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Journal ArticleDOI

Frequency domain equalization for single-carrier broadband wireless systems

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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Journal ArticleDOI
Peng Sun1, Fei Liu1, Cui Jianhua, Wei Wang1, Yangdong Ye1, Zhongyong Wang1 
27 Mar 2020-Sensors
TL;DR: Numerical results show that the proposed joint scheme can achieve significant performance gain, and demonstrate the effectiveness in dealing with the nonlinear distortion from few-bit ADC.
Abstract: Few-bit analog-to-digital converter (ADC) is regarded as a promising technique to greatly reduce power consumption of Internet of Things (IoT) devices in millimeter-wave (mmWave) communications. In this work, based on the recently proposed parametric bilinear generalized approximate message passing (PBiGAMP), we propose a new scheme to perform joint symbol detection, channel estimation and decoding. The proposed scheme is flexible to deal with discrete prior on symbols, Gaussian mixture prior on channels and quantized likelihood on observations. Furthermore, we introduce doping factor to control the portion of “extrinsic” and “posterior” information with negligible complexity increase. Since this joint scheme can be implemented via fast Fourier transformation (FFT), the complexity grows only logarithmically. Compared to the benchmark algorithms, numerical results show that the proposed joint scheme can achieve significant performance gain, and demonstrate the effectiveness in dealing with the nonlinear distortion from few-bit ADC.

2 citations


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

  • ...Abbreviations The following abbreviations are used in this manuscript: LTE Long Term Evolution ADC analog-to-digital PBiGAMP Parameteric bilinear generalized approximate message passing OFDM orthogonal frequency division multiplexing SC single-carrier FDE frequency domain equalization GAMP generalized approximate message passing VAMP vector approximate message passing MIMO multiple input multiple output PCSI perfect channel state information FFT fast Fourier transform pdf probability density function pmf probability mass function VGA variable gain amplifier AGC automatic gain control RF radio frequency BP belief propagation SPA sum-product algorithm MSE mean square error AWGN additive white Gaussian noise GMM Gaussian mixture model SISO soft-input and soft-output LDPC low-density parity-check MMSE minimum mean square error LMMSE linear minimum mean square error BER bit error rate NMSE normalized mean square error...

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  • ...Compared to orthogonal frequency division multiplexing (OFDM) [5], single-carrier (SC) with frequency domain equalization (FDE) [6,7] has similar performance and complexity but much lower PAPR, which relaxes requirements on power-amplifier linearity and thus enables the use of more efficient and cheaper amplifiers....

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Journal ArticleDOI
TL;DR: The frequency domain signal-to-interference-plus-noise-ratio (SINR) after weight control is investigated and the computational complexity of the proposed receiver is analyzed.

2 citations

Patent
08 Mar 2018
TL;DR: In this paper, a frequency-domain equalization circuit, a noise-whitening filter and a noise predictor are used to provide signal equalization in the frequency domain by converging on symbols of the input signal.
Abstract: Signal equalization is provided, according to certain aspects, by a frequency-domain equalization circuit, a noise-whitening filter and a noise predictor. A sequencer is used to control ordering of the equalization circuit, a noise-whitening filter and a noise predictor. The equalization circuit provides equalization the frequency domain by converging on symbols of the input signal. The noise-whitening filter and the noise predictor filter colored noise from a signal responsive to the equalization circuit. The sequencer controls operation of the noise-whitening filter by detecting an indication of convergence of the symbols from input signal and causing the noise-whitening filter to commence suppression of colored noise from a signal derived from an output by the equalization circuit.

2 citations

Proceedings ArticleDOI
01 Sep 2009
TL;DR: It has been observed that the proposed structure exploits the multi-path diversity sources of the channel effectively and a performance very close to MIMO-OFDM outage probability can be achieved, so the proposed iterative SC-FDE technique can be viewed as a strong alternative to M IMO- OFDM schemes with similar complexity.
Abstract: Single carrier frequency domain equalization (SC-FDE) is receiving considerable attention recently due to its comparable complexity and performance with OFDM. In this paper, an iterative SC-FDE with decision feedback in frequency domain is proposed for wideband multiple-input multiple-output (MIMO) channels and more general multipath vector channels as a generalization of previous works considering FDE with decision feedback for single-input single-output (SISO) systems. The proposed detector is based on iterative forward and backward filtering followed by a MIMO multi-stream detector that uses a priori log-likelihood ratios (LLR) of coded symbols. Forward and feedback filters are jointly optimized according to the minimum mean square error (MMSE) criterion to minimize both self inter-symbol-interference (ISI) and interference from other streams transmitted at different antennas. It has been observed that the proposed structure exploits the multi-path diversity sources of the channel effectively and a performance very close to MIMO-OFDM outage probability can be achieved. Therefore, our proposed iterative SC-FDE technique for MIMO wideband channels can be viewed as a strong alternative to MIMO-OFDM schemes with similar complexity.

2 citations


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

  • ...Since OFDM suffers from high peak-to-average power ratio (PAPR) problem, SC techniques leading to more efficient use of power amplifiers are more suitable for uplink channels [1], [2]....

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  • ...It has been shown in [1] that frequency domain equalization (FDE) can readily be applied to SC transmission to yield similar performance to OFDM....

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Proceedings ArticleDOI
01 Sep 2006
TL;DR: A frequency domain equalizer (FEQ) without cyclic prefix for single carrier system is proposed and the cancellation of the inter-block interference and inter-carrier interference are cancelled based on the proposed iterative interference cancellation.
Abstract: Recently, the growing popularity of low-complexity multi-carrier modulation techniques, such as orthogonal frequency division multiplexing (OFDM), has led researchers to consider equalization of single carrier (SC) transmissions in the frequency domain. However, existing frequency domain equalizers for single carrier modulation rely on the introduction of a cyclic prefix (CP), which are usually not available in the conventional SC based communications standards. In this paper, a frequency domain equalizer (FEQ) without cyclic prefix for single carrier system is proposed. An interference analysis is presented for the block equalization of SC system without CP. The cancellation of the inter-block interference and inter-carrier interference are based on the proposed iterative interference cancellation. The proposed equalizer and the subsequent analysis are also verified through numerical simulations.

2 citations

References
More filters
Book
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]....

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Journal ArticleDOI
Jr. L.J. Cimini1
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 ]....

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  • ...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 ]....

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Book
Simon Haykin1
01 Mar 1991

2,447 citations

Journal ArticleDOI
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 ArticleDOI
D. Chu1
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