|
(Continuation of Question 7/12 studied in 1997-2000)
Type of question
Task oriented, leading to updated Recommendation P.501, P.502 and new
Recommendation P.OQN (objective quality number).
Background
Terminal and network equipment increasingly includes complex signal
processing techniques, wideband systems are entering the market place. Such
devices can no longer be regarded as linear, time-invariant systems. The
subjectively relevant transmission characteristics of such equipment
needs to be correctly determined using adequate measurement methods.
There is a need of having reproducible, well defined measurement methods
available -for certification laboratories as well as for developers which
ideally should be combined to one quality value.
During Study Period 1997-2000 test signals and analysis techniques for
use in telephonometry have been collected. This work led to Recommendations
P.501 and P.502. Test signals and analysis techniques allow to evaluate many
different parameters but still some are missing (e.g. assessment of
background noise) and it is very likely that new signal processing methods
show up which can not be covered adequately by the existing signals and
methods. In addition the interaction of signal processing at various
locations of a connection needs to be investigated more in detail.
Text of the question
considering
a) that increasingly complex signal processing is used in terminals and
networks which may influence each other;
b) wideband transmission systems are about to enter the market place;
c) terminals are used in more complex acoustical and noisy environments;
d) VAD, comfort noise injection and other techniques may influence the
transmission especially of background noise quite significantly;
e) many single objective numbers determining individual quality
parameters are available, but no quality parameter describing the speech
quality for complex signal processing systems in the conversational
situation is available,
the following questions should be studied:
1) How can the existing test methods and test signals be applied to
complex end to end transmission scenarios including terminals?
2) Are additional or new test methods or signals required for testing
end to end transmission including the conversational situation?
3) In what way can individual objective quality parameters be
combined to an overall quality value specifically for terminals?
4) What methods are suitable for the objective assessment of
background noise transmission and to what extent can the background
noise transmission be assessed without making reference to the
background noise signal?
Objectives and schedule
Revision of relevant P-Series Recommendations P.501, P.502 and creation
of a new P-Series Recommendation P.OQN (objective quality number), will be
completed within the Study Period.
Relationship with other Recommendations, Questions, Study Groups:
- Recommendations: P.340, P.341, P.310, P.79, G.168, G.169.
- Questions: 4, 5, 8 and 9/12.
- Study Groups: SG 15.
- Other Standards Bodies: ETSI STQ, TIPHON, TIA, IEEE
|
