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Journal Article•DOI•

Frequency domain equalization for single-carrier broadband wireless systems

David Falconer1, S.L. Ariyavisitakul, A. Benyamin-Seeyar2, B. Eidson3•
Carleton University1, Harris Corporation2, Conexant3
01 Apr 2002-IEEE Communications Magazine (IEEE)-Vol. 40, Iss: 4, pp 58-66
TL;DR: This article surveys frequency domain equalization (FDE) applied to single-carrier (SC) modulation solutions and discusses similarities and differences of SC and OFDM systems and coexistence possibilities, and presents examples of SC-FDE performance capabilities.
Abstract: Broadband wireless access systems deployed in residential and business environments are likely to face hostile radio propagation environments, with multipath delay spread extending over tens or hundreds of bit intervals. Orthogonal frequency-division multiplex (OFDM) is a recognized multicarrier solution to combat the effects of such multipath conditions. This article surveys frequency domain equalization (FDE) applied to single-carrier (SC) modulation solutions. SC radio modems with frequency domain equalization have similar performance, efficiency, and low signal processing complexity advantages as OFDM, and in addition are less sensitive than OFDM to RF impairments such as power amplifier nonlinearities. We discuss similarities and differences of SC and OFDM systems and coexistence possibilities, and present examples of SC-FDE performance capabilities.

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Citations
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Book Chapter•DOI•
Antenna Diversity Techniques for SC/FDE — a System Analysis

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H. Witschnig, G. Strasser, K. Reich, Robert Weigel1, A. Springer •
University of Erlangen-Nuremberg1
01 Jan 2004
TL;DR: This work investigates the possibilities of combining diversity techniques with a Single Carrier System with Frequency Domain Equalization (SC/FDE), as future transmission concepts will also be judged by their possibilities to be combined with multiple antennas.
Abstract: In this work we investigate the possibilities of combining diversity techniques with a Single Carrier System with Frequency Domain Equalization (SC/FDE), as future transmission concepts will also be judged by their possibilities to be combined with multiple antennas. Concepts of multiple antennas allow either a significant performance gain through diversity (and) or significant higher capacity based on spatial multiplexing. While it is topic of many contributions to improve the concepts of antenna diversity itself, it is topic of this paper to point out the advantages when combining SC/FDE with diversity techniques. It will be demonstrated that SC/FDE shows excellent possibilities to be combined with diversity techniques, as the process of equalization itself can be combined with receive diversity as well as with space time block (STBC) decoding, that can be carried out advantageously in the frequency domain. Besides that an overall system approach will be discussed that includes aspects of implementation, equalization, modulation and coding.

3 citations

Proceedings Article•DOI•
A scheme for cancelling intercarrier interference using partial response encoding for MIMO-OFDM systems

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Yang Zhang1, Jiandong Li1, Lihua Pang1•
Xidian University1
01 Sep 2009
TL;DR: From the numerical results, PRC can effectively increase CIR and the improvement is proportional to the number of subcarriers and the coding length, and the effectiveness of PRC in mitigating ICI in MIMO-OFDM systems is demonstrated.
Abstract: Multiple-input multiple-output (MIMO) antennas combined with orthogonal frequency division multiplexing (OFDM) are very attractive for high data rate communications However, MIMO-OFDM systems are very vulnerable to time selective fading as channel time variation destroys the orthogonality among subcarriers, causing serious intercarrier interference (ICI) In this paper, we employ optimal frequency domain partial response coding (PRC) in MIMO-OFDM systems over frequency selective, fast fading channels to mitigate ICI We focus on deriving, via an analytical approach, a tractable, closed-form expression of carrier-to-interference ratio (CIR) to quantify the impact of time selective fading and demonstrate the effectiveness of PRC in mitigating ICI in MIMO-OFDM systems From the numerical results, PRC can effectively increase CIR and the improvement is proportional to the number of subcarriers and the coding length

