Echo control in VoIP

Authors

  • Samy El-Hennawey Nortel - Enterprise Solutions, Belleville, Ont. K8N 5M1, Canada

Keywords:

Feedback control, Gateways (computer networks), Internet protocols, Microphones, Telecommunication systems, Echo canceller, Echo control, Voice over the Internet Protocol

Abstract

The challenges faced in echo control in voice over the Internet Protocol (VoIP) are discussed. There are primarily two classes of echo in telephone conversation. The first class is due to the use of a 2-to-4 wire conversion using hybrid circuits. Echo control of this class is achieved by a line echo canceller (LEC). The other class is due to the use of handsfree mechanisms where there is significant acoustical feedback coupling between the receiver speaker and the receiver microphone. Echo control of this class is achieved using an acoustic echo canceller (AEC). The design of double-talk detectors is a challenge for VoIP gateway design. Another challenge seen in deploying VoIP with voice gateways to interface with PSTN is that some PSTN local loops have strange characteristics. It is highly desirable to measure echo at the end user of an IP phone with multi-vendor networks. An important impairment, that is to be measured, is echo with its echo path loss and its associated round-trip delay.

Additional Files

Published

2007-09-01

How to Cite

1.
El-Hennawey S. Echo control in VoIP. Canadian Acoustics [Internet]. 2007 Sep. 1 [cited 2026 May 10];35(3):88-9. Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/1914

Issue

Vol. 35 No. 3 (2007)

Section

Proceedings of the Acoustics Week in Canada

License

Author Licensing Addendum

This Licensing Addendum ("Addendum") is entered into between the undersigned Author(s) and Canadian Acoustics journal published by the Canadian Acoustical Association (hereinafter referred to as the "Publisher"). The Author(s) and the Publisher agree as follows:

  1. Retained Rights: The Author(s) retain(s) the following rights:

    • The right to reproduce, distribute, and publicly display the Work on the Author's personal website or the website of the Author's institution.
    • The right to use the Work in the Author's teaching activities and presentations.
    • The right to include the Work in a compilation for the Author's personal use, not for sale.

  2. Grant of License: The Author(s) grant(s) to the Publisher a worldwide exclusive license to publish, reproduce, distribute, and display the Work in Canadian Acoustics and any other formats and media deemed appropriate by the Publisher.

  3. Attribution: The Publisher agrees to include proper attribution to the Author(s) in all publications and reproductions of the Work.

  4. No Conflict: This Addendum is intended to be in harmony with, and not in conflict with, the terms and conditions of the original agreement entered into between the Author(s) and the Publisher.

  5. Copyright Clause: Copyright on articles is held by the Author(s). The corresponding Author has the right to grant on behalf of all Authors and does grant on behalf of all Authors, a worldwide exclusive license to the Publisher and its licensees in perpetuity, in all forms, formats, and media (whether known now or created in the future), including but not limited to the rights to publish, reproduce, distribute, display, store, translate, create adaptations, reprints, include within collections, and create summaries, extracts, and/or abstracts of the Contribution.