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 Oct 2016
TL;DR: This paper will elaborate from the following aspects: Mathematical expression of the integrated waveform in order to deduce the reason of spectrum extension and propose solutions accordingly, and the practicability of the method proposed by in this paper by implementing integrated wave form and algorithm on FPGA using VHDL language.
Abstract: Integration of radar and communication is an important trend in the future development of radar technology. The combination of radar and communication allows them to give full play of their respective superiority while make up for their deficiencies. As a result, the detection radar becomes communication radar, a network platform for information giving, which will immensely enhance the force of battle group. The key of Radar-communication integration is the design of integrated waveform. A practicable waveform is to modulate Minimum Shift Keying (MSK) signal onto Linear Frequency Modulation (LFM) signal, but the problem is the likelihood of leading to the extension of the spectrum, which will seriously affect the performance of radar detection and communication. To solve the problem, this paper will elaborate from the following aspects: 1. Mathematical expression of the integrated waveform in order to deduce the reason of spectrum extension and propose solutions accordingly. 2. Application of MATLAB in the simulation of spectrum extension [1] and result of limiting spectrum extension using the algorithm proposed in this paper. 3. The practicability of the method proposed by in this paper by implementing integrated waveform and algorithm on FPGA using VHDL language.
3Â citations
08 Sep 2014
TL;DR: By extensive computer simulation, this article presents a comprehensive performance comparison of OFDM-based schemes in a nonlinear and frequency-selective fading channel.
Abstract: Orthogonal Frequency Division Multiplexing is a wideband modulation scheme that is designed to cope with the problems of the multipath reception. Essentially, the wideband frequency selective fading channel is divided into many narrow-band sub channels. There has been greatly increasing interest in orthogonal frequency division multiplexing for broadband wireless transmission due to its robustness against multipath fading. In this article, by extensive computer simulation, we present a comprehensive performance comparison of OFDM-based schemes in a nonlinear and frequency-selective fading channel. In this paper design of OFDM system transmitter and receiver using frequency selective fading is introduced and to know the behavior we have done the simulation using MATLAB.
3Â citations
01 Dec 2018
3Â citations
01 Nov 2007
TL;DR: In this article, a cyclic-prefixed single-carrier (CP-SC) transmission is employed to operate at a wide signal bandwidth using low-order modulation, and a novel, fast equalization scheme for the channelized receiver based on a diversity combining perspective is described.
Abstract: A high-speed and low-power UWB radio system is proposed. To operate at a wide signal bandwidth using low-order modulation, cyclic-prefixed single-carrier (CP-SC) transmission is employed. CP-SC uses a simple transmitter structure and enables the use of efficient frequency domain equalizer at the receiver. As the UWB radio must co-exist with in-band and out-of-band interferers that are inevitably present in the unlicensed UWB band, the primary implementation challenge is the need to support the wide signal bandwidth in the presence of these interferers. To relax the resulting large dynamic range requirement of the radio, a frequency channelized UWB receiver is presented. A novel, fast equalization scheme for the channelized receiver based on a diversity combining perspective is described. Based on the AGC settings in each subband, the scheme automatically accounts for the effects of interferers when combining the subbands.
3Â citations
Cites background from "Frequency domain equalization for s..."
...To operate at the widest bandwidth possible using low-order modulation, a cyclic-prefixed single-carrier (CP-SC) transmission is used [1]....
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TL;DR: Simulation results demonstrate that channel estimation based on CS achieves a better bit error rate (BER) performance than time domain LS with a smaller pilot sequence and thus raising data rate of the SC communication system.
Abstract: In this paper, we compare the performance between channel estimation based on compressed sensing (CS) and time-domain least square (LS) for single-carrier (SC) communication system. Unlike the conventional channel estimation techniques such as frequency domain LS which is used in the condition that the length of pilot sequence is equal to data sequence, the estimation scheme based on CS requires smaller length of pilot sequence. In this paper, the corresponding system structure is presented. Zadoff-Chu sequence is used to generate the pilot sequence, which is shown to perform better in forming measurement matrix of CS than pseudo random sequence. Simulation results demonstrate that channel estimation based on CS achieves a better bit error rate (BER) performance than time domain LS with a smaller pilot sequence and thus raising data rate of the SC communication system.
3Â citations
Cites methods from "Frequency domain equalization for s..."
...At the receiver, after removing CP, channel estimation, frequency domain equalization which is the frequency domain analog of what is done by a conventional time domain equalizer[3], we obtain the estimated data symbols....
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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.
16,062Â 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