3 citations

Dissertation•
Linear Amplification with Multiple Nonlinear Devices

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Vítor Hugo Soares Astúcia
01 Jan 2012
TL;DR: A method is proposed for designing the receiver that does not require a significant increase in system complexity and can be used for the computation of the receiver parameters for any constellation, implemented in the frequency-domain.
Abstract: In mobile wireless systems, where there are strict power and bandwidth constrains it is desirable to adopt energy efficient constellations combined with powerful equalizer. However, this increased spectral efficiency of multilevel modulations comes at the expense of reduced power efficiency, which is undesirable in systems where power consumption is a constraint. Hence, minimization of the transmitted energy would enable a significant reduction in the total energy consumption of the wireless mobile devices. A simple and practical constellation optimization design would optimize the transmitted energy with a minimum increase in system complexity. The constellation decomposition in terms of a sum of BPSK (Bi-Phase Shift Keying) sub-constellations, relies on an analytical characterization of the mapping rule were the constellation symbols are written as a linear function of the transmitted bits. Moreover, large constellations in general and non-uniform constellations in particular are very sensitive to interference, namely the residual ISI (Inter-Symbol Interference) at the output of a practical equalizer that does not invert completely the channel effects. IB-DFE (Iterative Block DFE) is a promising iterative frequency domain equalization technique for SC-FDE schemes (Single-Carrier with Frequency Domain Equalization) that allows excellent performance. Therefore it is possible to use the decomposition of constellations on BPSK components to define a pragmatic method for designing IB-DFE receivers that can be employed with any constellation. In this thesis we consider SC-DFE schemes based on high order M -ary energy optimized constellations with IB-DFE receivers. It is proposed a method for designing the receiver that does not require a significant increase in system complexity and can be used for the computation of the receiver parameters for any constellation. This method is then employed to design iterative receivers, implemented in the frequency-domain, which can cope with higher sensitivity to ISI effects of the constellations resulting from the energy optimization process.

3 citations

Cites background or methods from "Frequency domain equalization for s..."

  • ...Therefore the CP prevent the ISI for OFDM and SC-FDE schemes over multi-path channels and make the received blocks appear to be periodic....

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  • ...Single-Carrier with Frequency-Domain Equalization (SC-FDE) schemes [3] are excellent candidates for future broadband wireless systems since they can have good performance in severely time-dispersive channels without requiring complex receiver implementation [4, 5]....

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  • ...41 4.1 Cyclic prefix illustration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4.2 OFDM receiver structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 4.3 SC-FDE receiver structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 4.4 SC-FDE linear performance with 16-QAM and 16-Voronoi constellations ....

