1、 ATIS-0800056 TECHNICAL REPORT ON MOBILE IPTV QUALITY OF SERVICE As a leading technology and solutions development organization, ATIS brings together the top global ICT companies to advance the industrys most-pressing business priorities. Through ATIS committees and forums, nearly 200 companies addr
2、ess cloud services, device solutions, M2M communications, cyber security, ehealth, network evolution, quality of service, billing support, operations, and more. These priorities follow a fast-track development lifecyclefrom design and innovation through solutions that include standards, specificatio
3、ns, requirements, business use cases, software toolkits, and interoperability testing. ATIS is accredited by the American National Standards Institute (ANSI). ATIS is the North American Organizational Partner for the 3rd Generation Partnership Project (3GPP), a founding Partner of oneM2M, a member a
4、nd major U.S. contributor to the International Telecommunication Union (ITU) Radio and Telecommunications sectors, and a member of the Inter-American Telecommunication Commission (CITEL). For more information, visit . Notice of Disclaimer Progressive Download and Dynamic Adaptive Streaming over HTTP
5、 (3GP-DASH).11This document is available from the Third Generation Partnership Project (3GPP) at . ATIS-0800056 2 7 IEEE Std 802.16-2009, Part 16: Air Interface for Broadband Wireless Access.28 Stockhammer, Thomas (Qualcomm Incorporated); Dynamic Adaptive Streaming over HTTP Design Principles and St
6、andards.39 ITU-T FG IPTV-DOC-0199, IPTV vocabulary of terms.410 ITU-T FG IPTV-DOC-0182, IPTV service scenarios.411 ISO/IEC 23009-1:2012, Information technology Dynamic adaptive streaming over HTTP (DASH) Part 1: Media presentation description and segment formats.512 3GPP TS 32.425, Performance measu
7、rements Evolved Universal Terrestrial Radio Access Network (E-UTRAN).13 Definitions, Acronyms, it could be, among other things: a smart phone, a laptop, a tablet, a desktop computer, a game console, an in-vehicle entertainment system, or even a TV set. 2This document is available from the Institute
8、of Electrical and Electronics Engineers (IEEE). 3This document is available at . 4This document is available from the International Telecommunications Union. 5This document is available from the International Organization for Standardization. ATIS-0800056 3 3.1.6 Mobile IPTV Services Mobile IPTV ser
9、vice requirements are a subset of the IPTV service requirements as specified in ATIS-0800007, IPTV High-Level Architecture, and apply to where the Consumer ITF is connected to the IPTV Service Provider via an IPTV-enabled mobile network. The architectural requirements of Mobile IPTV comply with all
10、existing requirements of ATIS IIF IPTV specifications while also supporting mobility (per ITU-T Q.1706/Y.2801) and resources for the ITF. 3.1.7 Mobile Network A network that is established and operated by an administration or by a recognized operating agency (ROA) for the specific purpose of providi
11、ng land mobile telecommunications services to the public. See the ATIS Telecom Glossary . 3.1.8 Upstream The direction opposite to the data flow. See the ATIS Telecom Glossary . NOTE In mobile network, this is often referred to as “uplink”, where the signal goes from the mobile device to the base st
12、ation. 3.2 Acronyms the exchange of billing data; service management information, including mobile network link monitoring data; and information enabling the assessment of the delivered content quality. ATIS-0800056 6 5.1.1 3GPP 3GPP is a grouping of SDOs around the world with the mandate to develop
13、 and maintain GSM technical specifications and reports, as well as the evolution to 3G mobile systems and beyond.6It supports various communication protocols between base stations and mobile users, such as UMTS/HSPA7, LTE, and the recent new addition of LTE-Advanced. These technologies are capable o
14、f delivering broadband services to mobile devices, including mobile IPTV services. 5.1.1.1 Universal Mobile Telecommunications System (UMTS) In order to understand UMTS QoS mechanisms and definitions, it is important to understand the various components of a typical UMTS architecture. This is shown
15、in Figure 1 below from 1. TE MT RANCN EDGENODECN Gateway TEUMTSEnd-to-End ServiceTE/MT Local Bearer Service UMTS Bearer Service External BearerService Radio Access Bearer Service CN BearerServiceBackboneBearer ServiceRA N A ccessBearer ServiceRadio BearerService Physical Radio Bearer ServicePhysical
16、 Bearer ServiceFigure 1: 3GPP UMTS QoS Layered Architecture NOTES: 1. TE (Terminal Equipment) refers to either the hardware equipment connected to the Mobile Terminal (MT) (i.e., mobile device) or a software application inside the MT. 2. End-to-end QoS is used at the application layer; all the other
17、 aspects of the QoS architecture depicted in Figure 1 above are found at layers below that. 6Previous 3GPP technologies such as GPRS and EDGE, based on GSM, are not considered, as most of the 3GPP networks deployed are either already using UMTS/HSPA or are in the process of upgrading to this technol
