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 Nov 2014
TL;DR: This work has proposed an overlap FDE with coherent averaging that suppresses the residual interferences of the conventional overlapping FDE outputs and improves the equalization performance.
Abstract: Frequency domain equalization (FDE) has attracted a great deal of attention as a broadband wireless access technique. The conventional single-carrier (SC) method using FDE requires the insertion of a cyclic prefix (CP) as the guard interval (GI) to avoid inter-block interference (IBI). However, CP insertion reduces the transmission efficiency. On the other hand, overlap FDE is an equalization technique for use with the SC method that avoids the need for CP insertion. We have proposed an overlap FDE with coherent averaging that suppresses the residual interferences of the conventional overlap FDE outputs and improves the equalization performance. In the present study, we evaluate and compare the bit error rate (BER) performances of the SC using FDE with a CP and without a CP under the same transmission efficiency. Computer simulations demonstrate that the proposed scheme has superior performance to various modulation methods.
Cites background from "Frequency domain equalization for s..."
...One existing technology that boasts outstanding multipath robustness is single-carrier (SC) FDE, which is a block-based transmission scheme[1][2]....
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01 Jan 2015
TL;DR: In this paper, a single-carrier frequency domain equalization (SCFDE) combining with space time block coding (Alamouti like scheme) for linear equalizers achieves significant diversity gain at low computational complexity over frequency selective fading channel.
Abstract: In wireless communication, multipath propagation results in several fading effect. To equalize such long fading channel traditional single carrier time domain equalization becomes infeasible due to its large computational complexity. Single-carrier frequency- domain equalization (SCFDE) offers low complexity, minimum peak to average power ratio as well as less sensitive to carrier frequency offset compared with orthogonal frequency division multiplexing (OFDM). This paper provides SCFDE combining with space time block coding (Alamouti like scheme) for linear equalizers achieves significant diversity gain at low computational complexity over frequency selective fading channel. And compare performance of linear equalizers Zero Forcing and Minimum Mean Square Error with BPSK, QPSK and QAM modulation techniques. Also here showing that diversity depends not only on antenna configuration and channel memory but also on data block length and data transmission rate.The results are derived from MATLAB simulations are presented and discussed in the paper.
Cites background from "Frequency domain equalization for s..."
...Also SCFDE provides application for LTE uplink [1], [2]....
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10 Nov 2005
TL;DR: A frequency-domain adaptive interference cancellation (FDAIC) for multicode DSand MC-CDMA signal transmissions is proposed and their achievable BER performances are evaluated by computer simulation.
Abstract: Abstract Frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can significantly improve the bit error rate (BER) performance of direct sequence (DS-) and multicarrier (MC-) code division multiple access (CDMA) signal transmission in a severe frequency-selective fading channel. In 4G systems, much higher variable rate data services than in the present 3G systems are demanded. Orthogonal multicode DSand MC-CDMA have high flexibility in offering variable rate data service by simply changing the number of parallel orthogonal spreading codes. However, since the frequency-distorted signal cannot be completely equalized, the BER performance degrades due to the presence of the residual inter-code interference (ICI) as the number of parallel codes increases. In this paper, we propose a frequency-domain adaptive interference cancellation (FDAIC) for multicode DSand MC-CDMA signal transmissions and their achievable BER performances are evaluated by computer simulation. To avoid the negative effect of the error propagation due to decision feedback for the replica generation, the soft interference replica is generated by using log-likelihood ratio (LLR). Keyword DS-CDMA, MC-CDMA, frequency-domain equalization (FDE), inter-code interference, cancellation
Additional excerpts
...しかし,シングルキャリア伝送に FDE を用いれば,周波数ダイバーシチ効果を積極的 に利用でき,BER 特性を改善できることが分かって きた [4]....
