UMTS. UMTS V1.0.0 Quality of Service & Network Performance. ETSI SMG Plenary Tdoc SMG 657 / 97 Budapest, October 1997 Agenda Item: 9.

Transcription

1 ETSI SMG Plenary Tdoc SMG 657 / 97 Budapest, October 1997 Agenda Item: 9.3 Source: SMG1 UMTS Universal Mobile Telecommunications System UMTS V1.0.0 Quality of Service & Network Performance This specification is presented at SMG#23 for information.

2 SMG1 WPC TD 97 / TR v Technical Report Special Mobile Group (SMG) Universal Mobile Telecommunication System (UMTS) Quality of Service and Network Performance (UMTS 22.25)

3 2 v TR v ETSI Reference DRAFT ETR (0wc0002r.PDF) Keywords <keyword[, keyword]> ETSI Secretariat Postal address F Sophia Antipolis Cedex - FRANCE Office address 650 Route des Lucioles - Sophia Antipolis Valbonne - FRANCE Tel.: Fax: Siret N NAF 742 C Association à but non lucratif enregistrée à la Sous-Préfecture de Grasse (06) N 7803/88 X.400 c= fr; a=atlas; p=etsi; s=secretariat Internet secretariat@etsi.fr Copyright Notification No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute All rights reserved.

4 3 v TR v Contents Introduction Scope Normative References Normative references Informative references Definitions, Symbols and Abbreviations definitions Symbols Abbreviations General Dependability factors Basic requirement Support of speech Support of data tranmission services UMTS Traffic Requirements Organization of the Quality of Service studies Quality of Service Values General QoS Parameter Values Speech Quality Parameter Values Transmission performance Introduction The Quality of Service of the Universal Mobile Telecommunications System UMTS is an important factor when introducing the system to the customers. A speech quality at least comparable to that of the fixed network is required. When the UMTS is ready to be launched to the mass market, several other mobile telecommunication services exist as an alternative for the general public. A high quality experienced by the user of UMTS is essential in order to promote the idea of UMTS as a global all-purpose communication tool for millions of people with mass produced low price terminal equipment. A possibility to use data services via UMTS in a practical and reliable manner is even more important in the near future than today. There is also a tendency that a larger amount of traffic is taking place between mobile terminals, i.e. traffic within UMTS and between UMTS and other mobile networks. This gives more importance to transcoding and delay quality requirements. 1 Scope This ETR identifies the parameters and parameter values which are to be used as targets when producing UMTS standards and which are to serve as guidelines to operators and service providers for network design and service provision. 2 Normative References References may be made to:

5 4 v TR v a) specific versions of publications (identified by date of publication, edition number, version number, etc.), in which case, subsequent revisions to the referenced document do not apply; or b) all versions up to and including the identified version (identified by "up to and including" before the version identity); or c) all versions subsequent to and including the identified version (identified by "onwards" following the version identity); or d) publications without mention of a specific version, in which case the latest version applies. A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same number. 2.1 Normative references ETR/SMG-50101, UMTS Objectives and Overview ETR/SMG-50201, Framework for the services to be supported by the UMTS ETR/SMG-50601, Quality requirements for speech and associated channel coding for the UMTS 2.2 Informative references CCITT recommendations, E and G series CCITT Rec. X.140 Rec. X.130-X.131, X.134-X.137 and X.200 series 3 Definitions, Symbols and Abbreviations 3.1 Definitions <t.b.d.> 3.2 Symbols <t.b.d.> 3.3 Abbreviations BER EFS MOS Bit error ratio Error free seconds Mean Opinion Score PSTN Public Switched Telephone Network PDNs Public Data Networks

6 5 v TR v General UMTS Quality of Service parameters are defined and their recommended values set for speech, data and voice band data services. Objectives for these requirements are defined in ETR/SMG (UMTS Objectives and Overview) for the actual services which are defined in ETR/SMG (Framework for the services to be supported by the UMTS). As a basis for the speech quality requirements of this ETS is recommendation ETR/SMG (Quality requirements for speech and associated channel coding for the UMTS). A part of the parameters defined in this standard are applicable to all services, some are service-dependent and may have to be supplemented when introducing new services by utilizing the bearer capabilities of UMTS. Quality of service is defined (c.f. CCITT Rec. E.800) as the collective effect of service performances which determines the satisfaction of a user of a service. It is characterized by the combined aspects of performance factors applicable to all services, such as: service operability performance, service accessibility performance, service retainability performance, service integrity performance, and other factors specific to each service. Network performance is defined as the ability of a network or network portion to provide the functions related to communications between users; it contributes to service accessibility, service retainability and service integrity. Network performance parameter values are usually derived from quality of service parameter values (c.f. for example CCITT Rec. I.350). Each category of general service performance factor may be characterized by one or several parameters (measures) which include among others, for service accessibility: service access probability, mean access delay, delay to progress indication, mean delay to dial tone, etc... for service retainability: service retainability probability,

7 premature release probability, release failure probability, release delay, etc... 6 v TR v for service integrity (transmission performance): bit error ratio (BER), error free seconds (EFS), throughput, delay, speech quality probability of loss... Actual parameter values may be specific to a service, to a group of services or apply to all services. For telephony, CCITT recommendations in the E and G series provide some parameter values; for data transmission services, the CCITT Rec. X.140 gives the general definitions of quality of service parameters, while Rec. X.130-X.131 and X.134- X.137 give values for, respectively, circuit-switched and packet-switched services, X.200 series. The following parameters are deemed to be applicable to a large number of services: establishment delay, establishment failure probability, release delay, release failure probability, probability of premature release, unacceptable transmission probability. Service-specific quality of service parameters may include, for the telephony service as an example, speech quality, level of background noise, level of echo, transmission delay, etc... Annex 3 provides indicative values calibrating the parameters using the following arguments: 95% probability, mean, target value, least acceptable value (LAV). This forms the basis of candidate material for standardisation, and must be aligned with the work of the ITU-TS.

