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
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17 Dec 2010
TL;DR: Suboptimal precoding vector (PV) selection schemes combined with frequency domain scheduling when closed-loop MIMO precoding is adopted in the LTE (Long-Term Evolution)-Advanced uplink based on single carrier-frequency division multiple access (SC-FDMA) radio access are proposed.
Abstract: This paper proposes suboptimal precoding vector (PV) selection schemes combined with frequency domain scheduling when closed-loop MIMO precoding is adopted in the LTE (Long-Term Evolution)-Advanced uplink based on single carrier-frequency division multiple access (SC-FDMA) radio access. In the proposed schemes, frequency domain channel-dependent scheduling is performed based on a tentatively selected PV for each subband, and then a suitable PV is selected that is common to the contiguously allocated resource blocks in the frequency domain for each UE in order to achieve the single carrier property, i.e., a low peak-to-average power ratio (PAPR). System-level simulation results show that by employing the proposed scheme, the sector throughput performance is increased by 1.6% and 2.3% compared to the conventional scheme in the case of 2-by-2 and 4-by-2 MIMO, respectively. Furthermore, we clarify that the losses in the achievable sector throughput by using the proposed scheme are only 0.9% and 2.4% for 2-by-2 and 4-by-2 MIMO, respectively, compared to the ideal condition using frequency selective precoding.
4 citations
Cites methods from "Frequency domain equalization for s..."
...A frequency domain equalizer based on the minimum mean squared error (MMSE) is used [14]....
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Proceedings Article•
14 May 2012TL;DR: An efficient transceiver scheme for SC-FDMA using the wavelet transform using the Integer Wavelet Transform and its Inverse and results show that the proposed scheme provides better performance, when compared to the conventional SC- FDMA, while the complexity of the system is slightly increased.
Abstract: Recent research has shown that the Single Carrier Frequency Division Multiple Access (SC-FDMA) system is an attractive technology for uplink broadband wireless communications, because it does not have the problems of Orthogonal Frequency Division Multiple Access (OFDMA) systems such as the large Power-to-Average Power Ratio (PAPR). In this paper, an efficient transceiver scheme for SC-FDMA using the wavelet transform is proposed. In this scheme, the Fast Fourier Transform (FFT) and its Inverse (IFFT) are replaced by the Integer Wavelet Transform (IWT) and its Inverse (HWT). Wavelet filter banks at the transmitter and the receiver demonstrate the ability to reduce distortion in the reconstructed signal, while retaining all the significant features present in the signal. The performance of the proposed scheme is investigated with different wireless channels. Simulation results show that the proposed scheme provides better performance, when compared to the conventional SC-FDMA, while the complexity of the system is slightly increased.
4 citations
Cites background from "Frequency domain equalization for s..."
...This is achieved by making all the sub-carriers orthogonal to each other [1] [2], but it has several inherent disadvantages such as the large PAPR and the sensitivity to carrier frequency offsets [3] [4] [5]....
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01 Mar 2007
TL;DR: The authors show the signal separation performance applying the SIC and PIC techniques with the timing control scheme in LOS environments by bit error rate (BER) evaluation.
Abstract: The UWB-IR (ultra wideband-impulse radio) technology and MIMO system have attracted interest for next generation high rate radio communications. The authors researched IMO-UWB systems using the FDE (frequency domain equalization) technique with the MMSE spatial filtering technique. The UWB system will be used in short range wireless transmissions. Then, we usually have line-of-sight (LOS) environments in the MIMO-UWB systems. The authors conducted propagation measurement and evaluated the transmission performance of MIMO-UWB systems in LOS environments. Then, the authors proposed a timing control scheme for performance improvement. SIC (successive interference canceller) and PIC (parallel interference canceller) are known as better signal separation techniques in MIMO systems. In these techniques, the authors obtain diversity gain subtracting the data detected by a spatial filtering technique from the received signal. Therefore, we can achieve better signal separation performance by the diversity gain. The authors found that the timing control scheme is also needed for the SIC and PIC techniques in LOS MIMO-UWB environments by bit error rate (BER) evaluation. In this paper, the authors show the signal separation performance applying the SIC and PIC techniques with the timing control scheme in LOS environments.
