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 Nov 2010
TL;DR: The single- user MMSEFDE is replaced by an MMSE spatial filtering (MMSE-SF) and an iterative joint multi-user MMSE- SF/SMUIC is proposed (called iterative co-operating MM SE-SF/ SMUIC) and the achievable bit error rate (BER) and throughput performances are evaluated by computer simulation.
Abstract: Frequency-domain filtered single carrier (SC)-FDMA signal has properties of reduced peak-to-average power ratio (PAPR) and increased frequency diversity gain. However, if the carrier-frequency separation is kept the same as in the case of the transmit filter roll-off factor α=0, the adjacent users' signal spectra overlap and the multi-user interference (MUI) is produced. In our previous work, we proposed an iterative joint single-user minimum mean square error frequency-domain equalization/successive MUI cancellation (called iterative joint MMSE-FDE/SMUIC), which performs iteratively a series of MMSE-FDE, spectrum combining, and SMUIC, for frequency-domain filtered SC-FDMA uplink. However, the residual ISI and MUI limit the BER performance improvement. In this paper, we replace the single-user MMSEFDE by an MMSE spatial filtering (MMSE-SF) and propose an iterative joint multi-user MMSE-SF/SMUIC (called iterative joint MMSE-SF/SMUIC). The achievable bit error rate (BER) and throughput performances are evaluated by computer simulation.
1 citations
Cites methods from "Frequency domain equalization for s..."
...The use of minimum mean square error frequency-domain equalization (MMSE-FDE) can exploit the channel frequency-selectivity to improve the bit error rate (BER) performance [3-5]....
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04 May 2014
TL;DR: This paper presents a nonlinear equalizer that combines frequency-domain (FD) pre-filtering with time-domain tree search detection and achieves a detection performance that is very close to that of the conventional tree search equalizer, but with a much lower complexity.
Abstract: Combating the intersymbol interference is an important issue in single-carrier block transmission systems. In this paper, we present a nonlinear equalizer that combines frequency-domain (FD) prefiltering with time-domain tree search detection. Simulation results show that the proposed algorithm achieves a detection performance that is very close to that of the conventional tree search equalizer (which employs the QRD-M algorithm), but with a much lower complexity. In addition, the proposed algorithm performs significantly better than the linear equalizers and decision-feedback equalizers, with only a modest increase in complexity.
1 citations
01 Aug 2006
TL;DR: The proposed MIMO SC-DS-CDMA transmission scheme is used in conjunction with hybrid automatic repeat request (HARQ) to provide better BER performance and throughput and employs both time domain and frequency domain spreading in contrast to other CDMA system.
Abstract: We propose a multiple input multiple output single carrier direct-sequence code division multiple access (MIMO SC-DS-CDMA) transmission scheme of high speed broadband communication over time varying frequency selective Rayleigh fading channels. The system is used in conjunction with Hybrid Automatic Repeat reQuest (HARQ) to provide better BER performance and throughput. Furthermore, the proposed scheme employs both Time domain and Frequency domain spreading in contrast to other CDMA system which employs only Time domain spreading. The frequency domain spreading provides frequency diversity that improves the performance of the system. BER performance of the scheme is studied and the results are presented.
1 citations
Cites background from "Frequency domain equalization for s..."
...Single carrier transmission with FDE can be designed to overcome the ISI problem arising from the severe frequency-selectivity of the channel and can achieve a BER performance similar to multicarrier transmission [13]....
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01 Jan 2015
TL;DR: In this article, the uplink transmission in BS cooperation schemes where mobile terminals (MTs) in adjacent cells share the same physical channel is considered, and the quantization requirements when sending the received signals, from different MTs, at different BSs to a central unit that performs the separation of different MRs using iterative frequency-domain receivers are investigated.
Abstract: The presented paper considers the uplink transmission in base station (BS) cooperation schemes where mobile terminals (MTs) in adjacent cells share the same physical channel. We consider single-carrier with frequency-domain equalization (SC-FDE) combined with iterative frequency-domain receivers based on the iterative block decision feedback equalization (IB-DFE). We study the quantization requirements when sending the received signals, from different MTs, at different BSs to a central unit that performs the separation of different MTs using iterative frequency-domain receivers. Our performance results show that a relatively coarse quantization, with only 4 bits in the in-phase and quadrature components of the complex envelope already allows close-to-optimum macro-diversity gains, as well as an efficient separation of the transmitted signals associated with each MT.
1 citations
10 Apr 2006
TL;DR: Computer simulation results show that the proposed scheme outperforms the typical SC-FDE using full samples over relatively severe frequency selective fading channels when applying 1-bit/sample transmission.
Abstract: This paper presents the periodic spectrum transmission for single-carrier frequency-domain equalization (SC-FDE) employing space-time transmit diversity (STTD). The proposed scheme utilizes only even-numbered samples within a time domain data block to createa periodical spectrum which provides frequency redundancy. Frequency redundancy is used for sub-channel combining before FDE, which alleviates the loss of orthogonality caused by FDE under frequency selective fading channels. Therefore, the proposed scheme has an advantage of enhancing the overall frequency diversity benefit while keeping the space diversity benefit achieved by STTD. Computer simulation results show that the proposed scheme outperforms the typical SC-FDE using full samples over relatively severe frequency selective fading channels when applying 1-bit/sample transmission.
1 citations
Cites methods from "Frequency domain equalization for s..."
...After MRC combining, each sub-channel signal is multiplied by an appropriate weighting factor W (k) to reduce the inter-bit interference because the frequency selective fading introduces the loss of orthogonality among the different data samples which spread over N ′ sub-channels [3]....
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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