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

Abstract

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.

Quadrature mirror filter bank design based on hybrid bee colony technique

“…In signal processing systems, QMF bank provides number of advantages such as removal of aliasing distortion, wider bandwidth and lower bit rates without degrading quality of output signal. Because of these advantages, QMF bank is used in multi-tone modulation systems [1], sub band coding of speech [2], analog to digital conversion [3], image processing [4], multiplexers [5], twodimensional short time spectral analysis [6], design of wavelet bases [7,8], antenna system [9], biomedical signal processing [10], wireless communication for noise cancellation [11] and wide-band beam-forming for sonar [12].…”

Design of Alias-Free Linear Phase Quadrature Mirror Filter Banks using Eigen value-Eigen vector Approach

“…Finite-duration impulse response (FIR) QMF banks have been extensively used in many signal processing fields, such as automated methods for scoring tissue microarray spots [1], multi-user communication [2], image compression [3,4], trans-multiplexers used in FDM/TDM conversion [5], multi-tone modulation systems [6], ECG signal compression [7], antenna systems [8], audio industry [9], biomedical signal processing [10], sub-band coding of speech and image signals [11,12] and wideband beam forming for sonar [13]. Figure 1, shows the basic structure of a two-channel quadrature mirror filter bank.…”

Two-Channel Quadrature Mirror Filter Bank: An Overview

“…Eventually, at some point in the process, the subband signals are recombined so that the original signal is properly reconstructed [3]. These filters find applications in many signal processing fields, such as design of wavelet bases [4,5], image compression [6,7], digital transmultiplexers used in FDM/TDM conversion [8,9], discrete multitone modulation systems [10], ECG signal compression [11,12], antenna systems [13], digital audio industry [14], biomedical signal processing [15], equalization of wireless communication channels [16], and analog voice privacy systems [17], due to advancement in QMF bank.…”