Colombia, 23-24 September 2013 The importance of models and procedures for planning, monitoring and control in the provision of communications services Dr.-Ing. H. W. Gierlich Head of Telecom Division CITEL (PCC.I)/ ITU Forum on Information and Communication Technology Service: Quality, Control and Surveillance (Cartagena de Indias, Colombia, 23-24 September 2013)
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La importancia de los modelos y procedimientos para la planificación, seguimiento y control en la prestación de servicios de comunicación
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Colombia, 23-24 September 2013
The importance of models and procedures for planning, monitoring and control in the
provision of communications services
Dr.-Ing. H. W. Gierlich
Head of Telecom Division
CITEL (PCC.I)/ ITU Forum on Information and
Communication Technology Service:
Quality, Control and Surveillance
(Cartagena de Indias, Colombia, 23-24 September 2013)
Colombia, 23-24 September 2013 2
Outline
Introduction
Communication Services –Underlying System configurations
Planning: The ITU-T E-model (G.107 & G.108)
Network Monitoring: P.862, P.863 & P.563
Wideband – The new Challenge
Summary
ITU-T: QoS and QoE
Quality of Service (QoS):
Totality of characteristics of a telecommunications service that bear on its ability to satisfy stated and implied needs of the user of the service.
Quality of Experience (QoE):
The overall acceptability of an application or service, as perceived subjectively by the end-user.Quality of experience includes the complete end-to-end system effects (client, terminal, network, services infrastructure, etc.).
Overall acceptability may be influenced by user expectations and context.
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Speech Quality –what we would like to have
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1m
“orthotelefonic reference position”
Speech Quality…
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speechquality
talkingsituation
listeningsituation
conversationalsituation
… from the user’s perspective
End to End Conifguration
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ISCDSL ISC PBX GW
PSTN
1-15 ms240 ms
MSC BSS
90-120 ms
IP-GW
Netw. 1
IP-GW
10 - 400 ms10 - 400 ms
add. 1 - 100 ms !
Netw. 2
Impact on speech quality:- delay now time variant
- echo much more dominant
- Coding distortion
- background noise problems
- insufficient quality of the analog network components (att., noise, distortion…)
- insufficient quality of acoustical components
A big problem of today‘s networks, interconnection & terminals : delay – unpredictable, load
dependant, time variant
Contributions to Quality
The networks
Type of networks
Interconnection
QoS management
The endpoints
Types of terminals
Interoperability
Terminal – Network
Terminal – Terminal
The users‘ location
Environmental conditions
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• Network planning
• Network monitoring
• Laboratory terminal testing
• Interoperabilitytesting
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Outline
Introduction
Communication Services –Underlying System configurations
Planning: The ITU-T E-model (G.107 & G.108)
Network Monitoring: P.862, P.863 & P.563
Wideband – The new Challenge
Summary
Reference Connection in the E-model
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Transmission Rating in the E-model
Rating factor R:
With:
R0 – Basic signal to noise ratio (takes into
account circuit noise, room noises)
Ix – Impairment factors (see next slide)
A – Advantage factor (takes into account a
potential advantage for a user for a specific transmission in a specific situation)
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AIe-effIdIsRoR +−−−=
Basic assumption: Psychological factors on the psychological scale are additive
Network planning & E-model (ITU-T G.107 & G.108)
Basis of the E-model: Impairment factors
Simultaneous impairment factor Is (non
optimum loudness rating, non optimum sidetone, PCM coding distortion)
Delayed impairment factor Id (impact of
delay, talker- or listener echo)
Equipment impairment factor Ie (all types
of impairments in equipment such as coding distortion including the effect of packet loss)
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How to derive Ie?
Ie is based on subjective tests and can be derived as follows:
Equipment impairment factors for the most popular codecs in ITU-T G.113
From subjective listening tests described in ITU-T P.833
From objective models (e.g. ITU-T P.863) following the procedure in ITU-T P. 834