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Journal ArticleDOI

Channel equalization in filter bank based multicarrier modulation for wireless communications

01 Jan 2007-EURASIP Journal on Advances in Signal Processing (Springer International Publishing)-Vol. 2007, Iss: 1, pp 140-140
TL;DR: Channel equalization in filter bank based multicarrier (FBMC) modulation is addressed and a novel structure, consisting of a linear-phase FIR amplitude equalizer and an allpass filter as phase equalizer is found to provide enhanced robustness to timing estimation errors.
Abstract: Channel equalization in filter bank based multicarrier (FBMC) modulation is addressed. We utilize an efficient oversampled filter bank concept with 2x-oversampled subcarrier signals that can be equalized independently of each other. Due to Nyquist pulse shaping, consecutive symbol waveforms overlap in time, which calls for special means for equalization. Two alternative linear low-complexity subcarrier equalizer structures are developed together with straightforward channel estimation-based methods to calculate the equalizer coefficients using pointwise equalization within each subband (in a frequency-sampled manner). A novel structure, consisting of a linear-phase FIR amplitude equalizer and an allpass filter as phase equalizer, is found to provide enhanced robustness to timing estimation errors. This allows the receiver to be operated without time synchronization before the filter bank. The coded error-rate performance of FBMC with the studied equalization scheme is compared to a cyclic prefix OFDM reference in wireless mobile channel conditions, taking into account issues like spectral regrowth with practical nonlinear transmitters and sensitivity to frequency offsets. It is further emphasized that FBMC provides flexible means for high-quality frequency selective filtering in the receiver to suppress strong interfering spectral components within or close to the used frequency band.

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Citations
More filters
Journal ArticleDOI
TL;DR: In this article, the authors present a unified review of waveform design options for multicarrier schemes, and pave the way for the evolution of the multic-carrier schemes from the current state of the art to future technologies.
Abstract: Due to their numerous advantages, communications over multicarrier schemes constitute an appealing approach for broadband wireless systems. Especially, the strong penetration of orthogonal frequency division multiplexing (OFDM) into the communications standards has triggered heavy investigation on multicarrier systems, leading to re-consideration of different approaches as an alternative to OFDM. The goal of the present survey is not only to provide a unified review of waveform design options for multicarrier schemes, but also to pave the way for the evolution of the multicarrier schemes from the current state of the art to future technologies. In particular, a generalized framework on multicarrier schemes is presented, based on what to transmit, i.e., symbols, how to transmit, i.e., filters, and where/when to transmit, i.e., lattice. Capitalizing on this framework, different variations of orthogonal, bi-orthogonal, and non-orthogonal multicarrier schemes are discussed. In addition, filter designs for various multicarrier systems are reviewed considering four different design perspectives: energy concentration, rapid decay, spectrum nulling, and channel/hardware characteristics. Subsequently, evaluation tools which may be used to compare different filters in multicarrier schemes are studied. Finally, multicarrier schemes are evaluated from the perspective of practical implementation aspects, such as lattice adaptation, equalization, synchronization, multiple antennas, and hardware impairments.

316 citations

Posted Content
TL;DR: The goal of the present survey is to provide a unified review of waveform design options for multicarrier schemes to pave the way for the evolution of the multicarriers schemes from the current state of the art to future technologies.
Abstract: Due to their numerous advantages, communications over multicarrier schemes constitute an appealing approach for broadband wireless systems. Especially, the strong penetration of orthogonal frequency division multiplexing (OFDM) into the communications standards has triggered heavy investigation on multicarrier systems, leading to re-consideration of different approaches as an alternative to OFDM. The goal of the present survey is not only to provide a unified review of waveform design options for multicarrier schemes, but also to pave the way for the evolution of the multicarrier schemes from the current state of the art to future technologies. In particular, a generalized framework on multicarrier schemes is presented, based on what to transmit, i.e., symbols, how to transmit, i.e., filters, and where/when to transmit, i.e., lattice. Capitalizing on this framework, different variations of orthogonal, bi-orthogonal, and nonorthogonal multicarrier schemes are discussed. In addition, filter design for various multicarrier systems is reviewed considering four different design perspectives: energy concentration, rapid decay, spectrum nulling, and channel/hardware characteristics. Subsequently, evaluation tools which may be used to compare different filters in multicarrier schemes are studied. Finally, multicarrier schemes are evaluated from the view of the practical implementation issues, such as lattice adaptation, equalization, synchronization, multiple antennas, and hardware impairments.

291 citations


Cites methods from "Channel equalization in filter bank..."

