&lt;title&gt;Multiplexing based on wavelet packets&lt;/title&gt;

Wu, Jiangfeng; Jin, Qu; Wong, K.M.

doi:10.1117/12.205399

Cited by 11 publications

(7 citation statements)

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“…Wavelet bases enjoy a very strong optimality property for general inverse problems in that their use can achieve accurate and parsimonious representation of the input signal and simultaneously diagonalize the channel [10]. In addition, wavelet and other orthogonal modulation schemes have been suggested as a means of attaining reliable communication over multiple access, fading, and ISI channels [43]- [45]. While such modulation schemes are not required for implementation of the ML receiver presented here, the receiver is naturally adapted to them.…”

Section: Introductionmentioning

confidence: 99%

A maximum likelihood digital receiver using coordinate ascent and the discrete wavelet transform

Sharfer

Hero²

1999

IEEE Trans. Signal Process.

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Abstract-In this paper, a maximum likelihood (ML) method is presented for joint estimation of amplitude, phase, time delay, and data symbols in a single-user direct-sequence spreadspectrum communication system. Since maximization of the likelihood function is analytically intractable, a novel coordinate ascent algorithm is used to obtain sequential updates of the data symbols and all unknown nuisance parameters. The novelty of the algorithm is due to the use of a multiresolution expansion of the received signal and the use of polynomial rooting in the complex plane in place of a line search over the signal delay parameter. The multiresolution structure of the algorithm is exploited to reduce sensitivity to impulsive noise via wavelet thresholding. Computer simulations of the single-user system show that the algorithm has fast convergence, and comparison with theoretical lower bounds establishes that the algorithm achieves nearly optimal error performance.Index Terms-Bit synchronization, carrier phase recovery, impulsive noise mitigation, sequence estimation, wireless communications.

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Section: Introductionmentioning

confidence: 99%

A maximum likelihood digital receiver using coordinate ascent and the discrete wavelet transform

Sharfer

Hero²

1999

IEEE Trans. Signal Process.

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“…Starting before 1994, probably motivated by the book by Daubechies [113] and papers such as [114] and other works that described the properties of wavelet packets, research was pursued on possible applications to topics in communications with such designations in titles of published papers as wavelet-packet-based multiple access communications [100], orthogonally multiplexed communications via wavelet packet basis [101,102] and wavelet packet division multiplexing [103,104].…”

Section: Concluding Discussionmentioning

confidence: 99%

“…3 [87]. Wavelet packetbased multiple access communication systems that have been investigated before the research reported in this paper have all been focused upon the design of wavelet packets to minimize error criteria, subject to appropriate design constraints [100][101][102][103][104]. Although these may yield useful designs for particular applications, they do not specifically target the problem of having sufficient out-of-channel attenuation to attenuate signals from other services, whose signals are not orthogonal to the signals generated by the wavelet packet tree.…”

Section: An Example System Configuration Using Filter Bank Trees As Mmentioning

confidence: 99%

“…The details of two designs for low-pass and high-pass quadrature mirror filter (QMF) pairs that can be used to construct QMF synthesis-analysis filter banks consisting of replications of these pairs have been described in [83]. The basic idea behind wavelet packet-based multiple access communications [100][101][102][103][104] is that orthogonal signal sets are generated by transmitting signals from the leaves of the wavelet packet tree [86,105], along orthogonal paths in the tree, to the input of the channel. A typical wavelet-packet tree in which the QMF pairs, with subscripts on the symbols for the filters at each level of the tree that are the same, is shown in Fig.…”

Section: An Example System Configuration Using Filter Bank Trees As Mmentioning

confidence: 99%

“…In [83][84][85][86][87][88][89][90][91][92][93]103,[107][108][109], starting with wavelet packet basis functions and developing filter banks of quadrature mirror filter (QMF) pairs to process the samples which are coordinates on these bases, and to provide required stop band attenuation for out-of-band rejection, multiplexer-demultiplexer pairs for multi-carrier, multi-user bandwidth-on-demand, spectrally efficient downstream communications were developed. The new and advantageous features of these filter bank pairs were first identified and set down in [91,92,97].…”

Section: Reasons For Using Linear Phase Filter Designsmentioning

confidence: 99%

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Designs and architectures of filter bank trees for spectrally efficient multi-user communications: review, modifications and extensions of wavelet packet filter bank trees

Sablatash¹

2007

SIViP

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A review is presented first of the evolution of transmultiplexers since about 1966, in the context of a long progression of theoretical advances and developments leading to recent proposals to fundamentally improve OFDM type systems using principles of perfect reconstruction filter (PRF) banks. The equivalence of transmultiplexers to OFDM type multi-user systems is discussed. The desirable goals for performance and implementation of transmultiplexers or multiband, multiuser communication systems that are addressed and met in this paper using filter bank trees are set down. Then modifications and extensions are presented of the designs and architectures of wavelet packet based synthesis and analysis pairs of filter bank trees (Sablatash and Lodge in Digital Signal Process 13: 58-92, 2003) that can be used as transmultiplexers. These exhibit a number of advantages over the previous designs and address three shortcomings of the designs used to illustrate basic principles in Sablatash and Lodge (Digital Signal Process 13:58-92, 2003). The first of these is the asymmetry of the magnitude frequency responses of the multiplexer channels, which is addressed using a symmetric design for a lowpass and highpass quadrature mirror filter (QMF) pair described herein. The second is the problem of minimizing the total delay of the signal in passing through the analysis and synthesis filter banks. This is addressed using an architecture involving DFT polyphase synthesis filter banks to replace the wideband VSB filters at the roots of the two identical synthesis filter bank trees, but results in the multiplexer having fewer levels. In this way a Financial support under Industry Canada's Spectrum Research Funding is gratefully acknowledged.M. Sablatash (tradeoff is effected of lower delay and complexity with fewer levels of bandwidth on demand. At the receiver matching DFT polyphase analysis filters and the other matching analysis filters are implemented. The third shortcoming is the difficulty in designing a synchronization scheme if the filters in the synthesis and analysis filter banks have non-linear phase. This is addressed by designing linear phase filters that do not affect the ISI to any significant degree for communication purposes, although exact perfect reconstruction is lost, but greatly ease and improve the design of the synchronization scheme. Relationships of this paper and its advantages over recent research studies and IEEE 802.22 standards proposals using PR filter banks for multi-user systems to greatly improve on OFDM systems are discussed.

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Performance of wavelet packet division multiplexing in timing errors and flat fading channels

Wong

Jin

1996

Proceedings IWISP '96

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<title>Multiplexing based on wavelet packets</title>

Cited by 11 publications

References 0 publications

A maximum likelihood digital receiver using coordinate ascent and the discrete wavelet transform

A maximum likelihood digital receiver using coordinate ascent and the discrete wavelet transform

Designs and architectures of filter bank trees for spectrally efficient multi-user communications: review, modifications and extensions of wavelet packet filter bank trees

Performance of wavelet packet division multiplexing in timing errors and flat fading channels

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