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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01 Dec 2012
TL;DR: This paper considers the use of SC-FDE schemes in the uplink of BS cooperation architectures where the receiver is based on the IB-DFE (Iterative Block Decision Feedback Feedback Equalization) concept and presents a simple and accurate analytical model for obtaining the corresponding BER performance.
Abstract: BS (Base Station) cooperation architectures provide significant capacity gains, since they allow users in adjacent cells to share the same physical channel. By employing iterative frequency-domain receivers that combine signals received by different BSs we can effectively separate the signals associated to different MTs. In this paper we consider the use of SC-FDE (Single-Carrier with Frequency-Domain Equalization) schemes in the uplink of BS cooperation architectures where the receiver is based on the IB-DFE (Iterative Block Decision Feedback Equalization) concept and we present a simple and accurate analytical model for obtaining the corresponding BER performance.1
7 citations
Cites background from "Frequency domain equalization for s..."
...SC-FDE schemes (Single-Carrier with Frequency domain Equalization) [5], [6] are preferable for the uplink (i....
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TL;DR: The designed AFD-DFE with CRLS not only enjoys a lower computational complexity when compared to the frequency-domain channel-estimate-based minimum mean square error DFE (MMSE DFE), but its performance is also better than that of the MMSE D FE with decision errors and is close to the MM SE DFE with correct decisions (ideal case).
Abstract: In this paper, we develop a constraint-based block recursive least-squares (CRLS) for an adaptive frequency-domain decision feedback equalizer (AFD-DFE) in uplink single-carrier frequency division multiple access systems. For the AFD-DFE, both the feedforward and feedback filters are implemented in the frequency domain; therefore, the CRLS complexity can be reduced substantially when compared to its time-domain counterpart by exploiting the matrix structure in the frequency domain. The performance of the CRLS algorithm is better than that of the RLS when applied to the AFD-DFE, with no increase in the computational complexity. Our designed AFD-DFE with CRLS not only enjoys a lower computational complexity when compared to the frequency-domain channel-estimate-based minimum mean square error DFE (MMSE DFE), but its performance is also better than that of the MMSE DFE with decision errors (practical case) and is close to the MMSE DFE with correct decisions (ideal case). Moreover, we iteratively compensate the transmitter and receiver phase noise using its properties in the time and frequency domains. Simulation results demonstrate the robustness of our designed AFD-DFE using CRLS.
7 citations
Cites background from "Frequency domain equalization for s..."
...Various nonadaptive structures of DFE already exist in the literature [3]–[8]....
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01 Oct 2008
TL;DR: In this paper, the performance of the bit-interleaved frequency-domain turbo equalization (Bi-FDTE) with spatial diversity over experimental underwater acoustic (UWA) channels was investigated.
Abstract: We investigate the performance of the bit-interleaved frequency-domain turbo equalization (Bi-FDTE) with spatial diversity over experimental underwater acoustic (UWA) channels. Our receiver combines the frequency domain minimum mean square error (MMSE) equalization with the soft interference cancellation with the bit-interleaved turbo equalization. Pilot symbols are periodically inserted and multiplexed with data symbols similar to that of the orthogonal frequency division multiplexing (OFDM). We test our transmission system over a real UWA channel environment conducted at Narragansett Bay, RI. We develop three different transmission scenarios to investigate performance/data rate tradeoff. Results from the experiment show that without spatial diversity the bit error rate (BER) reaches 10-4 at the 5th iteration when signal-to-noise ratio is equal to 18.3 dB at 3.71 kbps data rate. The BER performance is improved by exploiting the spatial diversity of the UWA channels by combining and equalizing data from multiple receive channels.
7 citations
Cites background or methods from "Frequency domain equalization for s..."
...Recently, single-carrier with frequency domain equalization (SC-FDE), [4] has gain widespread attentions in UWA....
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...Several papers have investigated the performance of SC-FDE using the minimum mean square error (MMSE) [5] and decision feedback equalizer (DFE) equalizer [4], [6], [7] where DFE exhibits superior performance at higher computational complexity....
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01 Jan 2011
TL;DR: This paper investigates the impact of the correlation factor estimation in the performance of iterative block decision feedback equalization (IB-DFE) receivers, and presents several methods to estimate the correlation coefficient.
Abstract: single-carrier (SC) modulation with frequency-domain equalization (FDE) combined with iterative (turbo) FDE schemes has been shown to be suitable for cyclic-prefix (CP)-assisted block transmission within broadband wireless systems. Its excellent performance in severely time-dispersive channels, makes it a promising candidate for future broadband wireless systems. In this paper we investigated the impact of the correlation factor estimation in the performance of iterative block decision feedback equalization (IB-DFE) receivers. Since the correlation factor represents a key parameter to ensure the good performance of these receivers, reliable estimates of this factor are needed in the feedback loop. We present several methods to estimate the correlation coefficient. We also propose a technique to compensate the inaccuracy of the estimation.
7 citations
Cites background or methods from "Frequency domain equalization for s..."
...However, the OFDM signals have high envelope fluctuations and a high peak-to-mean envelope power ratio (PMEPR) leading to amplification difficulties....
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...The performances and overall implementation complexities are similar to SC-FDE and OFDM [1, 2]....
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...The most popular techniques based on this concept are orthogonal frequency division multiplexing (OFDM) and single-carrier with frequency-domain equalization (SC-FDE)....
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...An alternative to OFDM modulations are SC modulations using FDE and CP-assisted block transmission techniques, especially for the uplink of broadband wireless systems [1, 2]....
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...It is known that block transmission techniques, with appropriate cyclic extensions and employing FDE techniques, are excellent candidates for severely time-dispersive channels [1, 2]....
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TL;DR: Simulation and field measurements indicate that the proposed Speed Determination (SD) Algorithm can effectively report the vehicle speeds of two-way roads.
Abstract: Telematics typically utilizes vehicle detectors and Global Positioning System (GPS)-based vehicle probes to compute the speeds of vehicles. When the detectors and the GPS probes are not available, vehicle speeds can be estimated by the cellular floating vehicle data technique, where the telecom network needs to spend extra effort to identify specific users and track their movements. This paper proposes the Speed Determination (SD) Algorithm, which uses standard statistics of telecom switches to compute the speeds of vehicles without extra effort in the telecom network. Simulation and field measurements indicate that the SD Algorithm can effectively report the vehicle speeds of two-way roads.
7 citations
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