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 2014
TL;DR: Energy models for a point-to-point wireless transmission that consider practical aspects such as multipath fading, error-control coding and receiver synchronization are developed and results show that there exists an optimal parameter configuration that gives the minimum energy consumption for given data and bit-error rates.
Abstract: Conventional research on energy-efficient wireless systems tends to focus on saving transmit energy. However, as the evolution of wireless systems moves towards shorter distance transmission and smaller cell sizes, the computational energy in wireless hardware becomes significant alongside transmit radio energy. In this paper, we develop energy models for a point-to-point wireless transmission that consider practical aspects such as multipath fading, error-control coding and receiver synchronization. The total energy consumption of the wireless system is modeled as a function of modulation scheme, data rate, signal bandwidth, code rate, received signal-to-noise ratio (SNR) and channel parameters. We choose a multipath Rayleigh-fading channel model and Reed-Solomon coding scheme for the numerical analyses. Simulation results show that there exists an optimal parameter configuration that gives the minimum energy consumption for given data and bit-error rates. At short transmission distances, computational energy dominates and higher-order modulation schemes with low bandwidth allocation are shown to be more energy efficient.
Cites methods from "Frequency domain equalization for s..."
...We employ a frequency-domain equalizer (FDE) due to its lower computational complexity compared to time-domain equalizers when the number of channel taps is large [11]....
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01 Dec 2005
TL;DR: Computer simulation shows that the proposed block transmission system with frequency-domain equalization (SC-FDE) aided by the insertion of cyclic prefix can provide diversity benefit as the non-differential system does, while greatly reducing the receiver complexity.
Abstract: In this paper, we propose a new differential multiple-input multiple-output (MIMO) single-carrier system with frequency-domain equalization (SC-FDE) aided by the insertion of cyclic prefix. This block transmission system not only inherits all the merits of the single-input single-output (SISO) SC-FDE system, but is also equipped with a differential space-time block coding (DSTBC) such as to combat the fast-changing frequency selective fading channels without the needs to estimate and then compensate the carrier frequency offset and channel effects. Hence, for practical applications, it has the additional merits of decoding simplicity and robustness against difficult transmission environments. Computer simulation shows that with two transmit antennas, the proposed system can provide diversity benefit as the non-differential system does, while greatly reducing the receiver complexity.
Cites background from "Frequency domain equalization for s..."
...Moreover, it has some additional benefits like low envelope fluctuations and transmitter simplicity [1]-[2]....
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01 Jun 2011
Abstract: This paper deals with multiple-input multiple-output communication system with single-carrier modulation and frequency domain equalization. Space-time coding schemes adapted to frequency-selective channels namely space-time block codes per block are used. An efficient generalized receiver based on space-time frequency domain detector is investigated. We propose the frequency domain derivation of a generalized minimum mean square error turbo equalizer for orthogonal space-time block code per block. The main advantage of our proposed scheme is that it can be applied to any orthogonal space-time block code per block. Simulation results show that the scheme performs efficiently over frequency-selective block fading channels.
20 Mar 2003
TL;DR: A new single carrier cyclic prefix assisted multiple access scheme for the asynchronous broadband CDMA system in uplink is suggested, which can reach the similar performance of the serial type while reducing the processing delay greatly.
Abstract: In this paper we suggest a new single carrier cyclic prefix assisted multiple access scheme for the asynchronous broadband CDMA system in uplink. Frequency domain equalization is applied instead of conventional RAKE combining or time domain equalization. A new serial type multistage interference cancellation in frequency domain is proposed to cancel the multiple access interference while keeping low computational complexity. We also investigated the effects of interference rejection weight control for this multistage interference cancellation. Another hybrid system combining the successive interference cancellation and parallel interference cancellation is also proposed, which can reach the similar performance of the serial type while reducing the processing delay greatly.
Cites background or methods from "Frequency domain equalization for s..."
...Moreover, Single-carrier modulation is a well-proven technology in many existing wireless and wireline application and its radio frequency system linearity requirements are well known [2]....
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...That is because single carrier CDMA with FDE has essentially similar structure as MC-CDMA....
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...Frequency domain equalization is computationally simpler than corresponding time domain equalization for a channel with severe multipath fading [2]....
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...That is because single carrier CDMA with FDE has essentially similar structure as MC-CDMA.[2]....
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...By combining the traditional single-carrier modulation and FDE method, SCRIP-CDMA can get similar performance with MC-CDMA while reducing the peak-to-average power greatly, which in turn means cheaper power amplifier for the system [2]....
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TL;DR: This letter shows that part of the IFFT in the transmitter of an OFDM system can be shifted to the receiver, while a conventional one-tap frequency-domain equalizer is still applicable, and proposes two I FFT split schemes based on decimation-in-time and decimation in-frequency algorithms to enable interference-free symbol recovery with simple linear equalizers.
Abstract: This letter extends our previous work on layered inverse Fast Fourier Transform (IFFT) structure to a multistage layered IFFT structure where data symbols can input at different stages of the IFFT. We first show that part of the IFFT in the transmitter of an OFDM system can be shifted to the receiver, while a conventional one-tap frequency-domain equalizer is still applicable. We then propose two IFFT split schemes based on decimation-in-time and decimation-in-frequency IFFT algorithms to enable interference-free symbol recovery with simple linear equalizers. Applications of the proposed schemes in multiple access communications are investigated. Simulation results demonstrate the effectiveness of the proposed schemes in improving bit-error-rate performance.
Cites methods from "Frequency domain equalization for s..."
...Based on the framework we proposed the asymmetric OFDM system which bridges conventional OFDM and single carrier with frequency domain equalization (SC-FDE) [2] systems....
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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