  • ...In [107] and [108], equalization methods for this approach are introduced under three categories:...

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  • ...PAPR [53], [107], [138], [139] [139] [53], [138] [140] [96]...

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  • ...Equalization [52], [54], [55], [61], [106]–[108], [110], [112]– [115], [121] [167] [39], [40], [45], [46], [50], [51], [106], [107], [109], [110], [113]–[115], [123] [108], [111], [112], [121], [157], [168] [134], [165] [51], [106] [16], [21], [22], [93], [94] [74] [47]...

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  • ...Time & Frequency Synchronization [1], [28], [84], [89], [116]–[118] [27] [28], [84], [107], [117], [118], [123]– [126] [89], [108], [116], [120]– [122] [117] [117], [119] [28], [84] [117]...

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  • ...• The second approach utilizes equalization filters at the receiver for each subcarrier, which operates at the symbol rate [39], [107]....

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Journal ArticleDOI
TL;DR: The results obtained confirm the effectiveness of the proposed technique with channels that exhibit significant frequency selectivity at the subchannel level and show a performance comparable with the optimum minimum mean-square-error equalizer, despite a significantly lower computational complexity.
Abstract: In this paper, the problem of channel equalization in filter bank multicarrier (FBMC) transmission based on the offset quadrature-amplitude modulation (OQAM) subcarrier modulation is addressed. Finite impulse response (FIR) per-subchannel equalizers are derived based on the frequency sampling (FS) approach, both for the single-input multiple-output (SIMO) receive diversity and the multiple-input multiple-output (MIMO) spatially multiplexed FBMC/OQAM systems. The FS design consists of computing the equalizer in the frequency domain at a number of frequency points within a subchannel bandwidth, and based on this, the coefficients of subcarrier-wise equalizers are derived. We evaluate the error rate performance and computational complexity of the proposed scheme for both antenna configurations and compare them with the SIMO/MIMO OFDM equalizers. The results obtained confirm the effectiveness of the proposed technique with channels that exhibit significant frequency selectivity at the subchannel level and show a performance comparable with the optimum minimum mean-square-error equalizer, despite a significantly lower computational complexity. The possibility of tolerating significant subchannel frequency selectivity gives more freedom in the multicarrier system parameterization. For example, it is possible to use significantly wider subcarrier spacing than what is feasible in OFDM, thus relieving various critical design constraints.

136 citations


Cites methods from "Channel equalization in filter bank..."

  • ...In [22], the FS-based per-subchannel equalizer design was introduced in the context of single-antenna transmission for...

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  • ...In this paper, we extend the frequency sampling (FS)-based equalizer design technique, which is originally introduced in [29] and thoroughly analyzed in [22], for the per-subchannel equalization in multi-antenna FBMC/OQAM receivers....

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  • ...resulting in notable performance gain, as demonstrated in [22] in the SISO case....

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  • ...The core idea of this technique is to set the equalizer coefficients such that the frequency response of the designed equalizer is forced to take given target values at a set of chosen frequency points within a subchannel bandwidth [22]....

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  • ...The zero-ISI and zero-ICI conditions are discussed in the SISO case in [22], with analytic formulas for residual subchannel ISI and ICI....

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Journal ArticleDOI
TL;DR: By applying pilots designed specifically for filter banks, the carrier frequency offset, fractional time delay, and channel response can be accurately estimated and a novel joint FTD and channel estimation scheme permits extending the FTD estimation range well beyond the limit imposed by the pilot separation.
Abstract: This paper presents a detailed analysis of synchronization methods based on scattered pilots for filter bank based multicarrier (FBMC) communications, taking into account the interplay of the synchronization, channel estimation, and equalization methods. We show that by applying pilots designed specifically for filter banks, the carrier frequency offset (CFO), fractional time delay (FTD), and channel response can be accurately estimated. Further, a novel joint FTD and channel estimation scheme, based on iterative interference cancelation, permits extending the FTD estimation range well beyond the limit imposed by the pilot separation. The channel parameter estimation and compensation are successfully performed totally in the frequency domain, in a subchannel-wise fashion, which is appealing in spectrally agile and cognitive radio scenarios. The performance evaluation is done in a hypothetical WiMAX scenario in which an FBMC system would substitute OFDM maintaining as much physical layer compatibility as possible.

114 citations


Cites background or methods from "Channel equalization in filter bank..."

  • ...The authors of this paper have worked on a lowcomplexity, subcarrier-wise FBMC equalizer using oversampled subcarrier signals [39, 40]....

