1. WATRA/ARTP REGIONAL WORKSHOP
Applicability of the ITU-T Supplement.9 (E.Series): “Guidelines on Regulatory Aspects of QoS” and some best practices
Isaac Annan Laryea
NCA,Ghana
Conakry, Guinea, May 2016

2. Definition of QoS
As per ITU-T Recommendation E.800, quality of service is: “Totality of characteristics of a telecommunications service that bear on its ability to satisfy stated and implied needs of the user of the service.”

3. End to End QoS
Terminal equipment: Contribution to the end-to-end QoS could depend on the variability of the performance of the terminal equipment
Access network: The contributions of access network to the end-to-end QoS depend on the combination of access medium and technology used for a particular service (e.g., wireless, fiber optic, cable, ADSL etc.)
Core network: QoS contribution to end-to-end performance from core network will be governed by the contributions from individual network components (whether single provider or multi providers); technology used (digital multiplexing, IP, etc.) transmission media (air, cable optical or metal) and other factors

4. QoS Interfaces (ITU-T Rec E.800)
Contribution to the end-to-end QoS could depend on the variability of the performance of the terminal equipment.
End-to-end quality Quality related to the performance of a communication system, including all terminal equipment. NOTE – For voice services, it is equivalent to mouth-to-ear quality ([ITU-T P.10]).

5. QoS Framework
End-to-end quality Quality related to the performance of a communication system, including all terminal equipment. NOTE – For voice services, it is equivalent to mouth-to-ear quality ([ITU-T P.10]).

6. QoS Layers in Mobile QoS model for mobile has four layers.
First layer is the Network Availability
defines QoS rather from the viewpoint of the service provider than the service user
Second layer is the Network Access
from user's point of view basic requirement for all the other QoS aspects and parameters
Third layer contains other QoS aspects
Service Access, Service Integrity & Service Retainability
Different services are located in the fourth layer
Their outcome are the QoS parameters as perceived by the user

7. QoS parameters measurements
Different services  different QoS needs
KPIs should be defined separately for each service
Example: voice services - CS
KPI categories
Indicators
Measurements
Service accessability
Coverage availability
Call blockage rate
Call establishment delay
Ec/No, RSCP
Admission control
RAB assignment
Service integrity
Voice quality
Noisy frames (FER), MOS
Service retainability
Dropped calls
Handover failure
No coverage
Interference

8. Relationship between QoS and NP
QoS comprises both network performance and non-network related performance.
Network Performance (NP) is the ability of a network or network portion to provide the functions related to communications between users.
Examples of NP are bit error rate, latency, etc., and non-network performance provision time, repair time, range of tariffs and complaints resolution time, etc.

9. Relationship between QoS and NP
Quality of Service
Non-network related
QoS criteria also called QOE
Network related
QoS criteria
Mapping
Network performance
parameters
Target - range
or limit
Parameter 1
Parameter 2
Parameter N
xxxx
yyyy
zzzz
The NP requirements are the parameters identified as contributing to call clarity: transmission loss, noise (impulsive and non impulsive), echo, delay, crosstalk, voice clipping, (and possibly others);

10. Mapping QoS to Network performance
Network performance applies to the network provider's planning, development, operations and maintenance and is the detailed technical part of QoSO
The achieved QoS is the end-to-end QoS performance derived from measurements.
users/customer's QoS perceived is obtained from customer surveys, consultative workshops and could be indicated by number of complaints.
Corrective action is taken to resolve difference between QoS Perceived and QoS achieved.

11. Activities in quality of service regulation

12. Why quality of service regulation?
• helps customers to make informed choices; • check claims by operators; • understanding the state of the market; • maintaining or improving quality in the presence of competition; • maintaining or improving quality in the absence of competition; • helping operators to achieve fair competition; • making interconnected networks work well together

13. QoS Eco system QoS REGULATIONS SERVICE PROVIDER QOS OFFERED
NETWORK PERFORMANCE QOS
CONSUMER PERCEPTION QOE
QoS REQUIREMENTS

14. Evaluating Methods of QoS
Objective (Quantitative) method This is measured (with instruments or observations) and a performance value assigned quantitatively may be classified with objective parameters. (Eg. error rate of a channel, repair time) Subjective (Qualitative) method Evaluation can be expressed using human judgment and understanding may be classified with subjective or qualitative parameters. (expressed by opinion ratings)

15. Four Viewpoints of QoS (ITU-T Rec G.1000)

16. ITU-T G.1000: Applicability to QoS
Subjective Method (QoSR)
customer’s planned quality requirement of the service.
Objective Method ( QoSO)
Requires network performance measurements and network-centric metrics to estimate the service provider’s offer of QoS.

17. ITU-T G.1000: Applicability to QoS
Objective Method( QoSD)
Requires QoS measurements and user-centric metrics to assess achieved or delivered QoS
Subjective Method (QoSE)
Requires opinion survey rating as per customer’s perception of the service.

18. ITU-T G.1000: Applicability to QoS

19. Relationship b/n Objective & Subjective Evaluation Methods
Objective methods are highly statistical in nature where as subjective methods are empirical and arithmetic
Objective methods are less costly as against Subjective methods which are expensive and time-consuming.
Results of subjective method can serve as input parameters for quality prediction models used in objective evaluation methods.
Both evaluation methods are experiment-based

21. POLQA in Perspective
POLQA - “Perceptual Objective Listening Quality Assessment” - offers new level of benchmarking capability
to determine the voice quality of mobile network services
The limitations of existing standards that are now addressed by POLQA
CDMA
Chinese 3G TD-SCDMA
POLQA will also offer immediate, strong support for testing of new wideband 4G/LTE networks delivering HD-quality voice services
Tests carried out during the POLQA evaluation included future technologies such as
Unified Communications
Next Gen Networks
4G/LTE
HD Voice, i.e. "wide-band" and "super-wide-band"
See POLQA: The Next Generation in Voice Quality Testing

22. List of proposed parameters

23. Main tools for measuring QoS and QoE parameters

24. Key References
E.803: Quality of service parameters for supporting service aspects
E.804: Quality of service aspects for popular services in mobile networks
G.1000-G.1999: Multimedia Quality of Service and performance – Generic and user-related aspects
P.1500-P.1599: Methods for objective and subjective assessment of quality of services other than voice services
Y.1500-Y.1599: Quality of service and network performance
E.807: “Definitions and associated measurement methods of user-centric parameters for call handling in cellular mobile voice service”.
ITU-T Supplement.9 (E. Series): “Guidelines on Regulatory Aspects of QoS” and some best practices worldwide

25. Merci !