| (Continuation of Questions 8/16 and 14/16) Motivation
This Question is responsible for all aspects of voiceband modem, facsimile terminal and voiceband signal discrimination standardization. This includes the functionality and performance across different network types.
Voiceband signal discrimination is a means to discriminate speech, music, tones and other voice¬band signals, and is widely used in telecommunication networks for example to save bandwidth and obtain trunking efficiency in codecs, voice gateways, circuit multiplication equipment, voiceband terminal, or to ensure correct operation of echo control and other signal enhancement devices, etc.
Generic voiceband signal discrimination (VSD) is motivated by two problems. Historically, VSD algorithms have been developed separately for individual network elements and applications, and there are currently numerous VSD algorithms. However, they are based on different principles, which make it difficult to provide common performance enhancements across all VSDs.
Therefore it is beneficial to develop a generic voiceband signal discriminator, which can be applied across a range of applications. The benefits from a standardized generic VSD are:
- enhanced performance to deal with new types of in-band audio signals;
- reduced development time and cost for new equipment requiring voice signal discrimination, e.g. voice gateways, circuit multiplication equipment, echo control, signal enhancement devices, terminal adapters and IP-relay equipment.
With the emergence of packet-based networks and specifically voice over packet, the GSTN has expanded to include the advantages of these network types. The need to ensure the best performance transmission of voiceband modems and facsimile over both circuit and packet switched networks is a necessary requirement. Packet-based networks that are designed for voice require methods and procedures to allow end-point modems to interoperate with the same performance as expected from circuit switched networks. In this spirit, the Question has developed Recommendations ITU T V.150.1, V.151, V.152, T.37 and T.38, all of which support different aspects of the transport of either voiceband modem signals or facsimile over IP networks.
The Question is also responsible for all aspects of voiceband modem and facsimile terminal (such as specification, performance evaluation and interworking) standardization. This includes the functionality and performance of the terminals and the transport of the signals they generate across different network types.
The Question will attempt to work electronically where possible and to make full use of e-mail and conferencing facilities in an attempt to reduce its carbon footprint.
Study items
Study items to be considered include, but are not limited to:
- identification of applications (other than speech transmission) and definition of associated performance requirements for generic voiceband signal discrimination;
- definition of algorithm(s) suitable for generic voiceband signal discrimination meeting the applications and performance requirements;
- definition of the test conditions and evaluation procedures to be applied in selecting between candidate algorithms on the basis of objective and subjective performance, in conjunction with Study Group 12;
- selection and specification of procedures to be used in verifying the implementation of selected algorithm or algorithms;
- optimized techniques to support the transmission of voiceband modem and facsimile signals over packet switched networks (IP ones in particular), using media gateways (V.15x-series of Recommendations). Methods, protocols and procedures to ensure robust transport of voiceband modem and facsimile signals in peer to peer IP networks;
- compatibility and interaction with network equipment, such as CME, VED and echo control devices;
- interworking issues arising from the use of modems on various multimedia platforms;
- means for evaluating voiceband modem and facsimile terminal performance, including the specification of network models and test procedures;
- definition of new or amended capabilities and their implementation for Group 3 and/or Group 4 terminals:
- definition of service and new usage of facsimile;
- support for new image compression and colour schemes for facsimile;
- the study of methods and procedures for the enhancement of real-time facsimile transmission over NGN including:
- revisions to transport layer and call control protocols, operation over mobile packet networks, gateway and IAF functionality and secure transmission;
- study of hybrid GSTN/IP tandem networks upon facsimile transmission;
- the study of methods and procedures for the enhancement of store and forward facsimile transmission using Internet mail capabilities;
- maintenance of related Recommendations: ITU T F.162, F.163, F.170, F.171, F.182 bis, F.185, F.190, T.4-T.6, T.22-T.24, T.30-T.33, T.35, T.36-T.39, T.42, T.43, T.45, T.503, T.563, V.8, V.8 bis, V.17, V.21, V.22, V.22 bis, V.24, V.27, V.27 bis, V.27 ter, V.29, V.32, V.32 bis, V.34, V.42, V.42 bis, V.43, V.44, V.56 bis, V.56 ter, V.59, V.61, V.70, V.75, V.76, V.80, V.90-V.92, V.110, V.120, V.130, V.150.0, V.150.1, V.151-V.153, V.250-V.254;
- considerations on how to help measure and mitigate climate change.
Tasks
Tasks include, but are not limited to:
- develop terms of reference for GVSD algorithms for non-codec applications;
- assist ITU T Study Group 12 in developing new Recommendations on GVSD testing methodologies;
- solicit proposals and conduct selection test(s) for candidate algorithms to meet these terms of reference;
- develop new Recommendation(s) based on the outcome of the(se) selection test(s);
- development of enhancements to V-series Recommendations;
- develop new Recommendation for the transport of voiceband modem and facsimile modem signals between two IP networks that use different transport methods;
- coordinate the application and integration of ITU T V.150.1, V.151, V.152 and V.153 with other relevant Recommendations;
- development of new DTE-DCE interface-related Recommendations as well as the revision of existing ones, new control Recommendations as well as the update of ITU T V.80 and the V.250-series;
- development of new and improved data compression techniques for application on voiceband and IP networks;
- enhancement of ITU T T.38 on gateway functionality and security aspects.
An up-to-date status of work under this Question is found in the SG 16 work programme (http://itu.int/ITU-T/workprog/wp_search.aspx?sp=15&q=15/16).
Relationships - Recommendations
- ITU-T G.70x-series, G.710-series, G.720-series, G.760-series, G.799-series, G.160-series, P.800-series, Q.115-series
- ITU-T E.450-series, E.460, F.162, F.163, F.170, F.182 bis, F.185, H.225, H.323, H.245, H.248, I.366.2, I.741, T.6, T.22, T.23, T.24, T.31, T.32, T.33, T.35, T.36, T.39, T.66, T.400-series, T.80-series, T.800-series, X.3, X.38 and X.39s
- Questions
- 1/16, 2/16 and 3/16 on gateway access to IP networks
- 7/16 and 10/16 on speech and audio coding
- 16/16 and 18/16 on network signal processing and interactions
- Study groups
- ITU-T SG 2 to identify other potential user applications
- ITU-T SG 11 on signalling requirements and protocols
- ITU-T SG 12 on speech and audio quality evaluation of specified algorithms
- ITU-T SG 13 on network architecture and speech and audio coding in IMT
- ITU-T SG 15 on access network issues
- ITU-T SG 17 on DTE-DCE interface issues
- ITU- R SG 5 to ensure compatibility with mobile transmission system constraints
- Other bodies
- 3GPP, 3GPP2
- ETSI
- IETF
- TIA
- ISO/IEC JTC 1/SC 6
- ISO/IEC, CIE, ICC
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