4 citations
Cites background from "Frequency domain equalization for s..."
...The multiple-input multiple-output ultra wideband (MIMO-UWB) systems for higher rate radio communications have been researched in [2],[3]....
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01 Sep 2009
TL;DR: Results show that the newly pro- posed FBR calculation methods for uncoded and coded M-ary quadrature amplitude modulation (QAM) systems has similar or better error rate performance than the TS method without the associated loss of bandwidth efficiency.
Abstract: A new class of iterative block decision feedback equalizer (IB-DFE) was pioneered by Chan and Benvenuto. Unlike the conventional DFE, the IB-DFE is optimized according to the reliability of the feedback (FB) symbols. Since the use of the training sequence (TS) for feedback reliability (FBR) estimation lowers the bandwidth efficiency, FBR estimation without the need for additional TS is of considerable interest. However, prior FBR estimation is limited in the literature to uncoded M-ary phase- shift keying (PSK). In this paper we investigate FBR calculation methods for uncoded and coded M-ary quadrature amplitude modulation (QAM) systems. Results show that our newly pro- posed method has similar or better error rate performance than the TS method without the associated loss of bandwidth efficiency.
4 citations
Cites background from "Frequency domain equalization for s..."
...Hence one SC-FDE block period is TBLK = (512+64) 15kHz×512 = 75µs....
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...Hybrid decision feedback equalizers (H-DFE) that consist of a FD feedforward (FF) filter and a time-domain (TD) feedback (FB) filter were proposed in [1] and [4] for SC-FDE....
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...1 shows a SC-FDE receiver with an IB-DFE, where the FF and FB filters are both implemented in the FD....
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...I NTRODUCTION Broadband single-carrier (SC) systems such as single-carrier frequency-domain equalization (SC-FDE) [1] and singlecarrier frequency division multiple access (SC-FDMA) [2] have attracted significant research interest in recent years....
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...Broadband single-carrier (SC) systems such as single-carrier frequency-domain equalization (SC-FDE) [1] and singlecarrier frequency division multiple access (SC-FDMA) [2] have attracted significant research interest in recent years....
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06 May 2012
TL;DR: Experimental results show that when 2-by-2 Rank-2 SU-MIMO, i.e., spatial multiplexing, is applied, a cross-polarized antenna configuration exhibits better throughput performance compared to that using co- polarized antennas and the location probability for achieving throughput greater than 200 Mbps is clearly increased.
Abstract: This paper presents experimental results to clarify the throughput performance and effective location probability for closed-loop single-user (SU)-MIMO transmission considering the effect of antenna configurations in the LTE-Advanced uplink. The achievable throughput performance with adaptive modulation and coding (AMC) and hybrid automatic repeat request (HARQ) is evaluated using the implemented LTE-Advanced transceivers, where the total transmission power and bandwidth per component carrier of a mobile station (MS) are set to 23 dBm and 17.28 MHz, respectively. The experimental results show that when 2-by-2 Rank-2 SU-MIMO, i.e., spatial multiplexing, is applied, a cross-polarized antenna configuration exhibits better throughput performance compared to that using co-polarized antennas and the location probability for achieving throughput greater than 200 Mbps is clearly increased. Furthermore, we confirm that the throughput performance using cross-polarized antennas is very robust against the variation in MS antenna angles irrespective of the rank values for SU-MIMO transmission. The experimental results also show that 2-by-2 Rank-2 SU-MIMO using the cross- polarized antennas improves the throughput performance compared to 1-by-2 SIMO at the location probability of greater than 60% even when the MS antenna gain imbalance level of 12 dB is considered.
4 citations
Cites methods from "Frequency domain equalization for s..."
...To the best knowledge of the authors, such field experiments for MIMO transmission techniques with LTE SC-FDMA radio access based on discrete Fourier transform (DFT)-spread OFDM [10] had not been reported....
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...LTE provides full IP packet-based radio access with low latency and adopts an intra-cell orthogonal multiple access scheme such as orthogonal frequency division multiple access (OFDMA) and single-carrier frequency division multiple access (SC-FDMA) in the downlink and uplink, respectively....
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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