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ITU p 862

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  Perceptual evaluation of speech quality (PESQ) is a one-way listening model. It estimates user-perceived MOS by comparing the transmitted reference speech signal and the received degraded signal. The model takes into account impairment effects due to voice compression and IP network parameters (e.g. jitter and packet loss), in addition to conventional circuit-switched network impairments, such as noise and echo (ITU-T Rec. P.862). ITU-T Rec. P.863 (also known as perceptual objective listening quality assessment –  POLQA) incorporates current industry requirements and allows for assessment of super-wideband speech, as well as networks and codecs that introduce time warping. It includes different test factors and different existing coding technologies for voice such as G-series ITU voice codes, 3GPP codecs such as GSM and AMR, Skype codecs, etc. One may distinguish between parameters for specific service types. For example, there are a number of standards that relate to conversation or voice quality (ITU-T Recs. G.107, G.108.2, G.109 and P.862/P.863). ITU-T Rec. E.804 (02/2014): Quality of service aspects for popular services in mobile networks. QoS regulation is based on a selection of so-called QoS parameters, which can be technical (examples in ITU-T Rec. 804) and non-technical (examples in ITU-T Rec. E.803). SDOs, such as the ITU, standardize QoS parameters for different services. For example, ITU-T Rec. E.804 defines QoS parameters for popular mobile services. ITU-T Rec. 803 defines parameters for supporting aspects of QoS. Not all QoS parameters are subject to regulation. The selected QoS parameters which are important to users, operators and the regulator are referred to as KPIs, as mentioned earlier. Different countries have specific characteristics regarding their QoS parameters and therefore their target values may vary from country to country for a number of reasons (e.g. low penetration of certain services, early years of development of certain services in that country, etc.). Some variations of standard parameters may be necessary, depending on the specific situation in a given country or sector. The measurements of a parameter might need to distinguish between:    Market segments: QoS may be different for private consumers, small and large businesses or for wholesale and retail offerings.    Reporting areas: areas likely to have differences in quality, such as rural and urban areas.     Operators: who have few customers, that resell services from other operators, or that are not dominant in the market might be exempted from monitoring parameters or publishing measurements.    Services: parameters may be specific to services such as voice, text messages and Internet, television and radio broadcasting, as well as leased lines, as the main services that have most impact on users. The recent list of QoS parameters is provided in ITU-T Rec. E.803, [21] which lists 88 different QoS parameters (see the 2011 version), while QoS parameters for popular mobile services are defined in ITU-T Rec. E.804. Below are different types of QoS parameters defined in ITU-T Rec. E.803:    Preliminary information on ICT services (Parameter 2)  Pricing transparency: is characterized by clarity, conciseness and unambiguity in every tariff structure for all usage conditions for every service provided by the service provider. Measured as: opinion rating.    Contractual matters between ICT service providers and customers (Parameter 5)  Integrity of contract information: true and fair view of pertinent information on supply, maintenance and cessation of a telecommunication service provided by a service provider. Measured as: opinion rating.    Provision of services (Parameter 9)  Meeting promised provisioning date: successful completion of provisioning of service on the date promised in the contract in relation to the total number of signed contracts with promised service provisioning dates. Measured as: ratio or percentage.    Service alteration (Parameter 17)  Time for alteration of service: time elapsed from the instant alteration notification is received by the user to the instant the alteration is completed. Measured as: time.    Technical upgrade of ICT services (Parameter 26)  Time for technical upgrade of a service: time elapsed from the instant the technical upgrade period was announced to the user to the instant the technical upgrade was carried out. Measured as: time.    Documentation of services (operational instructions) (Parameter 36)  Documentation of delivery time: time taken from the instant a service is provided to the instant documentation for the commissioning and use of the service is delivered to the customer. This parameter measured as: time.    Technical support provided by service provider (Parameter 42)  Accessibility to technical support: ratio of the number of successful attempts to technical support to the total number of attempts to reach this support. Measured as: ratio or percentage.    Commercial support provided by service provide (Parameter 49)  Commercial solution delivery time: time elapsed from the instant the customer raised a problem with commercial support to the instant a solution was achieved. Measured as: time.    Complaint management (Parameter 54)  Accessibility of the complaint management: ratio of the number of successful attempts to the total number of  attempts to reach complaint management (CM) in a specified period. Measured as: ratio or percentage.    Repair services (Parameter 62)  Successful repairs carried out within a specified period of time: ratio of the number of repairs successfully carried out to the total number of repair requests accepted by the SP within a specified period. Measured as: ratio or percentage.    Charging and billing (Parameter 68)  Accessibility of tariff information: ratio of the number of successful attempts to the total number of attempts to reach this facility located as indicated in the contract or regulations (access details to this facility to be provided by the service provider). Measured as: ratio or percentage.    Network/Service management by customer (Parameter 78)  Outage duration: the total time a network/service management facility is not accessible to the customer during a specified reporting period. Measured as: time.    Cessation of service (Parameter 85)  Cessation acknowledgement time: time elapsed from the instant of sending the cessation request to the instant of receipt by the customer of the acknowledgment from the SP. Measured as: time. However, individual data applications may have a specific set of KPIs which are dependent upon their functional definition. For example, the web is the most used best-effort service, which is standardized by the IETF. Standardized QoS parameters in ITU-T E.804 (popular mobile services) for web browsing are:    HTTP service non-accessibility [%]  is the probability that a subscriber cannot establish a PDP (Packet Data Protocol) context and access the service successfully.    HTTP set-up time [s]  is the time period needed to access the service successfully, from starting the dial-up connection to the point of time when the content is sent or received.    HTTP IP-service access failure ratio [%]  is the probability that a subscriber would not be able to establish a TCP/IP connection to the server of a service successfully.    HTTP IP-service set-up time [s]  is the time period needed to establish a TCP/IP (transmission control protocol/Internet Protocol) connection to the server of a service, from sending the initial query to a server to the point of time when the content is sent or received.    HTTP session failure ratio [%]  is the proportion of uncompleted sessions and sessions that were started successfully.    HTTP session time [s]  is the time period needed to successfully complete a PS (packet switched) data session.    HTTP mean data rate [kbit/s] : After a data link has been successfully established, this parameter describes the average data transfer rate measured throughout the entire connect time to the service. The data transfer shall be successfully terminated. The prerequisite for this parameter is network and service access.    HTTP data transfer cut-off ratio [%]  is the proportion of incomplete data transfers and data transfers that were started successfully.  Quality of Service Regulation Manual 76 Example of QoS parameter definition (for HTTP) –  HTTP Mean Data Rate [kbit/s]: Abstract definition: After a data link has been successfully established, this parameter describes the average data transfer rate measured throughout the entire connect time to the service. The data transfer shall be successfully terminated. The prerequisite for this parameter is network and service access. Abstract equation: Trigger points for HTTP Mean Data Rate are provided in Table 5.5. Figure 5.9 QoS aspects and the corresponding QoS parameters (Source: ITU-T Rec. E.804.) QoS for mobile services is covered in ITU- T Rec. E.804, “QoS aspects for popular services in mobile networks”, [30] and explained below. Mobile services are grouped into:      Direct mobile services:  QoS parameters are defined for the following direct services:
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