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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28 Sep 2005
TL;DR: This paper proposes a frequency-domain multi-stage MAI cancellation for DS-CDMA uplink with transmit/receive antenna diversity and evaluates the achievable BER performance by computer simulation.
Abstract: As the number of resolvable propagation paths increases, the bit error rate (BER) performance of DS-CDMA with rake combining degrades due to increasing inter-path interference. Recently, we have shown that the use of frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can significantly improve the downlink BER performance. However, for the uplink transmissions, MAI (multi-access interference) is produced due to orthogonality destruction among users and the uplink BER performance severely degrades. In this paper, we propose a frequency-domain multi-stage MAI cancellation for DS-CDMA uplink with transmit/receive antenna diversity and evaluate the achievable BER performance by computer simulation.
6 citations
Cites background from "Frequency domain equalization for s..."
...However, recently DS-CDMA has been considered over again with the application of frequency-domain equalization (FDE) [3]....
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TL;DR: This study considers cooperative transmission in cognitive wireless relay networks (CWRNs) over frequency-selective fading channels and proposes a new distributed space-time–frequency block code (DSTFBC) to achieve spatial diversity gain and allow for low-complexity decoupling detection at the receiver.
Abstract: In this study, the authors consider cooperative transmission in cognitive wireless relay networks (CWRNs) over frequency-selective fading channels. They propose a new distributed space-time–frequency block code (DSTFBC) for a two-hop non-regenerative CWRN, where a primary source node and multiple secondary source nodes convey information data to their desired primary destination node and multiple secondary destination nodes via multiple cognitive relay nodes with dynamic spectrum access. The proposed DSTFBC is designed to achieve spatial diversity gain as well as allow for low-complexity decoupling detection at the receiver. Pairwise error probability is then analysed to study the achievable diversity gain of the proposed DSTFBC for different channel models including Rician fading and mixed Rayleigh–Rician fading.
6 citations
TL;DR: This letter proposes a unique word (UW) based FDE-NP (FDE- NP- UW) that can yield better performance and both optimal and suboptimal designs of the FDE -NP-UW are presented.
Abstract: Recently, the frequency domain equalization with time domain noise prediction (FDE-NP) has been proposed as an alternative to hybrid decision feedback equalization (HDFE). The current FDE-NP structures use the cyclic prefix (CP) extension (FDE-NP-CP). However, the unknown nature of CP degrades the performance of FDE-NP due to error propagation. This letter proposes a unique word (UW) based FDE-NP (FDE-NP-UW) that can yield better performance. Both optimal and suboptimal designs of the FDE-NP-UW are presented. We observe that the optimal FDE-NP-UW provides a performance gain of about 1.5 dB over the FDE-NP-CP, and about 0.5 dB over the suboptimal design at a BER of 10-3.
6 citations
Cites background or methods from "Frequency domain equalization for s..."
...The former inserts a CP in front of each data block [1], and the latter adds a known sequence to the tail of each data block [4]....
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...Single-carrier frequency domain equalization (SC-FDE) [1] is a promising alternative that can avoid disadvantages of ODFM systems and provide similar performance and complexity....
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...In [1], [4], the hybrid decision feedback equalization (HDFE) was proposed but it is not easy to efficiently combine the decoder and feedback filtering in coded systems [5]....
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TL;DR: A novel iterative channel estimation approach is proposed for cyclic prefix–code division multiple access systems using code-multiplexed pilots for channel estimation while maintaining bandwidth efficiency and achieves a significant improvement when compared to the conventional correlation approach.
Abstract: A novel iterative channel estimation approach is proposed for cyclic prefix–code division multiple access systems. Code-multiplexed pilots are used for channel estimation while maintaining bandwidth efficiency. The proposed method achieves a significant improvement when compared to the conventional correlation approach by reconstructing data signals for channel estimation. Simulation results demonstrate good estimation capability with an allocation of only 10% of the whole power to the pilot channel. In addition, an integrated channel estimator and parallel interference cancellation (PIC) detector are proposed. Data signals are reconstructed for channel estimation while the interference contributed by different data channels as well as the pilot channel are regenerated and subtracted from the received signal at the final stage. The channel estimation error reduces at each iteration and the PIC at the last stage enables further bit error rate performance improvement to be achieved for the system. The performance of the proposed scheme is studied through simulations and results verify its effectiveness.
6 citations
26 May 2008
TL;DR: This paper proposes novel iterative algorithms for estimating the channel impulse response (CIR) in SC block transmission systems by exploiting a unique word (UW) extension and results show that the proposed channel estimation method brings good BER performance with fast convergence over frequency-selective slowly fading channels.
Abstract: Accurate channel estimation is essential for coherent single-carrier (SC) block transmission systems. In this paper, we propose novel iterative algorithms for estimating the channel impulse response (CIR) in SC block transmission systems by exploiting a unique word (UW) extension. The interference caused by the data to the UW is removed from the received signal by first equalizing the data using a previous channel estimate, and then subtracting the estimated interference signal from each received signal block. Erasure decision is used to improve the performance and the effects of error propagation is reduced. Simulation results show that the proposed channel estimation method brings good BER performance with fast convergence over frequency-selective slowly fading channels.
6 citations
Cites background from "Frequency domain equalization for s..."
...Single-carrier (SC) transmission with frequency-domain equalization (FDE) is a promising technique for high data rate communications due to its simple implementation and robustness to frequency-selective fading channel [1]....
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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