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
More filters
05 Sep 2004
TL;DR: Simulation results show that SC-FDE for CPM is an effective approach for C PM on channels having long impulse responses.
Abstract: Frequency-domain equalization for continuous phase modulation (CPM) is investigated. A discrete representation of the CPM signal is obtained by using the Gram-Schmidt orthonormalization procedure. The CPM discrete signal representation admits frequency-domain equalization for the purpose of mitigating intersymbol interference. General full- and partial-response CPM waveforms, and specific examples of MSK and GMSK with BT=0.3 are considered. Frequency-domain equalization is shown to be effective for CPM on severe frequency-selective fading channels.
72 citations
Cites methods from "Frequency domain equalization for s..."
...[5], Falconer and Ariyavisitakul [14]....
[...]
...This technique, called singlecarrier frequency-domain equalization (SC-FDE) [3]–[5], adds a cyclic guard interval to the transmitted signal similar to that used with OFDM....
[...]
Patent•
29 Jun 2007TL;DR: In this paper, the authors describe switching between various combinations of MIMO, SIMO, SISO and OFDM, LFDM and IFDM using a first set of data information.
Abstract: Systems and methodologies are described that facilitate switching between various combinations of MIMO, SIMO, SISO and OFDM, LFDM and IFDM. According to various aspects, a method for a wireless communication network is provided that includes: receiving a first set of data information, wherein the first set of information comprising a first value, determining if the first value is above a threshold and transmitting an indication to switch to using a first transmission technique if determined that the first value is above the threshold.
71 citations
TL;DR: A new variant of a block transmission based on 4-Weighted Fractional Fourier Transform (4-WFRFT), which contains a compatible process of single-carrier (SC) and multi-car carrier (MC) modulation, which could achieve a better performance than or equal to those of SC and MC systems in selective fading channels.
Abstract: We propose a new variant of a block transmission based on 4-Weighted Fractional Fourier Transform (4-WFRFT), which contains a compatible process of single-carrier (SC) and multi-carrier (MC) modulation. The 4-WFRFT system has an even and symmetrical bit energy distribution on the timefrequency plane that it could achieve a better performance than or equal to those of SC and MC systems in selective fading channels. The approach of 4-WFRFT may facilitate unification of the two competitive carrier schemes, and improve the distortion resistance capability of communication system.
71 citations
Cites background or methods from "Frequency domain equalization for s..."
...With respect to the competition of SC and MC, Falconer proposed a coexistent system of OFDM and SC-FDE in [2]....
[...]
...THERE has always been a fierce competition between single-carrier (SC) scheme and multi-carrier (MC) scheme, especially after the appearance of SC system with frequency domain equalization (SC-FDE) [1], [2]....
[...]
...For SC scheme with receiver decisions in time domain, the performance degradation due to a deep notch in the signal spectrum remains small with respect to that suffered by OFDM with receiver decisions in frequency domain [1], [2]....
[...]
...On the one hand, SC-FDE outperforms OFDM in multipath fading channels with deep notch in the signal spectrum [1], [2]....
[...]
...By analogy with OFDM [3], [4] and SC-FDE [1], [2], we find that “Subchannel 1” and “Subchannel 3” achieve an OFDM modulation process of the information sequence actually, since there is a DFT or IDFT module; while “Subchannel 0” and “Subchannel 2”, which have no DFT or IDFT module, achieve a traditional single-carrier modulation process....
[...]
TL;DR: Further modifications of DFT-S-OFDM are presented that offer improvements in flexibility and the latest enabling techniques on this topic are discussed.
Abstract: Discrete Fourier transform spread orthogonal DFT-S-OFDM, adopted in 3GPP LTE uplink, enables the synthesis of block-based single carrier waveforms with various bandwidths by changing the size of the DFT-spread block. Conceptually, it also allows a transition between block-based multicarrier and single-carrier schemes when multiple DFT-spread blocks are employed in the structure. Recently, it has been shown that DFT-S-OFDM can also accommodate an internal guard period that offers flexibility on the duration of the guard periods without affecting the symbol duration. In this article, we present further modifications of DFT-S-OFDM that offer improvements in flexibility and discuss the latest enabling techniques on this topic. Considering the flexibility introduced by DFTs-OFDM and its variations, the DFT-S-OFDM family also offers a set of promising waveforms for 5G networks, which will require a flexible physical layer.
70 citations
Cites methods from "Frequency domain equalization for s..."
...We set the modulation as 64-QAM and use a single-tap MMSE-FDE receiver that allows the receiver to the exploit the path diversity for SC systems [11]....
[...]
Book•
01 Oct 2010TL;DR: In this article, the authors provide a review of basic digital communication, starting from the equivalent discrete time channel and including a detailed review of the MMSE receiver, and extensive performance analysis of OFDM and DMT systems, with discussions of many practical issues such as implementation and power spectrum considerations.
Abstract: Providing key background material together with advanced topics, this self-contained book is written in an easy-to-read style and is ideal for newcomers to multicarrier systems. Early chapters provide a review of basic digital communication, starting from the equivalent discrete time channel and including a detailed review of the MMSE receiver. Later chapters then provide extensive performance analysis of OFDM and DMT systems, with discussions of many practical issues such as implementation and power spectrum considerations. Throughout, theoretical analysis is presented alongside practical design considerations, whilst the filter bank transceiver representation of OFDM and DMT systems opens up possibilities for further optimization such as minimum bit error rate, minimum transmission power, and higher spectral efficiency. With plenty of insightful real-world examples and carefully designed end-of-chapter problems this is an ideal single-semester textbook for senior undergraduate and graduate students, as well as a self-study guide for researchers and professional engineers.
68 citations
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]....
[...]
...Overlap-save or overlap-add signal processing techniques could also be used to avoid the extra overhead of the cyclic prefix [Fer85], [Hay96]....
[...]
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 ]....
[...]
...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 ]....
[...]
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