Analysis and compensation of nonlinear power amplifier effects in multi-antenna OFDM systems

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Gregorio, Fernando Hugo
dc.date.accessioned 2012-02-24T08:45:13Z
dc.date.available 2012-02-24T08:45:13Z
dc.date.issued 2007-11-19
dc.identifier.isbn 978-951-22-9001-7
dc.identifier.issn 1458-6401
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2943
dc.description.abstract The high peak to average power ratio (PAPR) levels associated with multicarrier systems require the use of linear power amplifiers (PA) with large dynamic range. Unfortunately, linearity and power efficiency are two conflicting specifications for practical PAs. However, systems with high power efficiency are required, for example, in case of battery operated mobile terminals. Thus, the PA needs to operate in a high power efficiency region which compromises the linearity constraints. The evaluation of the effect of nonlinear amplification on the system performance is an important issue that must be considered in a realistic system design. This thesis first addresses the performance analysis of multiuser OFDM systems (space division multiple access (SDMA)-OFDM) employing nonlinear PAs. Bit error probability (BEP) and capacity expressions are derived for an OFDM system with diversity, assuming a memoryless PA. Moreover, BEP expressions are derived for an orthogonal space-time coded (OSTBC)-OFDM system that include the effect of a broadband nonlinear PA and imperfect memory compensation. Thereafter, techniques to reduce the effects of power amplifier distortion are proposed. We consider techniques that can be implemented either in the receiver, the transmitter, or as a combination of both, all with the same goal of relieving the linearity constaints and improving the power efficiency. A low PAPR OFDM implementation is addressed where subcarriers are allocated to different users in such a way that the generated intermodulation distortion is kept at minimum. Then, we propose the combination of multiuser detection and nonlinear distortion mitigation techniques. Initially, knowledge of the PA model (modelled as memoryless) is required for the implementation. The extension to broadband PAs and to PA model estimation in the receiver are also made. Efficient channel estimation strategies are developed that work in the presence of nonlinear distortion. Finally, a split predistorter structure to remove nonlinear distortion caused by a broadband PA is proposed. The idea is to reduce the transmitter complexity by distributing the predistorter tasks such that the transmitter compensates for the static nonlinearity, and the receiver equalizes the PA memory. en
dc.description.abstract Lähetystehon suuri vaihtelu monikantoaaltojärjestelmissä asettaa tiukkoja vaatimuksia tehovahvistimille. Vahvistimien lineaarisen alueen pitää olla suuri, mikä johtaa huonoon hyötysuhteeseen ja suureen tehonkulutukseen vahvistimen operoidessa lineaarisella alueella. Jos vahvistimen hyötysuhde halutaan pitää korkeana, kuten esimerkiksi akuilla toimivissa kannettavissa päätelaitteissa, vahvistettu signaali väistämättä vääristyy. Näiden epälineaaristen vääristymien kompensointi on tärkeä osa langattomien tietoliikennejärjestelmien suunnittelua. Tässä työssä tarkastellaan epälineaaristen tehovahvistimien vaikutusta monen käyttäjän OFDM-järjestelmiin ja näiden vaikutusten kompensointia lähettimessä ja/tai vastaanottimessa, kun päätelaitteissa voi olla useampia antenneja. Lähettimessä vääristymien epäedullista vaikutusta vähennetään lomittelemalla lähetettyjä kantoaaltoja eri lähetysantennien kesken. Vastaanottimessa monen käyttäjän ilmaisu yhdistetään vääristymien kompensointiin ja kanavaestimointiin. Lopuksi työssä kehitetään algoritmi, jossa vääristymien kompensointi jaetaan lähettimen ja vastaanottimen kesken. Työssä myös johdetaan vastaanottimen virhetodennäköisyyslausekkeet ja kanavan kapasiteettilausekkeet erilaisille systeemimalleille, kun lähetetty signaali on vääristynyt epälineaarisesti. fi
dc.format.extent 117, [46]
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Report / Helsinki University of Technology, Signal Processing Laboratory en
dc.relation.ispartofseries 61 en
dc.relation.haspart F. Gregorio, T.I. Laakso and R. Wichman. Comparison of clustered and antenna interleaving OFDM in multiple-antenna systems with amplifier nonlinearities, in Proceedings of the 2004 IEEE International Conference on Signal Processing and Communications, SPCOM 2004, pp. 111-115, December 2004, Bangalore, India. [article1.pdf] © 2004 IEEE. By permission.
