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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 Dec 2016
TL;DR: A block-wise single carrier (BWSC) waveform with low peak-to-average ratio (PAPR) is proposed to lower the cost of massive number of RF components needed to realize an m-MIMO structure for mmwave.
Abstract: Ultra broadband mobile communication is a key requirement of fifth generation (5G) wireless cellular networks. To fulfill this requirement much larger bandwidth is needed which can be delivered in millimeter band from 30 to 300 GHz. Beam formed transmission over a massive MIMO (m-MIMO) structure is an essential element of a millimeter wave (mmwave) system to compensate the large air propagation loss. This however requires new air interface design to overcome hardware limitations tied to m-MIMO and mmwave, particularly for higher frequencies above 40 GHz. In this paper a block-wise single carrier (BWSC) waveform with low peak-to-average ratio (PAPR) is proposed to lower the cost of massive number of RF components needed to realize an m-MIMO structure for mmwave. Same as OFDM, data-based cyclic prefix (CP) is attached to every BWSC block to enable frequency domain equalization (FDE). Evaluations have been conducted to demonstrate the advantage of data-CP BWSC over orthogonal division multiplexing (OFDM) and null-CP single carrier waveform in terms of some key performance measures such as system efficiency, adjacent channel leakage ratio (ACLR), inter-symbol inference (ISI) and PAPR.

11 citations

Proceedings ArticleDOI
Xiliang Luo1, Peter Gaal1, Wanshi Chen1, Zhang Xiaoxia1, Juan Montojo1 
30 Nov 2009
TL;DR: A novel transmission scheme is proposed: "One Symbol STBC" that operates on a single SC-FDM symbol and can achieve full transmit diversity while maintaining single-carrier waveform's low PAPR.
Abstract: In 3GPP LTE-Advanced, open-loop transmit diversity schemes for the uplink are of great interest. It seems that, space-frequency block code (SFBC), the diversity scheme already adopted in the downlink of LTE Release-8, would be a natural option. However, when applying SFBC directly to the uplink, the resulting waveform at one transmit antenna becomes multi-carrier like with higher peak to average power ratio (PAPR), which limits the power efficiency of the corresponding power amplifier (PA). Another option will be to apply conventional space-time block code (STBC) scheme over two consecutive single-carrier frequency-division multiplexing (SC-FDM) symbols. But in some cases, one uplink slot contains an odd number of data SC-FDM symbols, then the last data symbol in the slot will become an orphan symbol over which the conventional STBC will not work. Hence, we want to find a transmission scheme that operates on a single SC-FDM symbol and is able to achieve similar diversity performance as SFBC. Meanwhile, we would like to preserve single-carrier waveform at both transmit antennas to maximize the PA efficiency. To meet this end, we propose a novel transmission scheme: "One Symbol STBC" that operates on a single SC-FDM symbol and can achieve full transmit diversity. Meanwhile, the single-carrier waveform requirement is fulfilled at both transmit antennas. In addition to theoretical justifications, link-level simulations are also carried out which proves our proposed "One Symbol STBC" indeed achieves similar diversity performance as SFBC while maintaining single-carrier waveform's low PAPR.

11 citations


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

  • ...(17): 0(0): 0% overhead, 5(1): 10% overhead, 10(2): 20% overhead; Symbol detector: first carrying out MMSE equalization in frequency domain [8], [12], then performing symbol detection in time domain; Turbo decoder: max-Log-MAP algorithm with maximum 8 iterations; Slot boundary frequency hopping: no; Pilot sequences for different tx antennas: different cyclic shifts of a common Zadoff-Chu sequence [2]; Channel estimation: averaging two pilots within one subframe of length 1ms....

