Nix, AR

Noune, MB

English

There is considerable interest in the use of single carrier frequency division multiple access (SC-FDMA) as the uplink transmission scheme in the 3GPP Long Term Evolution standard. This interest is justified by the inherent single carrier structure of SC-FDMA, which results in reduced sensitivity to phase noise and a lower peak-to-average power ratio (PAPR) compared to orthogonal frequency division multiple access. This, consequently, makes it more attractive for low cost devices with limited transmit power. In this paper we demonstrate how precoding the uplink transmission is an alternative signal processing technique to equalization in order to combat the frequency selective nature of the propagation channel. The frequency-domain implementation of Tomlinson-Harashima precoding (THP) for uplink SC-FDMA is proposed. We investigate the BER performance and the PAPR characteristics of the preceded SC-FDMA waveform for ZF and MMSE based THP. Results reported here show that the MMSE-THP outperforms the ZF-THP in terms of BER performance and PAPR.There is considerable interest in the use of single carrier frequency division multiple access (SC-FDMA) as the uplink transmission scheme in the 3GPP Long Term Evolution standard. This interest is justified by the inherent single carrier structure of SC-FDMA, which results in reduced sensitivity to phase noise and a lower peak-to-average power ratio (PAPR) compared to orthogonal frequency division multiple access. This, consequently, makes it more attractive for low cost devices with limited transmit power. In this paper we demonstrate how precoding the uplink transmission is an alternative signal processing technique to equalization in order to combat the frequency selective nature of the propagation channel. The frequency-domain implementation of Tomlinson-Harashima precoding (THP) for uplink SC-FDMA is proposed. We investigate the BER performance and the PAPR characteristics of the preceded SC-FDMA waveform for ZF and MMSE based THP. Results reported here show that the MMSE-THP outperforms the ZF-THP in terms of BER performance and PAP

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                          Noune, M. B., & Nix, A. R. (2009). A novel frequency-domainimplementation of Tomlinson-Harashima precoding for SC-FDMA. In IEEE69th Vehicular Technology Conference, 2009 (VTC Spring 2009),Barcelona, Spain. (pp. 1 - 5). Institute of Electrical and Electronics Engineers(IEEE). 10.1109/VETECS.2009.5073320Link to published version (if available):10.1109/VETECS.2009.5073320Link to publication record in Explore Bristol ResearchPDF-documentUniversity of Bristol - Explore Bristol ResearchGeneral rightsThis document is made available in accordance with publisher policies. Please cite only the publishedversion using the reference above. Full terms of use are available:http://www.bristol.ac.uk/pure/about/ebr-terms.htmlTake down policyExplore Bristol Research is a digital archive and the intention is that deposited content should not beremoved. However, if you believe that this version of the work breaches copyright law please contactopen-access@bristol.ac.uk and include the following information in your message:• Your contact details• Bibliographic details for the item, including a URL• An outline of the nature of the complaintOn receipt of your message the Open Access Team will immediately investigate your claim, make aninitial judgement of the validity of the claim and, where appropriate, withdraw the item in questionfrom public view.Centre for Communications ResearchWhy SC-FDMA ?• OFDMA is not well-suited to the uplink transmission in the 3GPP LTE as a result of its high PAPR.• SC-FDMA , also known as the DFT precoded OFDMA, has been proposed in the LTE standard for the uplink instead. • SC-FDMA is also regarded as a form of SC-FDE with a flexibility in resource allocation.Single Carrier Frequency Division Multiple Access (SC-FDMA) is the uplink transmission scheme in the 3GPP LTE standard. SC-FDMA can be used with a range of single carrier equalization techniques to combat ISI. In fact a common assumption in SC-FDMA is to use Linear and Decision Feedback Frequency-Domain Equalization (FDE). We propose the frequency-domain implementation of Tomlinson-Harashima Precoding (THP) for uplink SC-FDMA, as an alternative signal processing technique to equalization, in order to achieve an ISI-free signal at the receiver by performing ISI cancellation prior to transmission.• Precoding requires perfect knowledge of the uplink channel at the transmitter.(i) SC-FDMA transmitter and receiver Structures (ii) PAPR Characteristics of SC-FDMAA Novel Frequency-Domain Implementation of Tomlinson-Harashima Precoding for SC-FDMA Mohamed NOUNE and Prof. Andrew NIXemail: Mohamed.Noune@bris.ac.uk, Andy.Nix@bris.ac.uk0 2 4 6 8 10 12 14 16 1810-410-310-210-1100PAPR (dB)Pr(PAPR>)CCDF of the Peak-to-Average Power Ratio for different OFDM(A) Systems  OFDMOFDMA16-QAM SC-FDMAQPSK SC-FDMAQPSK SC-FDMA (=0.2)QPSK SC-FDMA (=0.5)QPSK SC-FDMA (=0.7)QPSK SC-FDMA (=1)Performance of SC-FDMA with FDE :• FDE is a very attractive signal processing technique to deal with large time dispersive multipath channels, and can be implemented in the form of an FD-LE or an FD-DFE.• Although FD-DFE offers a performance that is superior to FD-LE, it suffers from a performance degradation as a result of error propagation, especially for long delay spread channels and coded systems.0 5 10 15 20 25 3010-410-310-210-1100SNR (dB)BERUncoded BER of SC-FDMA with DFE under SCME  LFDMA-LELFDMA-DFEDFDMA-LEDFDMA-DFE0 5 10 15 20 25 30 35 40 4510-310-210-1100SNR (dB)BLERBLER of SC-FDMA with DFE under SCME  QPSK,Rc=1/2QPSK-LEQPSK-DFE16QAM,Rc=1/216QAM-LE16QAM-DFE1/2-rate16QAM(with LE)UncodedQPSK(with DFE)(i) Uncoded BER of SC-FDMA with FDE (ii) BLER of SC-FDMA with FDEPerformance of SC-FDMA with FDE under SCMEConclusions :• THP achieves the ideal-DFE performance for coded and uncoded systems.• Because the PAPR of the precoder's output is dependent on the channel  fading, it is essential to employ some form of PAPR reduction.SC-FDMA Transceiver and PAPRTomlinson-Harashima Precoding :• THP tackles the error propagation problem in a DFE and offers a further improvement when coding is applied.• THP combats ISI transmissions, and achieves transmission at the full channel capacity.TD Tomlinson-Harashima Precoding for SC-FDMA :• The time-domain operation of THP is connected to the signal constellation, SC-FDMA, however, does not have a distinct constellation.• The precoder’s input is the SC-FDMA signal after CP insertion transforms the linear convolution into cyclical convolution.  • By rearranging the previous equation and taking the N-point DFT:Structure of conventional Tomlinson-Harashima Precoding• The output of the THP is:L is the channel delay spread.• The Tdomain implementation of THP is a realizable and effective implementation, especially as the channel delay spread increases.• The THP coefficients can be designed according to the ZF or MMSE criterion.(i) PAPR of ZF and MMSE THP. (ii) BER of ZF and MMSE THPPerformance of SC-FDMA with THP under SCME

A novel frequency-domain implementation of Tomlinson-Harashima precoding for SC-FDMA

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A Novel Frequency-Domain Implementation of Tomlinson-Harashima Precoding for SC-FDMA

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A novel frequency-domain implementation of Tomlinson-Harashima precoding for SC-FDMA

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