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Journal Article•DOI•

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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Proceedings Article•DOI•
30 Nov 2009
TL;DR: The proposed MSK modulation provides SC-OFDM system immunity to ICI and significantly outperforms SC-TODM system and OFDM system with Phase Shift Keying (PSK) modulations in severe ICI environment.
Abstract: SC-OFDM (single carrier orthogonal frequency division multiplexing) has demonstrated excellent performance in multipath fading channels with very low peak to average power ratio (PAPR). Similar to other multi-carrier transmission technologies such as MC-CDMA and OFDM, SC-OFDM also suffers significant performance degradation to inter-carrier interference (ICI) when there is a frequency offset between the transmitter and receiver or in a high mobility environment. In this paper, we analyze the effect of ICI on SC-OFDM system and propose a novel modulation scheme called Magnitude Shift Keying (MSK) for SC-OFDM system. The MSK modulation provides SC-OFDM system immunity to ICI and significantly outperforms SC-OFDM system and OFDM system with Phase Shift Keying (PSK) modulations in severe ICI environment. Simulation results over AWGN channel and multi-path fading channels with different ICI confirm the effectiveness of the proposed system.

12 citations


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

  • ...For example, single carrier transmission with frequency domain equalization (SCFDE) [2][3][4][5] or carrier interferometry orthogonal frequency division multiplexing (CI/OFDM) [6][7][8] are essentially the same technology by combining the benefit of multicarrier transmission and single carrier…...

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Journal Article•DOI•
TL;DR: An iterative channel estimation that uses pilot chips which are time-multiplexed within each chip block for fast Fourier transform (FFT) and it is shown that the proposed channel estimation has a very good tracking ability against fast fading.
Abstract: As the channel frequency selectivity becomes severer, the bit error rate (BER) performance of direct sequence spread spectrum (DSSS) signal transmission with rake combining degrades due to an increasing inter-path interference (IPI). Frequency-domain equalization (FDE) can replace rake combining with much improved BER performance in a severe frequency-selective fading channel. For FDE, accurate estimation of the channel transfer function is required. In this paper, we propose an iterative channel estimation that uses pilot chips which are time-multiplexed within each chip block for fast Fourier transform (FFT). The pilot acts as a cyclic-prefix of FFT block as well. The achievable BER performance is evaluated by computer simulation. It is shown that the proposed channel estimation has a very good tracking ability against fast fading.

12 citations


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

  • ...It is shown that the proposed channel estimation has a very good tracking ability against fast fading. key words: DSSS, frequency-domain equalization (FDE), channel estimation...

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Proceedings Article•DOI•
01 Nov 2010
TL;DR: In this article, the authors presented the theoretical analysis of the BER performance achievable with overlap FDE by taking into account the residual inter-block interference (IBI), and derived the conditional BER for the given set of channel gains.
Abstract: In the single-carrier (SC) transmission, minimum mean square error frequency-domain equalization (MMSE-FDE) can achieve a good bit error rate (BER) performance in a frequency-selective fading channel The conventional FDE requires the insertion of cyclic prefix (CP) to make the received signal block to be a circular convolution of the transmit signal and the channel Overlap FDE requires no CP insertion However, its BER performance improvement is limited by the residual inter-block interference (IBI) In this paper, we present the theoretical analysis of the BER performance achievable with overlap FDE by taking into account the residual IBI after overlap FDE Then, by using the Gaussian approximation of the residual IBI as well as the residual inter-symbol interference (ISI), we derive the conditional BER for the given set of the channel gains The average BER performance is numerically evaluated

12 citations


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

  • ...The use of minimum mean square error frequency-domain equalization (MMSE-FDE) can take advantage of the channel frequency-selectivity and achieve a good bit error rate (BER) performance [3]-[5]....

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Proceedings Article•DOI•
05 Nov 2012
TL;DR: The proposed hybrid time-frequency domain equalization method for pseudorandom noise (PN) based single-carrier block transmissions includes two parts: a multi-channel frequency domain equalizer and a single channel adaptive time domain decision feedback equalizer (DFE).
Abstract: Single-carrier block transmission (SCBT) has a great potential for providing higher bandwidth efficiency over frequency-selective channels with reduced computational complexity and low peak-to-average power ratio (PAPR). In this paper we propose a hybrid time-frequency domain equalization method for pseudorandom noise (PN) based single-carrier block transmissions. The proposed hybrid time-frequency domain equalizer includes two parts: a multi-channel frequency domain equalizer and a single channel adaptive time domain decision feedback equalizer (DFE). Bidirectional DFE and time-reversal diversity processing to cancel both residual post-cursor and pre-cursor intersymbol interference (ISI) is extended to hybrid time-frequency domain equalizer.Underwater acoustic communication systems with single transmitter and multiple receivers have been designed and tested in lake in 2011. At a distance of 1.8 km, the useful data rates around 1500-7000 bps were achieved with uncoded bit error rate (BER) 10--3-10--5 using the presented schemes. Experiment shows the performance can be enhanced by 1.5-3.8 dB in terms of output signal-to-noise ratio (SNR). A sea experiment was conducted with single transmitter and single receiver in 2012. At a distance of 625 m, the useful data rates around 8750 bps were achieved with uncoded bit error rates 10--2-10--3 using the presented schemes. Experiment shows the performance can be enhanced by 1.6-2 dB in terms of output SNR.

12 citations

Proceedings Article•DOI•
09 Nov 2010
TL;DR: This paper proposes to combine OFDM/OQAM with Frequency Division Multiple Access (FDMA) to get an alternative to the well-known Orthogonal Frequency Division multiple access techniques for the uplink (UL) transmission in the 3GPP/LTE context and names this alternative OQAMA.
Abstract: Nowadays, OFDM/OQAM is considered as an attractive alternative to conventional OFDM with cyclic prefix (CP) for transmission over doubly dispersive channels. By using well designed pulse shapes and removing the CP, OFDM/OQAM has the advantage of a higher spectral efficiency. In this paper, we propose to combine OFDM/OQAM with Frequency Division Multiple Access (FDMA) to get an alternative to the well-known Orthogonal Frequency Division Multiple Access (OFDMA) and to Single Carrier Frequency Division Multiple Access (SC-FDMA) techniques for the uplink (UL) transmission in the 3GPP/LTE context. For concision purpose, this proposed alternative is named OQAMA. The performances of the OQAMA technique are evaluated and compared with the OFDMA and SC-FDMA ones. The results demonstrate the efficiency of OQAMA over a Doppler spread channel within 3GPP/LTE standard.

12 citations


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

  • ...Its main principle is the same as for OFDM, thus the same benefits in terms of multipath mitigation and low complexity equalization are achievable [8]....

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  • ...On the other hand, when DFT de-spreading is performed at the receiver, the noise is spread over all the subcarriers and generates a noise enhancement, which degrades the SCFDM performance and requires the use of a more complex one-tap equalization based on a Minimum Mean Square Error (MMSE) receiver [8]....

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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 Article•DOI•
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 Article•DOI•
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•
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