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  • ...A.1 Phase Imbalances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 A.2 Gain Imbalances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 List of Acronyms AWGN Additive White Gaussian Noise BER Bit Error Rate BPSK Bi-Phase Shift Keying CIR Channel Impulse Response CP Cyclic Prefix DFE Decision Feedback Equalization DFT Discrete Fourier Transform FDE Frequency-Domain Equalization FFT Fast Fourier Transform IB-DFE Iterative Block Decision Feedback Equalization IDFT Inverse Discrete Fourier Transform ISI Inter-Symbol Interference LLR Log-Likelihood Ratio LPF Low-Pass Filter MC Multi-Carrier MFB Matched Filter Bound MMSE Minimum Mean Square Error MSK Minimun-Shift Keying OFDM Orthogonal Frequency Division Multiplexing xv xvi LIST OF ACRONYMS OPAMP Operational Amplifier OQAM Offset Quadrature Amplitude Modulation OQPSK Offset Quadrature Phase Shift Keying PAM Pulse Amplitude Modulation PAPR Peak-to-Average Power Ratio PDP Power Delay Profile PDF Probability Density Function PSD Power Spectral Density QAM Quadrature Amplitude Modulation QoS Quality of Service QPSK Quadrature Phase Shift Keying SC Single-carrier SC-FDE Single-Carrier with Frequency-Domain Equalization SER Symbol Error Rate SINR Signal-to-Interference plus Noise Ratio SNR Signal-to-Noise Ratio ZF Zero-Forcing List of Symbols ai amplitude values from PAM signal an n th correspondent bits apn nth correspondent bits in the parallel format asn n th correspondent bits in the series format aIn n th in-phase correspondent bits aQn nth quadrature correspondent bits bi amplitude values from PAM signal Bk feedback equalizer coefficient for the kth frequency b (m) n mth associated bit to the nth time-domain data symbol (-1 or 1) b (m) n "hard-decisions" mth associated bit to the nth time-domain data symbol b eq(m) n represents ( b (m) n )γm,i d minimum Euclidean distance ds̃n,s normalized distance between s̃n and s E0 energy of minimum amplitude symbol Epeak peak energy Eb average bit energy Es average symbol energy fc carrier frequency Fk feedforward equalizer coefficient for the kth frequency G gain Gp Gray penalty xvii xviii LIST OF SYMBOLS gm m th gain coefficient Hk overall channel frequency response for kth frequency k frequency index M constellation size N number of symbols/subcarriers Nk channel noise for the kth frequency No noise power spectral density (unilateral) p(t) modulation pulse after the match filter Pb bit error probability Ps symbol error probability Q Gaussian tail function r(t) modulation pulse rp modulation pulse in parallel format rs modulation pulse in series format s(t) time-domain data symbol sI continuous in-phase component sQ continuous quadrature component si i th continuous data symbol Ŝk estimate for kth frequency-domain data symbol Sk k th frequency-domain data symbol S̃k "hard-decisions" for kth frequency-domain data symbol Sk "soft-decisions" for kth frequency-domain data symbol sn n th discrete data symbol sIn discrete in-phase signal component sQn discrete quadrature signal component ŝn estimate for nth time-domain data symbol s̃n "hard-decisions" for nth time-domain data symbol sn "soft-decisions" for nth time-domain data symbol spn time-domain signal in parallel format ssn time-domain signal in series format T symbol time duration xix xp modulated signal in parallel format xs modulated signal in series format xI modulated in-phase signal xQ modulated quadrature signal xBP transmitted signal y(t) signal after the match filter yk sampled signal after the match filter Yk received sample for the kth frequency β (m) n mth associated bit to the nth time-domain data symbol (0 or 1) ∆ normalized Gilbert distance γµ,i binary representation of i λ (m) n log-likelihood of the mth bit for the nth data symbol g gains matrix s constellation symbols matrix W Hadamard matrix S set of constellation symbols φi i th basis function Ψ (m) i subsets of G where β (m) n = i ρ correlation coefficient ρ (m) n correlation coefficient of mth symbol for nth time-domain data symbol σ2N variance of channel noise σ2S variance of the transmitted frequency-domain symbols xx LIST OF SYMBOLS List of Figures 2.1 Orthogonal signals in Square-Quadrature Amplitude Modulation (QAM)....

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  • ...Orthogonal Frequency Division Multiplexing (OFDM) has become popular and widely used in many wireless systems operating in the frequency-selective fading radio channel....

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Journal Article•DOI•
Uplink Capacity of A Cellular System Using Multi-user Single-carrier MIMO Multiplexing Combined with Frequency-domain Equalization and Transmit Power Control

