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
More filters
05 Jun 2011
TL;DR: An iterative minimum mean square error signal detection and interference cancellation (MMSED-IC) for turbo coded uplink SC-FDMA MIMO using HARQ is proposed, and it is shown that by using the proposed scheme, SC-fdMA with alpha=1 can achieve higher throughput performance than not only SC- FDMA withalpha=0 but also OFDMA using IAI cancellation.
Abstract: For high-speed packet access, hybrid automatic repeat request (HARQ) and multiple-input multiple-output (MIMO) multiplexing are indispensable techniques As the multiple-access technique, single carrier (SC)-frequency-division multiple-access (FDMA) using transmit filtering is promising The use of square-root Nyquist transmit filter reduces peak-to-average power ratio (PAPR) of the transmit SC-FDMA signal and increases the frequency diversity gain However, if the carrier-frequency separation among multiple-access users is kept the same as in the case of the transmit filter's roll-off factor alpha=0 (ie, brick wall filter), the adjacent users' signal spectra overlap and the multi-user interference (MUI) is produced In this paper, we propose an iterative minimum mean square error signal detection and interference cancellation (MMSED-IC) for turbo coded uplink SC-FDMA MIMO using HARQ In the proposed MMSED-IC, not only the inter-antenna interference (IAI) and residual inter-symbol interference (ISI) but also MUI are cancelled in an iterative fashion We evaluate the HARQ throughput performances by computer simulation, and show that by using the proposed scheme, SC-FDMA with alpha=1 can achieve higher throughput performance than not only SC-FDMA with alpha=0 but also OFDMA using IAI cancellation
19 citations
Cites methods from "Frequency domain equalization for s..."
...For broadband wireless single-carrier (SC) transmission, the use of minimum mean square error frequency-domain equalization (MMSE-FDE) can exploit the channel frequency-selectivity [1],[2] to improve the bit error rate (BER) performance [3-5]....
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TL;DR: Simulation results show that the proposed scheme outperforms the interleave- division multiple-access (IDMA) scheme in the block error rate even for severely frequency-selective channel, while providing considerably lower computational complexity.
Abstract: In this letter, we propose a new multiuser detection scheme for single-carrier modulation with frequency-domain equalization (SC-FDE). We first present mathematical formulations of multiuser detection for the SC-FDE system with user- specific interleaving. The proposed structure employs spreader and different interleaver for each user at the transmitter, and re moves multiuser interference with an iterative detection method in the frequency domain at the receiver. Simulation results show that the proposed scheme outperforms the interleave- division multiple-access (IDMA) scheme in the block error rate even for severely frequency-selective channel, while providing considerably lower computational complexity.
19 citations
Patent•
03 Mar 2016
TL;DR: In this paper, a backhaul radio that operates in multipath propagation environments such as obstructed LOS conditions with uncoordinated interference sources in the same operating band is disclosed.
Abstract: A backhaul radio is disclosed that operates in multipath propagation environments such as obstructed LOS conditions with uncoordinated interference sources in the same operating band. Such a backhaul radio may use a combination of interference mitigation procedures across multiple of the frequency, time, spatial and cancellation domains. Such backhaul radios may communicate with each other to coordinate radio resource allocations such that accurate interference assessment and channel propagation characteristics assessment may be determined during normal operation.
19 citations
Proceedings Article•
01 Aug 2011TL;DR: This paper proposes a novel 2-stage receiver for single user single-carrier frequency-division multiple access (SC-FDMA) uplink transmission where the IAI between the MIMO streams needs to be addressed.
Abstract: This paper proposes a novel 2-stage receiver for single user single-carrier frequency-division multiple access (SC-FDMA) uplink transmission. The proposed receiver consists of separate stages for inter-symbol interference (ISI) and inter-antenna interference (IAI) mitigation in frequency selective MIMO channels. The main focus is on the single user case where the IAI between the MIMO streams needs to be addressed. A new 2-stage receiver structure is introduced where sphere detection algorithms are used in the time domain to remove the IAI while minimum mean square error (MMSE) equalization is used in the frequency domain to suppress the ISI. The numerical results show that the proposed receiver outperforms the conventional MMSE receiver under the presence of spatial correlation between both the transmit and receive antennas.
18 citations
Cites background or methods from "Frequency domain equalization for s..."
...SC-FDMA has been selected in the uplink instead of orthogonal frequency division multiplexing (OFDM) because of its reduced peak-to-average power ratio which lowers the transmitter cost in the form of cheaper power amplifier [2]....
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...MMSE 8−best 16−best SSFE [4,3,2,2] SSFE [8,8,1,1] Turbo receiver, 2 iter....
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...MMSE 8−best 16−best SSFE[4,3,2,2] 8−best, 2 iter....
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...The node spanning vectors correspond to those used in the simulations and are [8,8,1,1,1,1,1,1] for SSFE-1 and [4,3,2,2,1,1,1,1] for SSFE2....
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...MMSE 8−best 16−best SSFE [4,3,2,2] 8−best, 2 iter....
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17 May 2004
TL;DR: The use of multiple antennas at the BS (base station) allows significant improvements on the spectral efficiency of wireless communication systems by increasing the number of simultaneous users in a given cell, and the use of single-carrier modulation combined with frequency-domain equalization techniques, which are known to be excellent candidates for severe time-dispersive channels.
Abstract: The use of multiple antennas at the BS (base station) allows significant improvements on the spectral efficiency of wireless communication systems by increasing the number of simultaneous users in a given cell. We introduce a new iterative multiuser detection scheme for systems requiring high-rate transmission in severe time-dispersive channels. We consider the use of single-carrier modulation combined with frequency-domain equalization techniques, which are known to be excellent candidates for severe time-dispersive channels. The BS employs multiple antennas and consists of an iterative LST (layered space-time) receiver combined with frequency-domain equalization techniques. Our performance results show that the proposed receiver structure has excellent performance, which can be very close to the matched filter bound, even for severe time-dispersive channels and in the presence of strongly interfering channels.
18 citations
Cites background from "Frequency domain equalization for s..."
...Recently, a new SC system with decision feedback equalization has been proposed for Single-Input Single-Output (SISO) channels [4, 5]....
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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