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.
Citations
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01 Apr 2007
TL;DR: This work applies the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept, and obtains a power and bandwidth efficient broadband technique for the SISO and MIMO multipath channels.
Abstract: Correlative minimum shift keying (MSK), a second order polynomial modulation scheme known as tamed frequency modulation (TFM), is a constant envelope type of modulation with a perfect peak to average power ratio (PAPR), besides the property of low out of band power. We apply the linearized TFM to the single carrier transmission with frequency domain equalization (SC/FDE) concept. We then obtain a power and bandwidth efficient broadband technique for the SISO and MIMO multipath channels. Finally we present simulation results.
3 citations
Additional excerpts
...SC/FDE has been an emerging technique in the last years, its performance is proved to be similar to OFDM [1] [2]....
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Proceedings Article•
01 Jan 2014TL;DR: This paper introduces the frequency domain equalization technique with the maximum ratio combining, zero forcing and Minimum Mean Square Error (MMSE) filters and shows that the proposed system with the MMSE filter owing to the diversity effect outperforms the conventional one.
Abstract: In this paper, we propose a new Cyclic Prefix (CP) design for Orthogonal Frequency Division Multiplexing (OFDM) system with higher tranmission efficiency. The proposed signal design concatenates some OFDM symbols without guard interval and adds one CP per the concatenated symbols. Obviously, the proposed CP design results in severe inter-symbol-interference and inter-carrier-interference when we apply the conventional OFDM demodulation to the received signal. In order to combat them, we introduce the frequency domain equalization technique with the maximum ratio combining, zero forcing and Minimum Mean Square Error (MMSE) filters. By computer simulations, we show that the proposed system with the MMSE filter owing to the diversity effect outperforms the conventional one.
3 citations
Cites methods from "Frequency domain equalization for s..."
...Frequency Domain Equalization (FDE) applied to the SC systems has received attention in next wireless access systems by being motivated by the one-tap equalization of the OFDM systems [3], [4]....
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04 Dec 2007
TL;DR: The frequency domain derivation of a generalized minimum mean square error turbo equalizer for orthogonal space-time block code per block for multiple-input multiple-output communication system with single-carrier modulation and frequency domain equalization is proposed.
Abstract: This paper deals with multiple-input multiple-output communication system with single-carrier modulation and frequency domain equalization. Space-time coding schemes adapted to frequency-selective channels namely space-time block codes per block are used. An efficient generalized receiver based on space-time frequency domain detector is investigated. We propose the frequency domain derivation of a generalized minimum mean square error turbo equalizer for orthogonal space-time block code per block. The main advantage of our proposed scheme is that it can be applied to any orthogonal space-time block code per block. Simulation results show that the scheme performs efficiently over frequency-selective block fading channels.
3 citations
Cites background from "Frequency domain equalization for s..."
...16 introduces the use of techniques to avoid the inter-symbol interference (ISI) due to multipath propagation like orthogonal frequency division multiplexing modulation (OFDM) or single-carrier modulation with frequency domain equalization [1] (SC-FDE)....
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01 Jan 2005
TL;DR: This paper uses the use of a unit-tap constraint to manipulate existing algorithms into a framework analogous to the recursive least squares algorithm, and develops adaptation rules for blind and semi-blind frequency domain equalizers for SCCP receivers.
Abstract: Orthogonal frequency division multiplexing (OFDM) is a popular transmission format for emerging wireless communication systems. Single-carrier cyclic-prefixed (SCCP) modulation is similar to OFDM, but with all frequency-domain operations performed at the receiver. Systems employing OFDM and SCCP perform well in the presence of multipath provided that the channel delay spread is shorter than the guard interval between transmitted blocks. If this condition is not met, a channel shortening equalizer can be used. Existing adaptive channel shorteners require re-normalization to restrain the channel shortener away from zero. In this paper, we study the use of a unit-tap constraint rather than a unit-norm constraint. We use this constraint to manipulate existing algorithms into a framework analogous to the recursive least squares algorithm, and we develop adaptation rules for blind and semi-blind frequency domain equalizers for SCCP receivers. Simulations show an order of magnitude improvement in convergence speed and reduced asymptotic bit error rate
3 citations
Cites background from "Frequency domain equalization for s..."
...A related emerging modulation format is single-carrier cyclic-prefixed (SCCP) modulation [1], [2], also known as single-carrier frequency-domain equalization...
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08 Nov 2012
TL;DR: This paper proposes an excess-bandwidth joint transmit/receive FDE, using minimum mean-square error based frequency-domain equalization at the receiver to combat the problem of inter-symbol interference (ISI) arising from channel frequency-selectivity.
Abstract: Abstract A modification of transmit filtering in single-carrier (SC) transmission contributes to an improvement of system performance in terms of peak-to-average power ratio (PAPR) and bit error rate (BER). Using minimum mean-square error based frequency-domain equalization (MMSE-FDE) at the receiver can combat the problem of inter-symbol interference (ISI) arising from channel frequency-selectivity. In this paper, instead of conventional transmit and receive filters, we propose an excess-bandwidth joint transmit/receive FDE. Transmit FDE weight (Tx-FDE) is determined jointly with receive FDE (Rx-FDE) in a suboptimal approach. Excess-bandwidth transmit filtering also leads to the additional frequency diversity gain when MMSE-FDE with spectrum combining is used at the receiver. Performance evaluation of the proposed transmission scheme is shown in terms of PAPR, BER, and system throughput, with the variation of transmit roll-off factor. Keyword Single-carrier (SC) transmission, transmit filter, frequency-domain equalization (FDE)
3 citations
Cites background from "Frequency domain equalization for s..."
...[6] K. Takeda, H. Tomeba, and F. Adachi, “Multicode DS-CDMA using Joint Transmit/Receive MMSE-FDE,” Proc....
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...Joint transmit/receive MMSE-FDE (joint Tx/Rx MMSE-FDE) [6], [7], whose FDE weights are jointly calculated based on MMSE criterion, is introduced as a good method to reduce residual ISI with lower computational complexity....
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...We also compare the BER performance of transmission using joint Tx/Rx MMSE-FDE with the one using square-root raised cosine filter [11]....
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...Although MMSE-FDE is able to improve the BER performance [5], the performance is still far from matched-filter bound....
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...On the other hand, single-carrier (SC) transmission [3] provides lower PAPR than OFDM, while using minimum mean-square error based frequency-domain equalization (MMSE-FDE) [4] can combat with ISI....
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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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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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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
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