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Journal Article•
TL;DR: 2×2 SC-MIMO £2,000,000; 2×2 QRM-MLBD ¬2,500; シンボル�’補 の絞り込み結果; アルゴリズ ムにおけるパスメトリック演算量;
Abstract: あらまし QR 分解と M アルゴリズムを用いる演算量削減型最尤ブロック信号検出法(QRM-MLBD)は,最尤検出 (MLD)から演算量を大幅に削減しつつ,最小二乗誤差規範に基づく空間フィルタリング(MMSED)に比べシングルキ ャリア(SC)マルチ送受信アンテナ(MIMO)多重伝送の伝送特性を大幅に改善できる.しかしながら,M アルゴリズ ムにおけるパスメトリック演算では,各ステージで全てのシンボル候補について計算を行うため,QRM-MLBD の 演算量は依然として大きい.そこでシングルアンテナ(SISO)伝送を対象に,筆者らは最近,MMSE 規範に基づく周 波数領域等化(MMSE-FDE)出力から事後確率を計算してシンボル候補を絞り込むことでパスメトリック演算量を削 減する 2 ステップ QRM-MLBD を提案した.本報告では,2 ステップ QRM-MLBD を用いる SC-MIMO 多重伝送を 対象に, シンボル候補の絞り込み結果と送信アンテナ順番とを考慮した適応オーダリング提案する.2×2 SC-MIMO 多重伝送の場合,適応オーダリングを導入した 2 ステップ QRM-MLBD は QRM-MLBD と同等のスルー プット特性を達成しつつ,演算量を QRM-MLBD のおよそ 1/30 まで削減できることを計算機シミュレーションによ り示す. キーワード シングルキャリア,MIMO,MLD,MMSED,QR 分解,M アルゴリズム
Additional excerpts
...Copyright ©2012 by IEICE られている．しかし，OFDM 伝送はピーク対平均信号 電力比 (PAPR)が大きくなるため，線形電力増幅器の負 担が増加してしまうという問題がある．そのため，近 年 PAPR の問題が少ないシングルキャリア (SC)伝送を 用いる MIMO 多重伝送 [4]が上りリンク伝送において 注目されている．少ない演算量で実現できる信号検出 法として最小平均二乗誤差規範に基づく空間フィルタ リング (MMSED)[5]があるが残留干渉成分による特性 劣化が大きく最尤検出 (MLD)[6]との特性差は大きく なってしまう．そこで最近，QR 分解と M アルゴリズ ム を 用 い る 演 算 量 削 減 型 最 尤 ブ ロ ッ ク 信 号 検 出 (QRM-MLBD)[7-9]が提案されているがその演算量は 依然として大きい．そこで筆者らは最近，MMSE 規範 に基づく周波数領域等化 (MMSE-FDE)[10,11]による事 前判定結果を利用してシンボル候補を絞り込み演算量 を削減する 2 ステップ QRM-MLBD[12-13]をシングル アンテナ (SISO)の SC 伝送における信号検出法として 提案した． 本報告では 2 ステップ QRM-MLBD を SC-MIMO 多 重伝送に拡張し，シンボル候補の絞り込み結果と送信 アンテナ順とを考慮した適応オーダリングを提案する． 適応オーダリングを用いる 2 ステップ QRM-MLBD は QRM-MLBD と同等のスループット特性を達成しつつ 演算量を大幅に削減できることを示す． 以下に本報告の構成を示す．第 2 章において 2 ステ ップ QRM-MLBD を用いる SC-MIMO 多重伝送につい て述べる．第 3 章では計算機シミュレーションにより， 適応オーダリングを導入した 2 ステップ QRM-MLBD を用いる SC-MIMO 多重伝送のスループット特性を明 らかにし，従来の QRM-MLBD と比較する．第 4 章に て本報告をまとめる． 2....
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...そこで筆者らは最近,MMSE 規範 に基づく周波数領域等化 (MMSE-FDE)[10,11]による事 前判定結果を利用してシンボル候補を絞り込み演算量 を削減する 2 ステップ QRM-MLBD[12-13]をシングル アンテナ (SISO)の SC 伝送における信号検出法として 提案した....
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01 Mar 2018
TL;DR: This paper investigates the method to combat the induced ISIs together with one equalizer at the receiver and demonstrates that acceptable BER system performance can be achieved with the proposed transceiver.
Abstract: When the Faster-than-Nyquis (FTN) signal transmits in the Single Carrier Frequency-Domain Equalization (SC-FDE) system over the multipath frequency selective channel, the Inter-Symbol Interferences (ISIs) will be induced by both FTN signaling and multipath channel. In this paper, we investigate the method to combat the induced ISIs together with one equalizer at the receiver. The simulation results demonstrate that acceptable BER system performance can be achieved with our proposed transceiver.
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