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Journal ArticleDOI

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.

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Citations
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Proceedings ArticleDOI
01 Oct 2014
TL;DR: PAPR and BER performances when using the proposed TD-SLM are evaluated by computer simulation and are compared to conventional joint Tx/Rx SC-FDE and joint TX/RX SC-fDE with FD-SLm.
Abstract: Transmit filtering, transmit equalization, precoding, or power allocation increases the peak-to-average power ratio (PAPR) of transmit single-carrier (SC) signal due to change in frequency-domain spectrum. Recently, we proposed a frequency-domain based selected mapping (FD-SLM) for suppressing the increased PAPR introduced by the transmit frequency-domain equalization (Tx-FDE). However, FD-SLM provides minor contribution when computational complexity is considered. In this paper, we are motivated by the fact that a “bad” arrangement of modulated symbols in a transmission block leads to high peak power, and propose a time-domain phase rotation called time-domain SLM (TD-SLM). PAPR and BER performances when using the proposed TD-SLM are evaluated by computer simulation and are compared to conventional joint Tx/Rx SC-FDE and joint Tx/Rx SC-FDE with FD-SLM.

6 citations


Cites background or methods from "Frequency domain equalization for s..."

  • ..., in LTE-Advanced (LTE-A) system, because of lower PAPR, while the use of frequency-domain equalization (FDE) can take advantage of channel frequency selectivity to improve the BER performance [4]....

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  • ...By using the minimum mean-square error (MMSE) criterion [4, 6] where the mean-square error (MSE) is calculated between frequency-domain transmitted and received signal....

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Proceedings ArticleDOI
01 Dec 2011
TL;DR: This paper investigates the diversity order of a SC-CP-FDE system without channel coding in frequency-selective channels and shows that with MMSE-FD-DFE, the asymptotic achievable diversity order is Lc +1 when the block length N is sufficiently large, i.e., full multipath diversity is asymPTotically achieved.
Abstract: Single carrier cyclic prefix system with frequency domain equalization (SC-CP-FDE) is an attractive technology for broadband wireless communications. In this paper, we investigate the diversity order of a SC-CP-FDE system without channel coding in frequency-selective channels. Existing analytic proofs in [6], [7] indicate that the achievable diversity order is only 1, which contradicts the conclusion in [11] and simulation results in [1]-[3]. We explain why the proofs in [6], [7] can not support the claim that SC-CP system is unable to provide any frequency diversity gain. We then re-investigate the diversity order of a SC-CP system with frequency domain decision feedback equalizer (FD-DFE) based on MMSE criteria at the receiver end. Adopting outage analysis instead of pairwise error probability (PEP) analysis, we show that with MMSE-FD-DFE, the asymptotic achievable diversity order is Lc +1 when the block length N is sufficiently large, where Lc +1 is the number of independent channel paths, i.e., full multipath diversity is asymptotically achieved.

6 citations


Cites background or methods from "Frequency domain equalization for s..."

  • ...Specially, we use the frequency domain decision feedback equalizer (FD-DFE) at the receiver end, which was introduced in [2]-[4]1....

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  • ...1Because FD-DFE has a frequency domain feedforward equalizer and a time domain feedback equalizer, it is also called hybrid time-frequency domain decision feedback equalizer in [2], [3]....

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Proceedings ArticleDOI
01 Oct 2011
TL;DR: The bit error rate (BER) performance is evaluated by computer simulation, and it is shown that overlap FDE using the newly derived MMSE weight reduces the residual inter-symbol interference (ISI) more and hence, improves the BER performance.
Abstract: Overlap frequency-domain equalization (FDE) requires no cyclic prefix (CP) insertion. In this paper, a new minimum mean square error (MMSE) weight is derived for the overlap FDE. In the previous paper, the MMSE weight for overlap FDE is derived by approximating the IBI as a white Gaussian variable. However, the IBI is an independent colored noise. We derive a new MMSE weight by taking into account this fact. We evaluate the bit error rate (BER) performance by computer simulation, and show that overlap FDE using the newly derived MMSE weight reduces the residual inter-symbol interference (ISI) more and hence, improves the BER performance.

6 citations


Cites background from "Frequency domain equalization for s..."

  • ...The frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can achieve a good bit error rate (BER) performance by exploiting the channel frequency-selectivity [3]-[5]....

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Journal ArticleDOI
TL;DR: In this article, a comprehensive performance comparison of MC- and DS-CDMA using frequency domain equalization (FDE) is presented, and the performance can be further improved by using multi-input/multi-output (MIMO) antenna technique.
Abstract: Frequency-domain equalization (FDE) technique may play an important role for broadband packet transmission using MC- and DS-CDMA. The downlink performance is significantly improved with FDE; however, the uplink performance is limited by the multi-access interference (MAI). To remove the MAI while gaining the frequency diversity effect through the use of FDE, frequency-domain block spread CDMA can be used. The performance can be further improved by the use of multi-input/multi-output (MIMO) antenna technique. Recently, particular attention has been paid to MIMO space division multiplexing (SDM) to significantly increase the throughput without expanding the signal bandwidth. In this paper, we present a comprehensive performance comparison of MC- and DS-CDMA using FDE.

6 citations

Proceedings ArticleDOI
01 Aug 2015
TL;DR: It was found out that when compared to their strictly linear versions their error performance is more robust with respect to these errors, and even when this error is considered their performance is slightly better.
Abstract: In this paper the effect of channel estimation errors in single carrier systems using frequency domain widely linear iterative equalization is investigated. It was found out that when compared to their strictly linear versions their error performance is more robust with respect to these errors. They do not have the high error floor present in the error performance of strictly linear systems that do not take into account the channel estimation error into account; even when this error is considered their performance is slightly better.

6 citations


Cites methods from "Frequency domain equalization for s..."

  • ...In this paper we have investigated the error performance of widely linear iterative SC-FDE systems under imperfect channel estimation....

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  • ...The remainder of the paper is organized as follows: the system model of the SC-FDE system using a widely linear frequency domain iterative equalizer that takes into account the channel estimation error in this process is presented in Section II....

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  • ...The effect of channel estimation errors in SC-FDE systems using linear and iterative equalization was dealt with in [11]....

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  • ...978-1-4673-6540-6/15/$31.00 c©2015 IEEE Index Terms—SC-FDE systems, widely linear processing, iterative equalization, channel estimation errors....

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  • ...This is the case for the uplink implementation in the 3GPP long term evolution (LTE) standard, where a variant of SC-FDE is implemented....

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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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Journal ArticleDOI
Jr. L.J. Cimini1
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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Book
Simon Haykin1
01 Mar 1991

2,447 citations

Journal ArticleDOI
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

Journal ArticleDOI
D. Chu1
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