
instname_str Universidad de Sevilla (US)
reponame_str idUS. Depósito de Investigación de la Universidad de Sevilla
collection idUS. Depósito de Investigación de la Universidad de Sevilla
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.812455

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