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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29 Aug 2005
TL;DR: A frequency channelized receiver that samples at an effective sampling frequency of 10 GS/s with 3b resolution is fabricated in a 0.25 /spl mu/m CMOS process and the functionality of the receiver is demonstrated by correctly reconstructing data from 10GS/s in a channel with significant ISI.
Abstract: A frequency channelized receiver that samples at an effective sampling frequency of 10 GS/s with 3b resolution is fabricated in a 0.25 /spl mu/m CMOS process. The chip occupies 4 mm/sup 2/ and consumes 1 W at 2.5 V supply. The functionality of the receiver is demonstrated by correctly reconstructing data from 10 GS/s in a channel with significant ISI.
13 citations
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...336 • 2005 IEEE International Solid-State Circuits Conference 0-7803-8904-2/05/$20.00 ©2005 IEEE....
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03 Apr 2011
TL;DR: In this article, the Single Carrier-Frequency Division Multiple Access (SC-FDMA) is introduced to PLC and compared with OFDMA for uplink smart meter transmission on power lines.
Abstract: Recently data communications over smart grid between the smart meters and the central modem attract a lot of interests. Extensive works have been done based on Orthogonal Frequency Division Multiple Access (OFDMA) system on one of the possible solutions for smart grid, i.e., low voltage power lines. Although OFDMA has been widely adopted in many wired and wireless communication systems, its multicarrier nature results in severely high peak-to-average power ratio (PAPR), which is undesirable for low-cost terminal equipments. On the other hand, Single Carrier-Frequency Division Multiple Access (SC-FDMA), a promising alternative to OFDMA, can greatly reduce PAPR while achieving similar performance and complexity. In this paper, SC-FDMA is for the first time introduced to PLC. We compare it with OFDMA, and study its potential for uplink smart meter transmission on power lines. Finally, simulation results also corroborate the advantages of SC-FDMA to OFDMA.
13 citations
Cites result from "Frequency domain equalization for s..."
...It turns out that SC-FDE is able to achieve the similar performance and essentially the same complexity as OFDM [3], [12]....
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25 Apr 2011
TL;DR: In this paper, an adaptive frequency-domain equalizer (FDE) for single carrier and OFDM indoor over Gbps data rate wireless receiver is proposed, which uses low computational complexity Least-Mean-Square (LMS) algorithm with Least Square (LS) channel estimation.
Abstract: This work proposes an adaptive frequency-domain equalizer (FDE) for single carrier and OFDM indoor over Gbps data rate wireless receiver. System simulation and specifications are based on the IEEE 802.15.3c standard. The proposed LS-LMS FDE uses low computational complexity Least-Mean-Square (LMS) algorithm with Least-Square (LS) channel estimation to accelerate the convergence speed. The FDE can be used for dual mode (SC and HSI) Wireless Personal Area Networks (WPAN) system. The simulation results show that the LS-LMS FDE can achieve 1.32∗10−4 BER in SC mode and 6.55∗10−3 in HSI mode (both uncoded) at SNR 14 dB. The total area is about 415K gate-count with 69% shared among single carrier and OFDM mode except 2 FFT. The power consumption is only 81.27 mW when working at 400MHz.
13 citations
TL;DR: It is proved analytically that there exists a rate loss in SC-FDMA compared to OFDMA if decoding is performed independently among the received data blocks for frequency selective channels and that such a loss can be mitigated by exploiting multiuser diversity and spatial diversity in multi-user systems with multiple receive antennas.
Abstract: This paper compares the information rate achieved by SC-FDMA (single-carrier frequency-division multiple access) and OFDMA (orthogonal frequency-division multiple access), where a linear frequency-domain equalizer is assumed to combat frequency selective channels in both systems. Both the single user case and the multiple user case are considered. We prove analytically that there exists a rate loss in SC-FDMA compared to OFDMA if decoding is performed independently among the received data blocks for frequency selective channels. We also provide a geometrical interpretation of the achievable information rate in SC-FDMA systems and point out explicitly the relation to the well-known waterfilling procedure in OFDMA systems. The geometrical interpretation gives an insight into the cause of the rate loss and its impact on the achievable rate performance. Furthermore, motivated by this interpretation we point out and show that such a loss can be mitigated by exploiting multiuser diversity and spatial diversity in multi-user systems with multiple receive antennas. In particular, the performance is evaluated in 3GPP-LTE uplink scenarios.
13 citations
08 Dec 2008
TL;DR: The analysis shows that the BER performance of the A-OFDM system bridges that of conventional OFDM and single carrier systems and certain advanced equalizers, such as MMSE equalizer, are found to significantly improve the BERN performance.
Abstract: To alleviate the high peak-to-average power ratio (PAPR) and sensitivity to carrier frequency offset (CFO) problems, an asymmetric OFDM (A-OFDM) system has been recently proposed. In this paper, the theoretical bit error rate (BER) analysis of the A-OFDM systems is presented. Various modulation methods, i.e., BPSK and M-ray QAM, and equalization techniques, i.e., zero forcing (ZF) and minimum mean square error (MMSE) criteria are considered. Our analysis shows that the BER performance of the A-OFDM system bridges that of conventional OFDM and single carrier systems. Certain advanced equalizers, such as MMSE equalizer, are found to significantly improve the BER performance of the A-OFDM systems. The analysis approach is generally applicable to most modulation schemes and can be extended to any preceded OFDM systems.
13 citations
Cites background or methods from "Frequency domain equalization for s..."
...4, it is obviously that MMSE equalizer significantly improves the performance of A-OFDM and SC-FDE systems....
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...In this paper, we show that the A-OFDM system bridges the OFDM and SC-FDE systems, evidenced by the theoretical BER performance analysis and numerical simulations....
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...Consider the two different placements of an IFFT operation in OFDM and SC-FDE [3]: in OFDM it is placed at the transmitter to multiplex the data into parallel subcarriers, while in SC-FDE it takes place at the receiver to convert FDE signals back into time domain symbols....
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...Both techniques have received much attention in the recent ”multi-carrier vs singlecarrier” debate [3]....
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...In this section, we present the simulation results of the BER performance of A-OFDM systems, together with that of OFDM and SC-FDE systems, for various modulations and equalizations....
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References
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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