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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TL;DR: Recent advances in various distributed multi-input/multi-output (MIMO) techniques combined with single-carrier (SC) frequency-domain signal processing are presented for DAN, with particular attention paid to SC frequency- domain MIMO diversity, relay, beamforming, and multiplexing jointly used with frequency- domains equalization (FDE).
Abstract: For gigabit wireless data services, there are three important technical issues to be addressed: limited bandwidth, severe frequency-selective fading, and limited transmit power. A distributed antenna network (DAN) is a promising solution to the above three technical issues. In DAN, each mobile user is served by using multiple distributed antennas close to it. In this paper, recent advances in various distributed multi-input/multi-output (MIMO) techniques combined with single-carrier (SC) frequency-domain signal processing are presented for DAN. Particular attention is paid to SC frequency-domain MIMO diversity, relay, beamforming, and multiplexing jointly used with frequency-domain equalization (FDE) to significantly improve the signal transmission performance.
8 citations
TL;DR: An iterative interfrequency interference cancellation method for the time-varying multipath channels over one SC-FDE symbol and partial minimum-mean-square-error equalization to improve the accuracy of the estimation is put forward.
Abstract: This paper considers a novel virtual pilot-assisted channel estimation algorithm for multiple input multiple output single carrier frequency domain equalization (MIMO-SCFDE) systems over fast time-varying multipath channels. Given that the fast time-varying channels can no longer support the assumption that the channel frequency-domain response remains invariant for the duration of one SC-FDE symbol, most of the channel estimation methods cannot be directly applied to MIMO-SCFDE systems. We put forward an iterative interfrequency interference cancellation method for the time-varying multipath channels over one SC-FDE symbol. The proposed method utilizes the virtual pilot-assisted channel estimation and partial minimum-mean-square-error equalization to improve the accuracy of the estimation. Simulation results validate the improved performance of the proposed method for MIMO-SCFDE systems over fast time-varying multipath channels.
8 citations
Cites background from "Frequency domain equalization for s..."
...The multipath channel causes a time dispersion of the transmitted signal, resulting in the overlap of the various transmitted symbols at the receiver [5], [6], which is referred to as intersymbol interference (ISI)....
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TL;DR: The simulation results show that the equalization performance of NP-BI is better than the frequency-domain equalization with NP (FDE-NP) and the computational complexity of NP -BI is lower than FDE- NP.
Abstract: In this paper, the block-iterative decision feedback equalizer with noise prediction (NP-BI) is introduced for single-carrier (SC) multiple-input-multiple-output (MIMO) transmission. In NP-BI, the decision feedback equalization can be realized in the frequency domain, and the equalizer coefficients can be easily calculated from the frequency-domain channel response. In addition, the proposed NP-BI can be well combined with the spatial precoding performed at the transmitter. The analysis shows that only one spatial precoding matrix is needed during one data block transmission. Therefore, the channel state information feedback for the transmitter precoding is very small. The simulation results show that the equalization performance of NP-BI is better than the frequency-domain equalization with NP (FDE-NP). In addition, the computational complexity of NP-BI is lower than FDE-NP.
8 citations
Cites background from "Frequency domain equalization for s..."
...Recently, single-carrier transmission with frequency-domain equalization (SC-FDE) has become an attractive wireless transmission technology [1]–[4]....
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...It is shown in [1]–[3] that SC-FDE exhibits comparable performance with the same equalization complexity as OFDM....
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01 Dec 2005
TL;DR: The proposed generalized cyclic prefixed (GCP) communication system provides an additional degree of freedom that allows trade-offs among peak-to-average power ratio (PAR), bit allocation capability, and frequency diversity.
Abstract: This paper describes a cyclic prefixed communication structure that is a generalization of both the orthogonal frequency-division multiplexing (OFDM) system and the cyclic prefixed single-carrier (CP-SC) system. By exploiting the fact that a circulant matrix (CM) is also a block circulant matrix (BCM), the proposed generalized cyclic prefixed (GCP) communication system provides an additional degree of freedom that allows trade-offs among peak-to-average power ratio (PAR), bit allocation capability, and frequency diversity. Instead of one large IDFT operation as in the OFDM transmitter, GCP time interleaves multiple smaller sized IDFT operations, so that PAR is correspondingly reduced. By appropriately selecting the block size in the BCM, the PAR value and the number of subcarriers for bit allocation can be chosen regardless of the length of the transmission block. When the block size in BCM is selected to be one or the entire size of the transmission block, the proposed GCP becomes OFDM or CPSC, respectively
8 citations
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