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ITU-T Study Group 16 (Study Period 2005-2008) |
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Question 16/16 - Speech enhancement in signal processing network equipment |
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(Continuation of Question 6/15)
- Motivation
This Question deals with network-based speech enhancement devices, including electrical network echo control, acoustic
network echo control, automatic level control devices, and speech enhancement devices for wireless networks.
The application of echo cancellers continues to evolve in existing General Switched Telephone Networks (GSTN), cellular,
ATM and emerging IP networks. These applications bring new issues to echo canceller performance, and will require study
to ensure that network operators have adequate assurance of transmission quality from echo cancellers complying with G.168.
These issues may result in adding and improving the tests within G.168, and studying the issues arising from the deployment
of echo cancellers to ATM and IP networks and new services within the GSTN.
There is also a need to address equipment-related issues associated with echo cancellers such as defining appropriate
interfaces of echo cancellers, alarming requirements, power requirements, and the possible integration of automatic
level control and other speech enhancement functions into echo cancellers.
With the deployment of Automatic Level Control (ALC) and Voice Enhancement Devices (VEDs), new issues are expected to
arise as these devices are applied to existing and emerging networks. As a result, Recommendation G.169 may need to be
revised and work on new Recommendation G.160 (VED) needs to continue to ensure adequate transmission quality.
The following major Recommendations, in force at the time of approval of this Question, fall under its responsibility:
G.164, G.165, G.168, G.169.
- Study Items
Study items to be considered include, but are not limited to:
- What functional characteristics and requirements are necessary for network-based speech enhancement devices to provide good performance in existing GSTN and emerging ATM/IP and cellular networks?
- What requirements are necessary for the equipment-related aspects of network-based speech enhancement devices?
- What management interfaces should be recommended for speech enhancement equipment?
- What tests and requirements are necessary to ensure good performance of speech enhancement devices and how can they be enhanced to better correlate with subjective test results?
- What is the performance of speech enhancement devices in GSTN, ATM/IP, cellular and other wireless environments with facsimile and voice-band data signals, text telephones, signalling tones, call-processing tones, speech, etc?
- What hardware and software tools are necessary to support the testing of speech enhancement devices?
- What realistic echo paths and test signals are required for testing speech enhancement devices?
- How should in-path speech enhancement equipment be designed so as not to interfere with tandem codec avoidance mechanisms (e.g. vocoder bypass or tandem-free operation)?
- What are the requirements of speech enhancement devices to minimise any degradations in performance due to tandeming?
- Tasks
Tasks include, but are not limited to:
- Revise Recommendations G.168 and G.169 as necessary
- Continue development of new Recommendation G.160 on Voice Enhancement Devices
- Develop draft new Recommendation(s) on equipment aspects of speech enhancement devices
- Develop draft new Recommendation(s) on acoustic network echo controllers not associated with wireless networks
- Develop guidelines for the application of speech enhancement devices to be included in the respective Recommendations above
An up-to-date status of work under this Question is contained in the
SG 16 Work Programme.
- Relationships
Recommendations:
- G.161, G.108.2, P.501, P.502, P.340, Q.115.1
Questions:
- Q.11/16, Q.14/16, Q.16/16, Q.17/16, Q.18/16
Other Study Groups:
- ITU-T SG 4 on Telecommunications Management Network (TMN) aspects
- ITU-T SG 11 on signalling issues
- ITU-T SG 12 on application guidelines and subjective performance
- ITU-T SG 13 on ATM and IP issues
- ITU-R SG 4 WP4B on voice on mixed terrestrial/satellite networks
Other bodies:
- ATM Forum on ATM issues
- IETF working groups AVT and IPTEL on IP transport
- ETSI and TIA on tandem-free operation
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