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Takahiro Chiba1, Kazuaki Takeda1, Kazuki Takeda1, Fumiyuki Adachi1•
Tohoku University1
01 Jun 2011-Wireless Personal Communications
TL;DR: Frequency-domain zero-forcing detection (ZFD) and frequency-domain minimum mean square error detection (MMSED) are considered for MU signal detection and it is shown that ZFD and MMSED provide almost the same uplink capacity and that an advantage of fast TPC over slow TPC diminishes.
Abstract: Multi-user single-carrier multiple-input multiple-output (MU SC-MIMO) multiplexing can increase the uplink capacity of a cellular system without expanding the signal bandwidth. It is practically important to make clear an extent to which the MU SC-MIMO multiplexing combined with frequency-domain equalization (FDE) and transmit power control (TPC) can increase the uplink capacity in the presence of the co-channel interference (CCI). Since the theoretical analysis is quite difficult, we resort to the computer simulation to investigate the uplink capacity. In this paper, frequency-domain zero-forcing detection (ZFD) and frequency-domain minimum mean square error detection (MMSED) are considered for MU signal detection. It is shown that ZFD and MMSED provide almost the same uplink capacity and that an advantage of fast TPC over slow TPC diminishes. As a result, MU SC-MIMO using computationally efficient ZFD can be used together with slow TPC instead of using MMSED. With 8 receive antennas and slow TPC, MU SC-MIMO multiplexing using ZFD can achieve about 1.5 times higher uplink capacity than SU SC-SIMO diversity.

3 citations

Proceedings Article•DOI•
Non-binary coded CCSK and Frequency-Domain Equalization with simplified LLR generation

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Oussama Abassi, Laura Conde-Canencia, Mohammad M. Mansour1, Emmanuel Boutillon•
American University of Beirut1
08 Sep 2013
TL;DR: It is demonstrated that Maximum Likelihood (ML) demodulation can be expressed by two circular convolution operations and thus it can be processed in the frequency domain and a joint Frequency-Domain Equalization (FDE) and LLR generation scheme that aims at reducing the complexity of the receiver is proposed.
Abstract: In this paper, we investigate the performance of Single-Carrier (SC) transmission with Non-Binary Low-Density Parity-Check (NB-LDPC) coded Cyclic Code-Shift Keying (CCSK) signaling in a multipath environment and we show that the combination of CCSK signaling and non-binary codes results in two key advantages, namely, improved Log-Likelihood Ratio (LLR) generation via correlations and reduced implementation complexity. We demonstrate that Maximum Likelihood (ML) demodulation can be expressed by two circular convolution operations and thus it can be processed in the frequency domain. Then, we propose a joint Frequency-Domain Equalization (FDE) and LLR generation scheme that aims at reducing the complexity of the receiver. Finally, we demonstrate through Monte-Carlo simulations and histogram analysis that this proposed CCSK signaling scheme gives more robustness to SC-FDE systems than commonly employed Hadamard signaling schemes (a gap of ≈ 1.5dB in favor of CCSK signaling is observed at BER = 10-5, assuming perfect Channel State Information).

3 citations

Cites methods from "Frequency domain equalization for s..."

  • ...SC-FDE is a single carrier transmission scheme used to mitigate the ISI while avoiding the drawbacks of OFDM [10]....

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References
More filters
Book•
Adaptive Filter Theory

[...]

Simon Haykin
01 Jan 1986
TL;DR: In this paper, the authors propose a recursive least square adaptive filter (RLF) based on the Kalman filter, which is used as the unifying base for RLS Filters.
Abstract: Background and Overview. 1. Stochastic Processes and Models. 2. Wiener Filters. 3. Linear Prediction. 4. Method of Steepest Descent. 5. Least-Mean-Square Adaptive Filters. 6. Normalized Least-Mean-Square Adaptive Filters. 7. Transform-Domain and Sub-Band Adaptive Filters. 8. Method of Least Squares. 9. Recursive Least-Square Adaptive Filters. 10. Kalman Filters as the Unifying Bases for RLS Filters. 11. Square-Root Adaptive Filters. 12. Order-Recursive Adaptive Filters. 13. Finite-Precision Effects. 14. Tracking of Time-Varying Systems. 15. Adaptive Filters Using Infinite-Duration Impulse Response Structures. 16. Blind Deconvolution. 17. Back-Propagation Learning. Epilogue. Appendix A. Complex Variables. Appendix B. Differentiation with Respect to a Vector. Appendix C. Method of Lagrange Multipliers. Appendix D. Estimation Theory. Appendix E. Eigenanalysis. Appendix F. Rotations and Reflections. Appendix G. Complex Wishart Distribution. Glossary. Abbreviations. Principal Symbols. Bibliography. Index.