dc.relation.haspart F. Gregorio and T.I. Laakso. A novel carrier allocation method for multiuser OFDM system with amplifier nonlinearities, in Proceedings of the 13th European Signal Processing Conference, EUSIPCO 2005, September 2005, Antalya, Turkey. [article2.pdf] © 2005 by authors.
dc.relation.haspart F. Gregorio, T.I. Laakso and J. Cousseau. Receiver cancellation of nonlinear power amplifier distortion in SDMA-OFDM systems, in Proceedings of the 2006 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2006, pp. IV 325-328, May 2006, Toulouse, France. [article3.pdf] © 2006 IEEE. By permission.
dc.relation.haspart F. Gregorio, S. Werner, J. Cousseau and T.I. Laakso. Iterative channel estimation for multiuser OFDM systems in the presence of power amplifier nonlinearities, in Proceedings of the 17th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC 2006, September 2006, Helsinki, Finland. [article4.pdf] © 2006 IEEE. By permission.
dc.relation.haspart F. Gregorio, S. Werner, T.I. Laakso and J. Cousseau. Receiver cancellation technique for nonlinear power amplifier distortion in SDMA-OFDM systems, IEEE Transactions on Vehicular Technology, vol. 56, no. 5, pp. 2499-2516, September 2007. [article5.pdf] © 2007 IEEE. By permission.
dc.relation.haspart F. Gregorio, S. Werner, R. Wichman and J. Cousseau. Split predistortion approach for reduced complexity terminal in OFDM systems, in Proceedings of the 65th IEEE Vehicular Technology Conference, VTC 2007, pp. 2697-2701, April 2007, Dublin, Ireland. [article6.pdf] © 2007 IEEE. By permission.
dc.relation.haspart F. Gregorio, S. Werner, J. Hämäläinen, R. Wichman and J. Cousseau. BEP analysis of OSTBC-OFDM systems with broadband PA and imperfect memory compensation, IEEE Communications Letters, 2007, to appear. [article7.pdf] © 2007 IEEE. By permission.
dc.relation.haspart F. Gregorio, S. Werner, J. Cousseau and R. Wichman. Broadband power amplifier distortion cancellation with model estimation in the receiver, in Proceedings of the 8th IEEE Workshop on Signal Processing Advances in Wireless Communications, SPAWC 2007, June 2007, Helsinki, Finland. [article8.pdf] © 2007 IEEE. By permission.
dc.subject.other Electrical engineering en
dc.title Analysis and compensation of nonlinear power amplifier effects in multi-antenna OFDM systems en
dc.title Epälineaaristen tehovahvistimien suorituskykyanalyysi ja epälineaarisuuksien kompensointi usean antennin OFDM-järjestelmissä fi
dc.type G5 Artikkeliväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Electrical and Communications Engineering en
dc.contributor.department Sähkö- ja tietoliikennetekniikan osasto fi
dc.subject.keyword nonlinear power amplifiers en
dc.subject.keyword OFDM en
dc.subject.keyword PAPR en
dc.subject.keyword nonlinear distortion en
dc.subject.keyword tietoliikennetekniikka fi
dc.subject.keyword tehovahvistin fi
dc.subject.keyword OFDM fi
dc.subject.keyword moniantennitekniikka fi
dc.identifier.urn urn:nbn:fi:tkk-010714
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.contributor.lab Signal Processing Laboratory en
dc.contributor.lab Signaalinkäsittelytekniikan laboratorio fi


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