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 Aug 2013
TL;DR: In this article, the principle and experiments of coherent optical Nyquist single carrier frequency domain equalization (SCFDE) systems are discussed and nonlinear compensation for terabit Nyquist super-channel transmission are reviewed.
Abstract: The Nyquist wavelength division multiplexing (Nyquist-WDM) technology has aroused great interests for its high spectrum efficiency (SE) by narrowing down the bandwidth in each channel without introducing inter-symbol-interference (ISI). In this paper, we discuss the principle and experiments of coherent optical Nyquist single carrier frequency domain equalization (SCFDE) systems. Terabit Nyquist super-channel transmission and nonlinear compensation are reviewed.
11 May 2008
TL;DR: Simulation results show in a typical urban channel that the bit-error-rate (BER) performance of the WSB- FDE is superior to that of the RLS-FDE as the STBC-like matrix- wise block length increases.
Abstract: In this paper, a weighted space-time block-coding (STBC)-like matrix-wise block adaptive frequency-domain equalization (WSB-FDE), which has a flexibility over the STBC-like matrix-wise block length as compared to a normalized least- mean-square (NLMS)-FDE and a recursive-least-square (RLS)- FDE, is proposed for the cyclic-prefixed STBC single-carrier systems equipped with a diversity combining. In the WSB-FDE, the STBC-like matrix-wise block is first formulated from received blocks. The correction terms of the equalizer coefficients in each block are then updated so as to minimize a weighted squared- norm of the a posteriori error vector for the formulated block. Moreover, a square-root adaptive algorithm based on an unitary Givens rotations is proposed to achieve the numerical stability and computational efficiency in update procedure of the WSB- FDE. Finally, simulation results show in a typical urban (TU) channel that the bit-error-rate (BER) performance of the WSB- FDE is superior to that of the RLS-FDE as the STBC-like matrix- wise block length increases.
Cites background from "Frequency domain equalization for s..."
...Minimum-mean-square-error frequency-domain equalization (MMSE-FDE) of single-carrier (SC) system with a cyclicprefix (CP) has been expected to be an alternative scheme to the time-domain equalization (TDE) and orthogonal frequency division multiplexing (OFDM) system due to its low computational complexity and peak-to-average ratio (PAR), respectively [1]....
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Journal Article•
Patent•
20 Dec 2006TL;DR: In this article, a method for receiving a pilot symbol in a single carrier frequency division multiple access, SC-FDMA, receiver (400) is presented. But the method is not suitable for the case of single-input single-out (SISO) channels.
Abstract: A method for receiving a pilot symbol in a single carrier frequency division multiple access, SC-FDMA, receiver (400). In a first step (806), a cyclic prefix is removed from a received sequence to produce a modified sequence (808); the modified sequence is then transformed in a second step (810) to a first frequency domain sequence according to a first transform. In a third step (812), a plurality of distributed subcarriers in the transformed modified sequence are demapped in order to extract a plurality of received pilot symbols. An intermediate channel estimate for each of the plurality of received pilot symbols is derived based on one or more characteristics of each of the plurality of pilot symbols in a further step (814). In a final step (816), interpolation is performed on the intermediate channel estimates to obtain final channel estimates.
References
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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