16,062 citations

"Frequency domain equalization for s..." refers methods in this paper

  • ...Adaptation can be done with LMS (least mean square), RLS, or least squares minimization (LS) techniques, analogous to adaptation of time domain equalizers [Hay96], [Cla98]....

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  • ...Overlap-save or overlap-add signal processing techniques could also be used to avoid the extra overhead of the cyclic prefix [Fer85], [Hay96]....

    [...]

Journal Article•DOI•
Analysis and Simulation of a Digital Mobile Channel Using Orthogonal Frequency Division Multiplexing

[...]

Jr. L.J. Cimini1•
Bell Labs1
01 Jul 1985-IEEE Transactions on Communications
TL;DR: The analysis and simulation of a technique for combating the effects of multipath propagation and cochannel interference on a narrow-band digital mobile channel using the discrete Fourier transform to orthogonally frequency multiplex many narrow subchannels, each signaling at a very low rate, into one high-rate channel is discussed.
Abstract: This paper discusses the analysis and simulation of a technique for combating the effects of multipath propagation and cochannel interference on a narrow-band digital mobile channel. This system uses the discrete Fourier transform to orthogonally frequency multiplex many narrow subchannels, each signaling at a very low rate, into one high-rate channel. When this technique is used with pilot-based correction, the effects of flat Rayleigh fading can be reduced significantly. An improvement in signal-to-interference ratio of 6 dB can be obtained over the bursty Rayleigh channel. In addition, with each subchannel signaling at a low rate, this technique can provide added protection against delay spread. To enhance the behavior of the technique in a heavily frequency-selective environment, interpolated pilots are used. A frequency offset reference scheme is employed for the pilots to improve protection against cochannel interference.

2,627 citations

"Frequency domain equalization for s..." refers background in this paper

  • ...OFDM transmits multiple modulated subcarriers in parallel [ 1 ]....

    [...]

  • ...Several variations of orthogonal frequency-division multiplexing (OFDM) have been proposed as effective anti-multipath techniques, primarily because of the favorable trade-off they offer between performance in severe multipath and signal processing complexity [ 1 ]....

    [...]

Book•
Adaptive filter theory (2nd ed.)

[...]

Simon Haykin1•
McMaster University1
01 Mar 1991

2,447 citations

Journal Article•DOI•
BER sensitivity of OFDM systems to carrier frequency offset and Wiener phase noise

[...]

Thierry Pollet1, M. Van Bladel1, Marc Moeneclaey1•
Ghent University1
01 Feb 1995-IEEE Transactions on Communications
TL;DR: In this contribution the transmission of M-PSK and M-QAM modulated orthogonal frequency division multiplexed (OFDM) signals over an additive white Gaussian noise (AWGN) channel is considered and the degradation of the bit error rate is evaluated.
Abstract: In this contribution the transmission of M-PSK and M-QAM modulated orthogonal frequency division multiplexed (OFDM) signals over an additive white Gaussian noise (AWGN) channel is considered. The degradation of the bit error rate (BER), caused by the presence of carrier frequency offset and carrier phase noise is analytically evaluated. It is shown that for a given BER degradation, the values of the frequency offset and the linewidth of the carrier generator that are allowed for OFDM are orders of magnitude smaller than for single carrier systems carrying the same bit rate. >

1,816 citations

Journal Article•DOI•
Polyphase codes with good periodic correlation properties (Corresp.)

[...]

D. Chu1•
Hewlett-Packard1
01 Jul 1972-IEEE Transactions on Information Theory
TL;DR: This correspondence describes the construction of complex codes of the form exp i \alpha_k whose discrete circular autocorrelations are zero for all nonzero lags.
Abstract: This correspondence describes the construction of complex codes of the form exp i \alpha_k whose discrete circular autocorrelations are zero for all nonzero lags. There is no restriction on code lengths.

1,624 citations

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