Hybrid FIR-IIR Adaptive Echo Canceller for Wireline Applications

Author

Shalash, Ahmed F.

Author_Institution

New Jersey Design Center, Analog Devices Inc., Somerset, NJ

fYear

2005

fDate

Oct. 28 2005-Nov. 1 2005

Firstpage

364

Lastpage

368

Abstract

In wireline communications, echo is a problem affecting analog front-end dynamic range and received signal to noise ratio. Echo cancellation schemes were devised using adaptive filtering but they are computationally expensive. Traditionally, echo cancellers are implemented using adaptive FIR filters that tend to be long to allow for enough echo rejection. In this paper a new equation-error based IIR-tail connected in tandem with FIR echo canceller is introduced. The new architecture can save up to 50% of the number of FIR taps needed for the echo cancellation. Simplified weight update for the new architecture is examined using block-update LMS for the FIR portion and full update for the IIR portion. The combined savings can be up to 70% compared to regular FIR only adaptive echo canceller. Echo rejection performance is verified via simulations and adaptive IIR stability is confirmed for the equation-error based adaptation

Keywords

FIR filters; IIR filters; adaptive filters; echo suppression; filtering theory; least mean squares methods; radio networks; adaptive filtering; analog front-end dynamic range; block-update LMS; echo rejection; equation-error based IIR-tail; hybrid FIR-IIR adaptive echo canceller; signal to noise ratio; wireline communications; Adaptive filters; Computer architecture; Echo cancellers; Equations; Finite impulse response filter; IIR filters; Least squares approximation; Stability; Tail; Topology;

fLanguage

English

Publisher

ieee

Conference_Titel

Signals, Systems and Computers, 2005. Conference Record of the Thirty-Ninth Asilomar Conference on

Conference_Location

Pacific Grove, CA

ISSN

1058-6393

Print_ISBN

1-4244-0131-3

Type

conf

DOI

10.1109/ACSSC.2005.1599769

Filename

1599769