Question 14/12 - In-service non-intrusive assessment of voice transmission performance
(Continuation of Question 16/12)
Motivation
Signal processing technology applied to both directions of transmission in a 4-wire path, can be used to estimate the contribution of a number of factors affecting the transmission performance of the complete connection, without interfering with the signals on the connection;
Desirable voice service measurements can be found in ITU-T Recommendation P.561, and guidance for the analysis and the interpretation of the measurement results can be found in ITU-T Recommendation P.562.
A device that performs such measurements is known as an In-service Non-intrusive Measurement Device (INMD).
Time Division Multiplexing (TDM) systems are covered by INMD of classes A, B and C.
As far as packetized systems (and more generally, non linear systems) are concerned, they are currently covered by Class D devices since the last update of existing Recommendations (P.561 and P.562) on INMDs to take into consideration new systems like IP network equipments.
The work on a new recommendation defining a standard model for the assessment of voice transmission quality from protocol analysis information in IP networks (known currently as P.VTQ), started during study period 2001-2004.
The following Recommendations, in force at the time of approval of this Question, fall under its responsibility:
P.56, P.561, P.562
Question
Study items to be considered include, but are not limited to:
- What changes and/or improvements can be made to ITU-T Recommendations P.561 and P.562?
- How can non-intrusive measurements at the IP layers be implemented and improved, for instance by taking into account new protocols (e.g. RTCP
XR)?
- What relationship exists between the subjective responses of users at the terminals and the objective measurements made from the point at which the non-intrusive assessment system is connected ?
- What measures give an estimate of the transmission quality of a connection including the accumulated effects of all technologies (e.g. IP, wireless, ATM, etc.)?
- How can such measures be used to assess, plan and maintain the transmission quality of networks?
- How are non-intrusive measurements related to intrusive measurements?
- What new standards are needed to address non-intrusive evaluation of quality for other media than voice (video, multimedia)?
- How can talking quality and conversational quality be measured in a non-intrusive way?
Tasks
Tasks include, but are not limited to:
- Updating of Recommendation P.561 (if needed)
- Updating of Recommendation P.562 (if needed, separately or following changes in P.561)
- New Recommendation on derivation of voice transmission quality from non-intrusive IP protocol analysis
(P.VTQ)
- New Recommendation on non-intrusive measurement of speech quality including audio parameters
- New Recommendation on non-intrusive evaluation of multimedia quality
Relationships
Recommendations: G.107, G.115, G.131, P.56, P.561, P.562, P.563
Questions: 8/12, 9/12
Other study groups: SG 2, SG 9, SG13
Standardisation bodies: ETSI (STQ, TISPAN), IETF (IPPM, AVT).
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