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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
More filters
Proceedings ArticleDOI
11 May 2008
TL;DR: It is shown that a significant SNR degradation is observed at the victim UE with smaller resource block size, when evaluated in a realistic channel, and the SNR loss at 10% BLER target is less than 1 dB.
Abstract: In this paper we investigate the impact of in-band interference on the uplink multiple access of UMTS Terrestrial Radio Access, long term evolution (UTRA LTE). In- band and out-of-band interference arise as a result of transmitter imperfections. Out-of- band, or adjacent channel, interference can be controlled by a spectral shaping filter. However, the shaping filter cannot control the leakage within the system bandwidth, and the resulting leakage can interfere with other users' transmission in the uplink multiple access. The situation is emphasized when the resource block allocation size is small, and when the interfering signal is received at higher power spectral density (PSD). The effect of frequency offset and different PSD level from the UE interferers to a victim UE is studied. The impact on different UE resource block size allocation is also investigated. The results are obtained from an LTE uplink link level simulation. It is shown that a significant SNR degradation is observed at the victim UE with smaller resource block size, when evaluated in a realistic channel. Considering that the frequency offset can be maintained below 200 Hz and PSD level offset below 10 dB, the SNR loss at 10% BLER target is less than 1 dB.

246 citations


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

  • ...A complex receiver for high data rate system can thus be avoided by using frequency domain equalizer [6]....

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Journal ArticleDOI
TL;DR: A survey on IM is presented to provide the readers with a better understanding of its principles, advantages, and potential applications and a range of challenges and open issues on IM are discussed.
Abstract: In fifth generation wireless networks, the escalating teletraffic and energy consumption has necessitated the development of green communication techniques in order to further enhance both the system’s spectral efficiency and energy efficiency In the past few years, the novel index modulation (IM) has emerged as a promising technology that is widely employed in wireless communications In this paper, we present a survey on IM in order to provide the readers with a better understanding of its principles, advantages, and potential applications We start with a comprehensive literature review, where the concept of IM is introduced, and various existing IM schemes are classified according to their signal domains, including the frequency domain, spatial domain, time domain and channel domain Then the principles of different IM-aided systems are detailed, where the transceiver design is illustrated, followed by descriptions of typical systems and corresponding performance evaluation A range of challenges and open issues on IM are discussed before we conclude this survey

243 citations


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

  • ...determined by the two index bits, with the bit streams [0,0], [0,1], [1,0] and [1,1] corresponding to the index patterns [1,2], [2,3], [3,4] and [1,4], respectively....

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  • ...In this section, we briefly introduce the basic communication system models adopted by various IM techniques, including MIMO and single-input multiple-output (SIMO) as well as OFDM and SC-FDE....

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  • ...I. INTRODUCTION DUE TO the fast evolution of smart communication termi-nals and in order to meet the explosive increase of mobile traffic, high-rate transmission schemes have attracted increasing attention from both the academia and industry, featured by orthogonal frequency division multiplexing (OFDM) [1] and single-carrier frequency-domain equalization (SC-FDE) [2]....

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  • ...This makes SC-FDE attractive for uplink transmission....

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  • ...For this aforementioned merit, SC-FDE has also been introduced to VLC [11], where the nonlinearities of LED are severe, and it outperforms other conventional optical modulation schemes, in terms of SNR gains....

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Journal ArticleDOI
TL;DR: From performance simulations on a wireless dispersive fading channel, it is observed that the IBDFE outperforms existing DFEs and exhibits a reduction of the computational complexity when compared against existing schemes, both in signal processing and in filter design.
Abstract: Error-propagation phenomena and computational complexity of the filters' design are important drawbacks of existing decision-feedback equalizers (DFE) for dispersive channels. In this paper, we propose a new iterative block DFE (IBDFE) which operates iteratively on blocks of the received signal. Indeed, a suitable data-transmission format must be used to allow an efficient implementation of the equalizer in the frequency domain, by means of the discrete Fourier transform. Two design methods are considered. In the first method, hard detected data are used as input of the feedback, and filters are designed according to the correlation between detected and transmitted data. In the second method, the feedback signal is directly designed from soft detection of the equalized signal at the previous iteration. Estimators of the parameters involved in the IBDFE design are also derived. From performance simulations on a wireless dispersive fading channel, we observed that the IBDFE outperforms existing DFEs. Moreover, the IBDFE exhibits a reduction of the computational complexity when compared against existing schemes, both in signal processing and in filter design.

240 citations


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

  • ...In the case of a PN-extended transmission, a technique for the channel estimate has been presented in [9]....

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  • ...For a comparison with the results of [8] and [9], we assumed that in all the considered schemes, the receive filter is matched to the transmit pulse shape, and the equalizer sampling is at the symbol rate....

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  • ...Recently, a considerable reduction of complexity has been achieved by the FD linear equalizer [7] and by the DFE with a hybrid structure (H-DFE) [8], [9], where the feedforward (FF) filter is realized in the FD, while the FB filter is realized in the TD....

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  • ...On the other hand, for channels with a low or moderate dispersion, very simple FB filters can be used [9], and the complexity reduction provided by the IBDFEs may be negligible....

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Journal ArticleDOI
TL;DR: In this article, a 2×2 multiple-input-multiple-output (MIMO) OFDM representation for the single-mode fiber optical channel is presented and discussed.
Abstract: There has been growing interest in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) We aim to present the case that the time for CO-OFDM has come, in terms of the demand from today's ever-advancing optical networks and the availability of its underlying technologies We first lay out the signal processing aspect for CO-OFDM and then show a 2×2 multiple-input-multiple-output (MIMO) OFDM representation for the single-mode fiber optical channel Through numerical simulation and experimental demonstration, we further present and discuss various MIMO-OFDM systems focusing on their polarization-mode dispersion resilience Among those systems, the 2×1 MIMO-OFDM configuration incorporating polarization-time coding shows promise for optical access networks and broadcast networks Finally, another class of the frequency-domain equalization techniques, namely, incoherent or coherent optical single-carrier frequency-domain equalization (CO-SCFDE) is discussed and experimentally demonstrated

226 citations


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

  • ...There are many methods of performing channel estimation and the basic idea is to transmit a known sequence as preamble [49], and in this work we use the Chu sequence that has a flat magnitude in both the time and frequency domains [47,49]....

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  • ...Although OFDM has gained popularity in the past decade and has been widely implemented in numerous communication standards, there has been on-going debate about which is superior, OFDM and SCFDE [47,48]....

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  • ...32 It can be seen that both OFDM and SCFDE are much superior to SCTDE in their scalability with both dispersion and bit rate....

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Book
31 Jan 2019
TL;DR: Understand the fundamentals of wireless and MIMO communication with this accessible and comprehensive text, which provides a sound treatment of the key concepts underpinning contemporary wireless communication and M IMO, all the way to massive MIMo.
Abstract: Understand the fundamentals of wireless and MIMO communication with this accessible and comprehensive text. Viewing the subject through an information theory lens, but also drawing on other perspectives, it provides a sound treatment of the key concepts underpinning contemporary wireless communication and MIMO, all the way to massive MIMO. Authoritative and insightful, it includes over 330 worked examples and 450 homework problems, with solutions and MATLAB code and data available online. Altogether, this is an excellent resource for instructors and graduate students, as well as an outstanding reference for researchers and practicing engineers.

206 citations

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