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Journal ArticleDOI
TL;DR: This article proposes a new transceiver design for Single carrier frequency division multiple access (SCFDMA) system based on discrete wavelet transform (DWT) and suggests the application of Walsh Hadamard transform for linear precoding (LP) to improve the PAPR performance of the system.
Abstract: This article proposes a new transceiver design for Single carrier frequency division multiple access (SCFDMA) system based on discrete wavelet transform (DWT). SCFDMA offers almost same structure as Orthogonal frequency division multiple access (OFDMA) with extra advantage of low Peak to Average Power Ratio (PAPR). Moreover, this article also suggests the application of Walsh Hadamard transform (WHT) for linear precoding (LP) to improve the PAPR performance of the system. Supremacy of the proposed transceiver over conventional Fast Fourier transform (FFT) based SCFDMA is shown through simulated results in terms of PAPR, spectral efficiency (SE) and bit error rate (BER).

11 citations


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

  • ...Though, OFDMA is an attractive technology to circumvent inter-symbol interference (ISI) however these systems are also very sensitive to high PAPR and carrier frequency offsets (CFO) [4, 5]....

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  • ...Implementation of OFDMA with DWT not only includes the advantages of FFT-OFDM but also provides additional benefits in the form of low PAPR, high spectral efficiency due to non-utilization of CP and strong resistance to CFO [10]....

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  • ...OFDMA is an attractive technology to circumvent inter-symbol interference (ISI) however these systems are also very sensitive to high PAPR and carrier frequency offsets (CFO) [4, 5]....

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  • ...Therefore, OFDM system does not provide better spectral shaping to its sub-carriers due to its poor frequency localization and thus, makes it vulnerable to CFO [7]....

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Journal ArticleDOI
TL;DR: This paper proposes a Raised Cosine-like companding scheme to reduce the peak-to-average power ratio (PAPR) of SCFDMA signals and shows that this scheme can offer better PAPR reduction by properly choosing the parameters.
Abstract: The 3rd generation partnership project long term evolution standard uses orthogonal frequency division multiplexing access in downlink and single carrier frequency division multiple access (SCFDMA) scheme for the uplink transmissions, which utilizes single carrier modulation and frequency domain equalization. In this paper, we proposed a Raised Cosine-like companding scheme to reduce the peak-to-average power ratio (PAPR) of SCFDMA signals. The proposed scheme can transform the original SCFDMA signals into Raised Cosine-like-distributed. Moreover, this scheme can compress the large signals, while maintaining the average power constant. Computer simulation results show that the proposed companding scheme can offer better PAPR reduction by properly choosing the parameters.

11 citations


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

  • ...One prominent advantage over OFDMA is that the SCFDMA signal has lower PAPR because of its inherent single carrier structure([3])....

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Proceedings ArticleDOI
06 Jul 2014
TL;DR: It will be shown that PAM-FDE performs best for this kind of channel, and neither bit loading enhanced DMT nor single subcarrier block transmission with FDE can offer a higher data rate at a given average optical power.
Abstract: OFDM and its real valued version discrete multitone transmission (DMT) are popular schemes to compensate dispersion in direct detection optical systems. They employ an inverse fast Fourier transform (IFFT) at the transmitter and a fast Fourier transform (FFT) at the receiver, whereas the data symbols are processed block-wise. Block transmission combined with frequency domain equalization (FDE) has been recognized as a possible alternative to the DMT schemes, where the IFFT is moved from the transmitter to the receiver. This paper compares various bit loading enhanced DMT schemes such as asymmetrically clipped DMT and DC-biased DMT to PAM block transmission with FDE and to various single subcarrier FDE schemes. Moreover, a new approach termed asymmetrically clipped orthogonal PAM, is proposed in this work. Simulation results are presented for theoretical channels with a Gaussian low-pass profile. It will be shown that PAM-FDE performs best for this kind of channel, and neither bit loading enhanced DMT nor single subcarrier block transmission with FDE can offer a higher data rate at a given average optical power.

11 citations


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

  • ...However, due to the problems associated with OFDM such as a high peak-to-average power ratio, the concept of single carrier transmission with FDE [1] has been recognized as a powerful alternative in RF communications....

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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