18、ogy. 7HSPA is an enhancement of the UMTS (3G) technology, supporting higher data rates for both downstream (Core Network to device) and upstream (device to Core Network). ATIS-0800056 7 3. A major contributor to QoS is usually the Physical Radio Bearer Service, the radio interface between the MT and
19、 the Base Station that is part of the Radio Access Network (RAN). 5.1.1.1.1 QoS Classes of Services Concept As can be seen in the UMTS architecture8diagram in Figure 1, UMTS uses four QoS classes (also referred to as traffic classes). Those traffic classes are explained in more detail in Table 1 bel
20、ow: Table 1: UMTS QoS Classes Traffic class Conversational classConversational RT Streaming classStreaming RT Interactive class Interactive best effort BackgroundBackground best effort Fundamental characteristics Preserve time relation (variation) between information entities of the stream. Conversa
21、tional pattern (stringent and low delay).Preserve time relation (variation) between information entities of the stream. Request-response pattern. Preserve payload content. Destination is not expecting the data within a certain time.Preserve payload content. Example of the application Voice. Streamin
22、g video. Web browsing. Background download of emails.As indicated previously, the physical limitation of the mobile network air interface (between the MT and the base station in the RAN) is a major factor when considering QoS. Due to the inherent environment of the mobile networks air interface, QoS
23、 mechanisms need to be robust and capable of providing reasonable level of QoS for the user. This has been the driving factor for the development of the classes defined in Table 1 above. The predominant factor between the four 3GPP UMTS QoS classes is the average users sensitivity to transmission de
24、lays. For example, the conversational class describes services where the users sensitivity to delays is very high, while consumers of background class services tolerate rather high delays. Conversational and streaming classes are mainly intended to be used to carry real-time traffic. Conversational
25、real-time services, like telephony (including video telephony), are the most delay-sensitive applications. Interactive and background classes are mainly meant for traditional Internet applications like web browsing, email, and the download of files. Both classes can achieve acceptable QoS for users
26、with low error rates through channel coding and retransmission, since they have less stringent delay requirements compared to conversational and streaming classes. The main difference between interactive and background class is that the interactive class is mainly used by interactive applications (e
27、.g., online gaming) while the background class is meant for background traffic (e.g., background download of emails or background file downloading). Responsiveness of the interactive applications is ensured by separating interactive and background applications. Traffic in the Interactive class has h
28、igher priority in scheduling than background class traffic, so background applications use transmission resources only when interactive applications do not need them. This is very important in wireless environment where UMTS bandwidth availability is usually lower than fixed networks. In relation to
29、 mobile IPTV service, the most appropriate QoS class to use is streaming. 5.1.1.1.2 QoS Parameters For each of the 3GPP QoS classes, there are a certain number of parameters (called attributes) that can be set as shown in Table 2 below. 8For more details on the interactions between the various layer
30、s of the 3GPP QoS architecture, the reader is referred to 3GPP TS 23.107 1. ATIS-0800056 8 Table 2: 3GPP QoS Classes Parameters Traffic class Conversational class Streaming class Interactive class Background classMaximum bit rate X X X X Delivery order X X X X Maximum SDU size X X X X SDU format inf
31、ormation X X Transfer delay X X Guaranteed bit rate X X Traffic handling priority X Allocation/Retention priority X X X X Source statistics descriptor X X Signalling indication X Evolved Allocation/Retention priority X X X X Where: Traffic Class (“conversational”, “streaming”, “interactive”, “backgr
32、ound”) The type of expected traffic from the application, in order to optimize the resources to render the service. Maximum Bit Rate (kbps) The maximum number of bits which will be allowed to be delivered or received within a period of time. NOTE: The UMTS bearer service will be supported up to this
33、 bit rate. This parameter is used for resource allocation within UMTS network. This is the upper limit resource for the applications traffic transmitted within the UMTS network. Guaranteed Bit Rate (kbps) The guaranteed number of bits delivered or received within a period of time. NOTE: Guaranteed b