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  • ...Taking into account these assumptions, the equalizer coefficients can readily be derived from the target values in (9) above as [39]...

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Journal ArticleDOI
TL;DR: A new joint symbol timing and CFO synchronization algorithm is proposed based on the least squares approach and exploiting the transmission of a training sequence made up of identical parts, compared with two data-aided synchronization algorithms previously proposed in the literature.
Abstract: In this paper we consider the problem of data-aided joint symbol timing and carrier-frequency offset (CFO) estimation for filter bank-based multicarrier (FBMC) systems. As all multicarrier systems, FBMC systems are very sensitive to synchronization errors, since CFO and symbol timing errors cause interference between successive symbols and adjacent subcarriers which can lead to a severe performance degradation. Therefore, reliable and accurate synchronization algorithms must be designed for these systems. The approach herein presented is based on the deployment of appropriate training sequences. In particular, we propose a new joint symbol timing and CFO synchronization algorithm based on the least squares approach and exploiting the transmission of a training sequence made up of identical parts. The performance of the derived estimators, assessed by computer simulations, is compared with that of two data-aided synchronization algorithms previously proposed in the literature.

113 citations


Cites background from "Channel equalization in filter bank..."

  • ...FBMC systems referred to as Filtered Multitone (FMT) systems have been proposed for very high-speed digital subscriber line (VDSL) standards [1] and are under investigation also for broadband wireless applications [2], [3]....

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References
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TL;DR: A simple but nonoptimum decoding scheme operating directly from the channel a posteriori probabilities is described and the probability of error using this decoder on a binary symmetric channel is shown to decrease at least exponentially with a root of the block length.
Abstract: A low-density parity-check code is a code specified by a parity-check matrix with the following properties: each column contains a small fixed number j \geq 3 of l's and each row contains a small fixed number k > j of l's. The typical minimum distance of these codes increases linearly with block length for a fixed rate and fixed j . When used with maximum likelihood decoding on a sufficiently quiet binary-input symmetric channel, the typical probability of decoding error decreases exponentially with block length for a fixed rate and fixed j . A simple but nonoptimum decoding scheme operating directly from the channel a posteriori probabilities is described. Both the equipment complexity and the data-handling capacity in bits per second of this decoder increase approximately linearly with block length. For j > 3 and a sufficiently low rate, the probability of error using this decoder on a binary symmetric channel is shown to decrease at least exponentially with a root of the block length. Some experimental results show that the actual probability of decoding error is much smaller than this theoretical bound.

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01 Nov 1985
TL;DR: This month's guest columnist, Steve Bible, N7HPR, is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California, and his research area closely follows his interest in amateur radio.
Abstract: Spread Spectrum It’s not just for breakfast anymore! Don't blame me, the title is the work of this month's guest columnist, Steve Bible, N7HPR (n7hpr@tapr.org). While cruising the net recently, I noticed a sudden bump in the number of times Spread Spectrum (SS) techniques were mentioned in the amateur digital areas. While QEX has discussed SS in the past, we haven't touched on it in this forum. Steve was a frequent cogent contributor, so I asked him to give us some background. Steve enlisted in the Navy in 1977 and became a Data Systems Technician, a repairman of shipboard computer systems. In 1985 he was accepted into the Navy’s Enlisted Commissioning Program and attended the University of Utah where he studied computer science. Upon graduation in 1988 he was commissioned an Ensign and entered Nuclear Power School. His subsequent assignment was onboard the USS Georgia, a trident submarine stationed in Bangor, Washington. Today Steve is a Lieutenant and he is completing a master’s degree in computer science at the Naval Postgraduate School in Monterey, California. His areas of interest are digital communications, amateur satellites, VHF/UHF contesting, and QRP. His research area closely follows his interest in amateur radio. His thesis topic is Multihop Packet Radio Routing Protocol Using Dynamic Power Control. Steve is also the AMSAT Area Coordinator for the Monterey Bay area. Here's Steve, I'll have some additional comments at the end.

