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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01 Feb 2014
TL;DR: The proposed modulation scheme combines the advantages of known technologies and devoid of their shortcomings and is developed based on a study known SC-FDMA, OFDM and SC-FDE technologies.
Abstract: In this paper, we propose a modulation scheme, which can improve the performance of a variety of wired and wireless communication systems. We call this scheme "Single Carrier Multi-Tone" (SCMT) because it is a name well describes the physical principles on which it is made. This scheme was developed based on a study known SC-FDMA, OFDM and SC-FDE technologies. The aim of this research was to improve the performance of existing communication systems for terrestrial television broadcasting. The proposed modulation scheme combines the advantages of known technologies and devoid of their shortcomings. The several key characteristics of the SCMT are illustrated by the results of MATLAB simulation.
1Â citations
Patent•
26 Nov 2019TL;DR: In this article, a symbol detection and forward error correction (FEC) decoding system and method are presented that aim to increase decoding performance and maintain an acceptable level of complexity, in one embodiment, the method includes performing detection and decoding over a plurality of iterations, during the first iteration, a first equalizer structure processes a received signal, and a FEC decoder performs decoding on an input obtained from the output of the first equivalence structure.
Abstract: A symbol detection and forward error correction (FEC) decoding system and method are disclosed that aim to increase decoding performance and maintain an acceptable level of complexity. In one embodiment, the method includes performing detection and decoding over a plurality of iterations. During the first iteration: a first equalizer structure processes a received signal, and a FEC decoder performs decoding on an input obtained from the output of the first equalizer structure. During the other iterations: an iterative equalizer structure processes both (i) the received signal and (ii) an input obtained from an output of the FEC decoder from a previous iteration of the detection and decoding, in order to generate an output of the iterative equalizer structure, and the FEC decoder performs FEC decoding on an input obtained from the output of the iterative equalizer structure.
1Â citations
TL;DR: Simulation results show that the BER performance of proposed system is better than DMT-FMT system, and more suitable for the uplink Multiple-Access Channel.
Abstract: In this paper, a novel wireless transmission system is proposed. The system is composed of two cascaded subsystem: an inner filtered multitone (FMT) modulator with transmission over multiple antennas, and an outer Single carrier cyclic prefix (SCCP) system. The FMT modulator can efficiently avoid the inter-carrier interference, and with multiple antennas the cyclic delay diversity (CDD) can increase frequency-selectivity by inserting virtual echoes into the effective channel, and thus enhances the diversity of the system. The SCCP subsystem copes with the residual subchannel intersymbol interference. Simulation results show that the BER performance of proposed system is better than DMT-FMT system, and more suitable for the uplink Multiple-Access Channel.
1Â citations
Cites result from "Frequency domain equalization for s..."
...SCCP [10] system also known as Single-carrier Frequencydomain equalization (SCFDE) has similar structure and performance as OFDM....
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14 Jul 2011
TL;DR: In this article, the authors proposed a spectrum mapping technique, in which a predetermined part of spectrum is intentionally discarded and the non-discarded spectrum is mapped onto frequencies with high channel gains and transmitted to the destination node.
Abstract: Aiming at improving end-to-end channel capacity of an amplify-and-forward relay system under frequency se- lective fading channels, this paper proposes a spectrum mapping technique, in which a predetermined part of spectrum is intentionally discarded and the non-discarded spectrum is mapped onto frequencies with high channel gains and transmitted to the destination node , while order of the non-discarded spectrum is kept unchanged so that de-mapping can be conducted in a blind fashion. Since the proposed scheme intentionally discards the predetermined part of spectrum and transmits the non-discarded spectrum over frequencies with high channel gains in every link, frequency selection diversity gain can be ob- tained and the end-to-end channel capacity of the relay system can be enhanced. Distortion caused by discarding of a part of spectrum is compensated for with the aid of nonlinear equalization or channel decoding techniques. Furthermore, because information needed by coordination signaling is solely indices of deployed frequencies in each link, overhead can be sub- stantially suppressed. Numerical results reveal that the proposed spectrum mapping achieves almost the same capacity with
1Â citations
Cites methods from "Frequency domain equalization for s..."
...At D-node, frequency domain soft-canceller with minimum mean square error (SC/MMSE) equalizer [17] (with number of iterations is 16) is employed to detect information bits even in the case some frequency spectrum components of the block have been discarded by S-node and R-node [16]....
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...A half-rate non systematic convolutional (NSC) encoder with its generator polynomial of [15, 17]oct is employed as a channel decoder....
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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.
16,062Â 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.
2,627Â 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. >
1,816Â 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.
1,624Â citations