34、it rate may be used to facilitate admission control based on available resources, as well as for resource allocation within UMTS network. Examples where this is useful are conversational class speech service and streaming class video service (such as IPTV). The UMTS bearer service is not required to
35、 transfer traffic at a rate exceeding the guaranteed bit rate. UMTS bearer service parameters e.g., delay and reliability attributes are guaranteed for traffic up to the guaranteed bit rate. Delivery order (y/n) Indicates if the UMTS bearer will provide in-sequence Service Data Unit (SDU) delivery o
36、r not. NOTE: This parameter depends on the PDP type and the specified reliability; this will dictate whether out-of-sequence SDUs are dropped or re-ordered. Delivery order should be set to no for PDP Type = IPv4 or IPv6. ATIS-0800056 9 Maximum SDU Size (octets) The maximum SDU size for which the net
37、work will satisfy the negotiated QoS. NOTE: The maximum SDU size is used for admission control and policing and/or optimizing transport. It is applicable only if SDU format information is not specified (see below). It will usually be applicable for interactive and background classes. SDU Format Info
38、rmation (bits) The possible exact sizes of SDUs. NOTE: RAN requires this information to operate in transparent Radio Link Control (RLC) protocol mode (no RLC retransmissions). This mode is considered for conversational and streaming class services. For these services, RLC Protocol Data Unit (PDU) si
39、ze is adapted to UMTS bearer SDU sizes and therefore RLC retransmission is not used. This minimizes delay and is more spectral efficient (so a less expensive bearer). Transfer Delay (ms) Maximum delay for the 95thpercentile of the distribution of delay for all delivered SDUs during the lifetime of a
40、 bearer service, where delay for an SDU is defined as the time from a request to the transfer of an SDU at one Service Area Point (SAP) to its delivery at the other SAP. NOTE: This specifies the delay tolerance for the applications traffic and is applicable only to conversational and streaming class
41、es. This is because the traffic needs to be non-bursty, which is usually the case for these service classes. Used in conjunction with the SDU error ratio parameter, the specified value states the time interval in which most of the applications transmitted packets need to be delivered. This parameter
42、 allows RAN to set transport formats and Automatic Repeat reQuest (ARQ) parameters. Traffic Handling Priority The relative importance for handling of SDUs within the interactive class. NOTE: This allows assignment of different category prioritization between various interactive class traffic types,
43、which are scheduled internally by the UMTS. Allocation/Retention Priority The relative importance of an UMTS bearer compared to other UMTS bearers for allocation and retention. NOTE: The Allocation/Retention Priority parameter is set on a per-subscription basis, although its value might be changed e
44、ither by the Serving GPRS Support Node (SGSN) or the Gateway GPRS Support Node (GGSN) network element. In situations where resources are scarce, the relevant network elements can use the Allocation/Retention Priority to prioritize bearers with a high Allocation/Retention Priority over bearers with a
45、 low Allocation/Retention Priority when performing admission control. Source statistics descriptor (“speech”/”unknown”) The characteristics of the source of submitted SDUs. NOTE: Conversational speech has a well-known statistical behavior. By being informed that the SDUs for a UMTS bearer are genera
46、ted by a speech source, the RAN, SGSN, GGSN, and the UE may, based on experience, calculate a statistical multiplex gain for use in admission control on the relevant interfaces. Signalling Indication (Yes/No) The signalling nature of the submitted SDUs. NOTE: This parameter is complementary to the o
47、ther QoS parameters and does not over-ride them. This parameter is only defined for the interactive traffic class. If signalling indication is set to “Yes”, the UE should set the traffic handling priority to “1”. Signalling traffic can have different characteristics than other interactive traffic AT
48、IS-0800056 10 e.g. higher priority, lower delay, and increased peakiness. This parameter permits enhancing the RAN operation accordingly. An example use of the Signalling Indication is for IMS signalling traffic. This indication is sent by the UE in the QoS IE. Evolved Allocation/Retention Priority
49、Enhances the Allocation/Retention Priority parameter with an increased value range of the priority level, as well as additional information about the preemption capability and the preemption vulnerability of the UMTS bearer. NOTE: The preemption capability information defines whether a bearer with a lower priority level should be dropped to free up required resources for a higher-priority UMTS bearer or an UMTS bearer requiring guaranteed bit rate. The preemption vulnerability information defines whether a UMTS bearer is a candidate for d
