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
25 Sep 2005
TL;DR: This two-layer spreading CDMA (TLS-CDMA) system can combat multiple-access interference (MAI) and multipath interference (MPI) simultaneously and effectively in a multiuser scenario over frequency-selective fading channels.
Abstract: This paper describes a novel type of code division multiple access (CDMA) system, two-layer spreading CDMA (TLS-CDMA). It can combat multiple access interference (MAI) and multipath interference (MPI) efficiently over frequency selective fading channels. Moreover, a two-layer cell-specific scrambling code is proposed for the TLS-CDMA system in the uplink transmission to suppress other-cell interference (OCI). The proposed TLS-CDMA system enables the spreading factor to be adapted to the cell structure and channel propagation conditions to support variable data rate transmission among multiple pseudo-synchronous users. The simulation results show the superior of the proposed TLS-CDMA system over the existed uplink transmission systems.
7 citations
01 Sep 2006
TL;DR: This paper provides a sufficient condition for LDC-CP-SCM to maximize all available joint frequency and time diversity gain and coding gain, and shows that LDC with forward error correction (FEC) may outperform CP- SCM with FEC over time.
Abstract: Linear dispersion coded orthogonal frequency division multiplexing (LDC-OFDM) has recently been proposed to improve joint frequency and time diversity. This paper investigates whether LDC are able to support joint frequency and time diversity for single-carrier block communications in time-varying frequency selective fading channels, and proposes linear dispersion coded cyclic-prefix single-carrier modulation (LDC- CP-SCM), which utilizes LDC across multiple CP-SCM blocks. LDC-CP-SCM uses a layered two-stage LDC decoding strategy, and is thus backwards-compatible to CP-SCM systems. This paper analyzes the diversity properties of LDC-CP-SCM, and provides a sufficient condition for LDC-CP-SCM to maximize all available joint frequency and time diversity gain and coding gain. For the LDC considered, simulations show that with and without carrier frequency offset (CFO) effects, LDC-CP-SCM may outperform both CP-SCM and LDC-CP-OFDM in time- varying frequency selective channels. This paper also shows that LDC-CP-SCM with forward error correction (FEC) may outperform CP-SCM with FEC over time.
7 citations
19 May 2008
TL;DR: The proposed relay-based transmit diversity technique for single carrier frequency-domain equalization achieves spatial diversity over fading channels in a distribution fashion without cyclic prefix (CP), which increases spectral efficiency of conventional relay- based systems.
Abstract: This paper proposes a relay-based transmit diversity technique for single carrier frequency-domain equalization (SC-FDE). The proposed system achieves spatial diversity over fading channels in a distribution fashion without cyclic prefix (CP), which increases spectral efficiency of conventional relay- based systems. The destruction of channel cyclicity due to the lack of CP is recovered at the input of relay and destination. In order to obtain spatial diversity, the transmit sequence of relay is efficiently generated in time domain, realizing space-frequency block code (SFBC). Corresponding destination structure using FDE, timing synchronization, and highly accurate channel estimation for the proposed system are also presented. Simulation results show that the proposed system approaches the lower bound of full-CP system.
7 citations
Cites background from "Frequency domain equalization for s..."
...Index Terms - SC-FDE, CP, relay, SFBC. I. INTRODUCTION Single-carrier frequency-domain equalization (SC-FDE) has similar performance and essentially the same overall complexity as orthogonal frequency division multiplexing (OFDM) [1]....
[...]
...Recently, the SC-FDE has drawn a great attention as an alternative to the OFDM, especially in the uplink communications, because its transmit structure at mobile equipment is very simple and lower peak-to-average power ratio (PAPR) significantly benefits the transmitter in terms of power efficiency....
[...]
...INTRODUCTION Single-carrier frequency-domain equalization (SC-FDE) has similar performance and essentially the same overall complexity as orthogonal frequency division multiplexing (OFDM) [1]....
[...]
Dissertation•
14 Sep 2011
TL;DR: In this paper, an analisis matematico de las prestaciones de SC-FDMA en terminos de BER and eficiencia espectral cuando se emplea esta tecnologia for transmitir sobre un canal con desvanecimiento selectivo en frecuencia.
Abstract: SC-FDMA se ha convertido en una atractiva alternativa a OFDMA debido a su baja PAPR. Esta caracteristica ha hecho que fuera elegida para su implantacion en el enlace ascendente en la especificacion LTE del 3GPP. En esta tesis se realiza un analisis matematico de las prestaciones de SC-FDMA en terminos de BER y eficiencia espectral cuando se emplea esta tecnologia para transmitir sobre un canal con desvanecimiento selectivo en frecuencia. Tambien se ha comprobado la adecuacion de las expresiones cerradas para aproximar valores reales de BER obtenidos para modelos de canales realistas definidos por la ITU y el 3GPP.
7 citations
16 May 2010
TL;DR: This paper considers SC-HARQ using joint transmit/receive MMSE-FDE and derive a suboptimal set of transmit and receive FDE weights for packet combining and shows by computer simulation that the joint transmit / receive MMSE/FDE offers improved throughput.
Abstract: In the next generation high-speed wireless packet access systems, hybrid automatic repeat request (HARQ) is necessary to achieve higher throughput performance. An HARQ with Chase combining (CC) transmits the same coded packet until it is correctly received. The received packets are combined to achieve the time-diversity gain. Recently, we proposed a joint transmit/receive frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion for a broadband single-carrier (SC) signal transmission in a frequency-selective channel. In this paper, we consider SC-HARQ using joint transmit/receive MMSE-FDE and derive a suboptimal set of transmit and receive FDE weights for packet combining. We show by computer simulation that the joint transmit/receive MMSE-FDE offers improved throughput compared to the conventional receive MMSE-FDE.
7 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