(Continuation and extension of Question 15/12 studied in 1997-2000)
Type
Task-oriented, leading to new and revised ITU-T Recommendations.
Background
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).
As far as packetized systems (and more generally, non linear systems) are
concerned, they are theoretically covered in P.561 by class D devices. The
section of P.561 on those devices was left for further study during the last
study period. New documentation and study results, as well as the evolution
of network technologies (including interworking between, circuit switched,
and packet switched mobile of fix networks), show that the time has come to
think of an update of existing Recommendations on INMDs to take into
consideration new systems like IP network equipments.
The parameters that can be added to existing INMD parameters include:
- non linear distortion,
- packet protocol parameters like latency, jitter and packet loss.
Text of the Question
1 What changes and/or improvements can be made to ITU-T
Recommendations P.561 and P.562 to take into consideration new impairments
generated in non-linear systems and how can measurements be made at the IP
as well as other layers?
2 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 ?
3 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.)?
4 How can such measures be used to assess, plan and maintain the
transmission quality of networks ?
5 How are non-intrusive measurements related to conventional
intrusive measurements ?
Objectives and Schedule
Revised Recommendation P.561 by 2002 and P.562 by 2003.
New draft Recommendation on non-intrusive measurement of speech quality
including audio parameters by 2004.
Relationship with other Study Groups and Questions
Liaison should be maintained with ITU-T Study Group 2 who deal with
Quality of Service (QoS), ITU-T Study Group 4 whose responsibility is
maintenance of networks, and ITU-T Study Group 13 which is the leading study
group for internet protocol topics.
The work under other standardisation bodies, like ETSI (STQ, TIPHON) or
IETF (IPPM), can also be useful for this new question.
The studies of Q.16 will also be fed by results coming from Q. 8, 9 (WP2)
and 12 (WP3) of SG 12.
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