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TL;DR: In this paper, a review of Discrete-Time Multi-Input Multi-Output (DIMO) and Linear Phase Perfect Reconstruction (QLP) QMF banks is presented.
Abstract: 1. Introduction 2. Review of Discrete-Time Systems 3. Review of Digital Filters 4. Fundamentals of Multirate Systems 5. Maximally Decimated Filter Banks 6. Paraunitary Perfect Reconstruction Filter Banks 7. Linear Phase Perfect Reconstruction QMF Banks 8. Cosine Modulated Filter Banks 9. Finite Word Length Effects 10. Multirate Filter Bank Theory and Related Topics 11. The Wavelet Transform and Relation to Multirate Filter Banks 12. Multidimensional Multirate Systems 13. Review of Discrete-Time Multi-Input Multi-Output LTI Systems 14. Paraunitary and Lossless Systems Appendices Bibliography Index

4,757 citations

Book
31 Dec 1999
TL;DR: In this paper, the authors present a comprehensive introduction to OFDM for wireless broadband multimedia communications and provide design guidelines to maximize the benefits of this important new technology, including modulation and coding, synchronization, and channel estimation.
Abstract: From the Book: The manifestations of the mode of goodness can be experienced when all the gates of the body are illuminated by knowledge The Bhagavad Gita (14.11) During the joint supervision of a Master's thesis "The Peak-to-Average Power Ratio of OFDM," of Arnout de Wild from Delft University of Technology, The Netherlands, we realized that there was a shortage of technical information on orthogonal frequency division multiplexing (OFDM) in a single reference. Therefore, we decided to write a comprehensive introduction to OFDM. This is the first book to give a broad treatment to OFDM for mobile multimedia communications. Until now, no such book was available in the market. We have attempted to fill this gap in the literature. Currently, OFDM is of great interest by the researchers in the Universities and research laboratories all over the world. OFDM has already been accepted for the new wireless local area network standards from IEEE 802.11, High Performance Local Area Network type 2 (HIPERLAN/2) and Mobile Multimedia Access Communication (MMAC) Systems. Also, it is expected to be used for the wireless broadband multimedia communications. OFDM for Wireless Multimedia Communications is the first book to take a comprehensive look at OFDM, providing the design guidelines one needs to maximize benefits from this important new technology. The book gives engineers a solid base for assessing the performance of wireless OFDM systems. It describes the new OFDM-based wireless LAN standards; examines the basics of direct-sequence and frequency-hopping CDMA, helpful in understanding combinations of OFDM and CDMA. It also looks at applications of OFDM, includingdigital audio and video broadcasting, and wireless ATM. Loaded with essential figures and equations, it is a must-have for practicing communications engineers, researchers, academics, and students of communications technology. Chapter 1 presents a general introduction to wireless broadband multimedia communication systems (WBMCS), multipath propagation, and the history of OFDM. A part of this chapter is based on the contributions of Luis Correia from the Technical University of Lisbon, Portugal, Anand Raghawa Prasad from Lucent Technologies, and Hiroshi Harada from the Communications Research Laboratory, Ministry of Posts and Telecommunications, Yokosuka, Japan. Chapters 2 to 5 deal with the basic knowledge of OFDM including modulation and coding, synchronization, and channel estimation, that every post-graduate student as well as practicing engineers must learn. Chapter 2 contains contributions of Rob Kopmeiners from Lucent Technologies on the FFT design. Chapter 6 describes the peak-to-average power problem, as well as several solutions to it. It is partly based on the contribution of Arnout de Wild. Basic principles of CDMA are discussed in Chapter 7 to understand multi carrier CDMA and frequency-hopping OFDMA, which are described in Chapters 8 and 9. Chapter 8 is based on the research contributions from Shinsuke Hara from the University of Osaka, Japan, a postdoctoral student at Delft University of Technology during 1995-96, Chapter 9 is based on a UMTS proposal, with main contributions of Ralf Bohnke from Sony, Germany, David Bhatoolaul and Magnus Sandell from Lucent Technologies, Matthias Wahlquist from Telia Research, Sweden, and Jan-Jaap van de Beek from Lulea University, Sweden. Chapter 10 was written from the viewpoint of top technocrats from industries, government departments, and policy-making bodies. It describes several applications of OFDM, with the main focus on wireless ATM in the Magic WAND project, and the new wireless LAN standards for the 5 GHz band from IEEE 802.11, HIPERLAN/2 and MMAC. It is partly based on contributions from Geert Awater from Lucent Technologies, and Masahiro Morikura and Hitoshi Takanashi from NTT in Japan and California, respectively. We have tried our best to make each chapter quite complete in itself This book will help generate many new research problems and solutions for future mobile multimedia communications. We cannot claim that this book is errorless. Any remarks to improve the text and correct any errors would be highly appreciated.

4,020 citations


"Channel equalization in filter bank..." refers background in this paper

  • ...Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007, Article ID 49389, 18 pages doi:10.1155/2007/49389 Research Article Channel Equalization in Filter Bank Based Multicarrier Modulation for Wireless Communications Tero Ihalainen,1 Tobias Hidalgo Stitz,1 Mika…...

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