8 4.1 Dependability factors 7 v TR v Furthermore, for mobile communication systems, quality of service parameter values also depend on dependability factors (essentially, availability factors) expressed in terms of time availability (% of the time) and radio coverage availability (% of the radio coverage). 4.2 Basic requirement The basic requirement for quality of service parameter values over UMTS is that they should be closely comparable to the corresponding values achieved when using the contemporary fixed networks (e.g. PSTN/ISDN/B-ISDN and PDNs) alone. For Mobliity Services a low handover failure probability is an essential requirement Support of speech A standardised speech codec will be adopted for UMTS. It shall be possible for proprietary speech codecs standardised elsewhere to be deployed as well as the codec standardised for UMTS. This ETR specifies requirements related to the speech codec to be standardised for UMTS. Subjective criteria for assessing quality: subjective quality (measuring: age, sex, language, etc..), speaker recognition, natural speech quality, Ease of conversation, perception of echo, loss of interactivity due to delay: two party conversations, delay in the two-way speech path, dual talk, multi-party and multi-speaker. background noise. Essential quality of service parameters for measuring speech are: 1. maximum transmission delay, 2. maximum echo level, 3. Mean Opinion Score (MOS) Support of data tranmission services Essential quality of service parameters for data transmission services are: 1. transmission delay,

9 2. bit error rate 3. throughput, 4. probability of loss. 5. delay variation 8 v TR v UMTS Traffic Requirements The support of User to User Bearer Requirements and Teleservices results in the required modelling of the corresponding traffic profiles; c.f. annex 3 for initial modelling. These traffic profiles may result in inefficiencies which coding may exploit within the network and radio interfaces. 4.4 Organization of the Quality of Service studies The studies, based on hypothetical reference connections and on the objective values of quality of service parameters given for PSTN/ISDN/B-ISDN (including Corporate and private networks) and PDNs and Teleservices, should identify for each quality of service parameter the contribution of UMTS and the eventual relative performance deviation. The following categories of service/network interworking will be considered, especially with respect to echo and delay and with compliance to G.131: UMTS Mobile-to-mobile communications transiting through a supporting network. Mobile to non-umts communications transiting through a supporting network. NOTE: A supporting network is any network which provides UMTS functionality, access to UMTS functionality, or transportation of services using UMTS functionality. This may include the fixed network (including mobile overlay networks), satellite networks, radio and mobile access networks. The work of translating quality of service parameter values into network performance values assigned to different sections of UMTS connections is to be subsequently spread between the groups that will work respectively on the radio interface and on the network aspects. 5 Quality of Service Values The values in the tables below illustrate the type of Quality of Service parameters and values which are required to support UMTS. These tables are proposed as candidate material for this standardisation proposes. When standardised this information must be aligned with the output of ITU-T (CCITT): SG2 on network performance and teleservices; SG7 on data services and SG12 on end to end transmission requirements. It is proposed to liaise with ETSI SMG1 and NA4, and to the relevant ITU-T Study Groups, as a result of which, it is hoped, that the process of alignment may begin.

10 9 v TR v General QoS Parameter Values Table : User Perspective Mean 95% Network response to frequent user actions (e.g. time to attach and get alerting/ringing) 2 s < 5 s Network response to rare non critical user actions (e.g. roaming updating with automatic roaming agreement) 5 s < 30 s Answer/connect time - when called party accepts the call < 100 ms < 200 ms Release time < 100 ms < 200 ms Interruption of services 0 0 Probability of Probability value Note Premature disconnection No disconnection desired even if temporary loss of network coverage Network congestion - up to network design User service requirements not met - up to network design The system shall be capable of performing seamless handover not detectable via the audio path by the user. As a guideline for speech, the break shall be less than [20 ms]. For bearer services in general, issues related to extra delay and loss of data due to handover need to be considered as well as maintaining synchronisation (e.g. between video and speech) in case of multiple simultaneous bearers. 5.2 Speech Quality Parameter Values Delay (one way end-to-end) 40 ms Mean Opinion Score as in G.722

11 Echo <to be defined> 10 v TR v Music: The sound quality of music shall be acceptable and not annoying. Background noise: It is desirable eliminate background noise so that the discontinuous nature of speech can be fully exploited. Tandeming: UMTS to a prorietary codec, an other UMTS codec, GSM codec or fixed network codec etc. shall be no worse than the worst codec. The codec shall facilitate speaker recognition of different sexes, and not discriminate between languages, ages or ethnic groups. Multiple speakers: The codec should be able to handle multiple simultaneous speakers in cases like: - several users at a single terminal - multiparty call Graceful degradation in deteriorating radio conditions: For the UMTS speech codec it is required that it can adapt to provide good quality speech even when radio conditions deteriorate. The codec should adapt to good quality speech even if there is a temporary deterioration of the radio environment. Graceful speech quality quality degradation is required if speech quality degradation is not unavoidable. If the detorioration of the radio environment is more permanent any degradation in speech quality should not be annoying to the user. 5.3 Transmission performance See ETS for values of parameters: bit error ratio (BER), error free seconds (EFS), throughput,

12 delay, probability of loss v TR v.1.0.1