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
Posted Content•
TL;DR: Simulations show that the proposed equalization algorithms outperform the existing reduced-rank and full-rank algorithms, while requiring a comparable computational cost.
Abstract: This paper presents a novel adaptive reduced-rank {multi-input multi-output} (MIMO) equalization scheme and algorithms based on alternating optimization design techniques for MIMO spatial multiplexing systems. The proposed reduced-rank equalization structure consists of a joint iterative optimization of two equalization stages, namely, a transformation matrix that performs dimensionality reduction and a reduced-rank estimator that retrieves the desired transmitted symbol. The proposed reduced-rank architecture is incorporated into an equalization structure that allows both decision feedback and linear schemes for mitigating the inter-antenna and inter-symbol interference. We develop alternating least squares (LS) expressions for the design of the transformation matrix and the reduced-rank estimator along with computationally efficient alternating recursive least squares (RLS) adaptive estimation algorithms. We then present an algorithm for automatically adjusting the model order of the proposed scheme. An analysis of the LS algorithms is carried out along with sufficient conditions for convergence and a proof of convergence of the proposed algorithms to the reduced-rank Wiener filter. Simulations show that the proposed equalization algorithms outperform the existing reduced-rank and full-rank algorithms, while requiring a comparable computational cost.
3 citations
Cites methods from "Frequency domain equalization for s..."
...communications systems with guard intervals including those based on orthogonal frequency-division multiplexing (OFDM) [37], [38] and single-carried (SC) modulation with frequency-domain equalization [39]. Consider a MIMO system with NT antennas at the transmitter and NR antennas at the receiver in a spatial multiplexing configuration, as shown in Fig. 1. The system is mathematically equivalent to that...
[...]
16 May 2010
TL;DR: An efficient sphere decoding algorithm (SDA) applied to solve the inter-symbol-interference (ISI) data detection problem is proposed and can perform at least 1.5dB better than frequency- domain equalizers under the environment of randomly generated channel impulse responses.
Abstract: In this paper, an efficient sphere decoding algorithm (SDA) applied to solve the inter-symbol-interference (ISI) data detection problem is proposed. This proposed algorithm takes advantages of the SDA to obtain the solution close to ML solution with the simplified K-best tree search method for the ISI data detection under ISI effect. Compared with the frequency-domain MMSE or Zero-Forcing equalization techniques for SCBT (Single-Carrier Block Transmission) systems, this algorithm can perform at least 1.5dB better than frequency- domain equalizers under the environment of randomly generated channel impulse responses.
3 citations
Cites background from "Frequency domain equalization for s..."
...With the advancement of the single-carrier (SC) communication system, a new transmit data format named single-carrier block transmission (SCBT) has been proposed [1]....
[...]
09 Feb 2014
TL;DR: A solution for joint equalization and phase drift compensation for the underwater acoustic (UWA) channel aimed at compensating the vehicular component of the Doppler effect is presented.
Abstract: In this paper we present a solution for joint equalization and phase drift compensation for the underwater acoustic (UWA) channel. In particular, we aim at compensating the vehicular component of the Doppler effect. This component is modeled resorting to a random walk model with a linear drift. It will be estimated using a Bayesian filtering technique, namely, the sequential importance sampling (SIS) algorithm, also known as particle filter (PF). The equalization will be attained using an iterative frequency-domain equalizer (IFDE). Performance results, obtained using state-of-the-art UWA channel models, are presented.
3 citations
Cites background from "Frequency domain equalization for s..."
...SC-FDE schemes have implementation complexities similar to OFDM, but smaller envelope fluctuations, leading to a simpler signal amplification [6], [7], and they are less sensitive to CFOs [8]....
[...]
04 Dec 2014
TL;DR: This paper evaluates, by computer simulation, the average bit error rate (BER) performance of PBCSC-FDE and shows that its achievable BER performance is superior to a 2-step decoding which performs FDE and hard decision block decoding separately.
Abstract: In this paper, we propose a pseudo block-coded SC transmission with frequency-domain equalization (FDE). We call this scheme as pseudo block-coded SC with FDE (PBCSC-FDE). A concatenation of block encoding matrix, interleaving matrix, DFT matrix, mapping matrix and channel matrix can be viewed as an equivalent MIMO channel and FDE and block decoding can be jointly performed based on the minimum mean square error (MMSE) criterion. We evaluate, by computer simulation, the average bit error rate (BER) performance of PBCSC-FDE and show that its achievable BER performance is superior to a 2-step decoding which performs FDE and hard decision block decoding separately.
2 citations
Cites background from "Frequency domain equalization for s..."
...The minimum mean square error (MMSE) based frequency-domain equalization (FDE) is an effective scheme to overcome the frequency-selective fading [2-4]....
[...]
18 Jun 2009
TL;DR: The future of SC-FDE and PAPR is in doubt because of uncertainty over the US-China trade deal.
Abstract: あらまし 広帯域シングルキャリア(SC)信号はピーク対平均電力比(PAPR)が小さく,上りリンク(移動局→基地 局)伝送に適している.平均二乗誤差(MMSE)規範に基づく周波数領域等化(FDE)を用いれば,周波数ダイバーシチ効 果が得られ,優れた伝送特性を実現できる.符号間干渉を起こさずに信号帯域幅を制限するために,送信および受 信フィルタにルートナイキストフィルタが広く用いられている.SC-FDE に関するこれまでの検討の殆どがシンボ ル間隔の離散信号表現を用いており,フィルタのロールオフファクタ α が PAPR 及びビット誤り率(BER)特性にど のような影響を及ぼすかについて詳細な検討はされていなかった.α を大きくするにつれ信号帯域幅が広くなるか ら,より大きな周波数ダイバーシチ効果が得られるとともに PAPR が低くなる.本論文では,周波数領域ルートナ イキストフィルタ送受信フィルタを用いる SC-FDE 信号伝送について,ロールオフファクタ αが PAPR および BER 特性に及ぼす影響を考察している. キーワード 周波数領域等化,周波数領域フィルタリング
2 citations
Additional excerpts
...最小二乗誤差 (MMSE)規範に基づく周 波数領域等化 (FDE)を用いればチャネルの周波数選択 性を利用して周波数ダイバーシチ効果を得ることがで き,BER 特性を大幅に改善できるという利点がある [6-8]....
[...]
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