1、 International Telecommunication Union ITU-T H.362TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2010) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Quality of service architecture for audiovisual and multimedia services A framework for adaptive end-to-end Q
2、oS control based on variable bit-rate codecs in wireless networks Recommendation ITU-T H.362 ITU-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES General H.200H.219 Transmission multiplexing an
3、d synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures H.240H.259 Coding of moving video H.260H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349 Directory services architecture for audiovisual and multimedia services
4、H.350H.359 Quality of service architecture for audiovisual and multimedia services H.360H.369Supplementary services for multimedia H.450H.499 MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definitions, protocols and procedures H.500H.509 Mobility for H-Series multimedi
5、a systems and services H.510H.519 Mobile multimedia collaboration applications and services H.520H.529 Security for mobile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559 Mobile m
6、ultimedia collaboration inter-working procedures H.560H.569 BROADBAND, TRIPLE-PLAY AND ADVANCED MULTIMEDIA SERVICES Broadband multimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700H.71
7、9 IPTV terminal devices H.720H.729 IPTV middleware H.730H.739 IPTV application event handling H.740H.749 IPTV metadata H.750H.759 IPTV multimedia application frameworks H.760H.769 IPTV service discovery up to consumption H.770H.779 For further details, please refer to the list of ITU-T Recommendatio
8、ns. Rec. ITU-T H.362 (09/2010) i Recommendation ITU-T H.362 A framework for adaptive end-to-end QoS control based on variable bit-rate codecs in wireless networks Summary Recommendation ITU-T H.362 describes a framework for adaptive end-to-end quality of service (QoS) control using variable bit-rate
9、 codecs in wireless networks. Specifically, this Recommendation describes a reference network architecture, functional entities, references points, a terminal architecture, and signalling flows between functional entities. The framework in this Recommendation can be used for application level QoS su
10、pport to control the multimedia service quality adaptively in wireless networks where the network status may change over time. History Edition Recommendation Approval Study Group 1.0 ITU-T H.362 2010-09-13 16 ii Rec. ITU-T H.362 (09/2010) FOREWORD The International Telecommunication Union (ITU) is t
11、he United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Re
12、commendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. T
13、he approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Admi
14、nistration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and c
15、ompliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendati
16、on is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claime
17、d Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendati
18、on. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2011 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, withou
19、t the prior written permission of ITU. Rec. ITU-T H.362 (09/2010) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Adaptive QoS control framework for wireless networks . 3
20、5.1 Reference network architecture 3 5.2 Functional entities 4 5.3 Interfaces between functional entities 5 5.4 Terminal architecture for codec mode control . 5 5.5 Functional descriptions . 7 Rec. ITU-T H.362 (09/2010) 1 Recommendation ITU-T H.362 A framework for adaptive end-to-end QoS control bas
21、ed on variable bit-rate codecs in wireless networks 1 Scope There are various wireless networks including 2G/3G/4G mobile networks, wireless LANs, and mobile WiMAX networks. On the other hand, there are various multi-rate codecs including ITU-T G.729.1, ITU-T G.722.2, and ITU-T H.264, which can prov
22、ide variable bit rates and adaptability in the dynamic environment where the network status may change over time. Networks are being evolved toward the converged network where heterogeneous wired/wireless access networks are converged using the IP-based core network. Fixed mobile convergence (FMC) a
23、nd fixed mobile substitution (FMS) are some examples. In such an environment, many of the QoS control mechanisms are employed in the core/access networks to manage QoS resources efficiently. However, this type of QoS control may not be sufficient to meet the end users expectation from the end-to-end
24、 QoS perspective because QoS control at the application level is not involved. To provide more complete end-to-end QoS, the application level QoS support can be useful. This is particularly important when the network is not able to support QoS. One of the possible application level QoS mechanisms is
25、 codec-based QoS control which adjusts encoding parameters such as codec bit rate or codec mode according to the network status, e.g., wireless channel status. Various codec-based QoS mechanisms were proposed to control the codec bit rate and call capacity using the wireless channel information in d
26、iverse wireless networks. However, in the heterogeneous network environment, it is difficult to control QoS in a unified way and to achieve the desirable service quality. Therefore, it is useful to design a common framework to control the codec mode adaptively, according to the channel status in wir
27、eless networks and reflect the users perceived quality. For achieving the objective, this Recommendation describes a framework for adaptive end-to-end QoS control using variable bit-rate codecs in wireless networks. Specifically, this Recommendation describes a reference network architecture, functi
28、onal entities, references points, a terminal architecture, and signalling flows between functional entities. The stability of control loop and delayed feedback in the control path which may affect the service quality is important in such an adaptive QoS control; however, it is out of scope of this R
29、ecommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are sub
30、ject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document
31、 within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T G.711.1 Recommendation ITU-T G.711.1 (2008), Wideband embedded extension for G.711 pulse code modulation. ITU-T G.722.2 Recommendation ITU-T G.722.2 (2003), Wideband coding of speech at aro
32、und 16 kbit/s using Adaptive Multi-Rate Wideband (AMR-WB). ITU-T G.729.1 Recommendation ITU-T G.729.1 (2006), G.729-based embedded variable bit-rate coder: An 8-32 kbit/s scalable wideband coder bitstream interoperable with G.729. 2 Rec. ITU-T H.362 (09/2010) ITU-T H.245 Recommendation ITU-T H.245 (
33、2008), Control protocol for multimedia communication. ITU-T H.264 Recommendation ITU-T H.264 (2009), Advanced video coding for generic audiovisual services. ITU-T H.323 v7 Recommendation ITU-T H.323 (2009), Packet-based multimedia communications systems. ITU-T M.2301 Recommendation ITU-T M.2301 (200
34、2), Performance objectives and procedures for provisioning and maintenance of IP-based networks. ITU-T Y.1541 Recommendation ITU-T Y.1541 (2006), Network performance objectives for IP-based services. 3 Definitions 3.1 Terms defined elsewhere This Recommendation does not use any particular terms defi
35、ned elsewhere. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 base station (BS): A radio receiver/transmitter that serves as the hub of the wireless access network and connects the wireless stations (WSTAs) to the IP-based network. 3.2.2 codec mode (C
36、M): A specific bit-rate of a variable bit-rate codec. 3.2.3 quality-of-service control function (QCF): A service quality control function capable of managing the codec mode to control the amount of traffic from/to WSTAs or packet transfer characteristics such as delay, loss, and jitter. 3.2.4 variab
37、le bit-rate codec (VBRC): A multi-mode codec which can support a set of variable bit rates, e.g., ITU-T G.711.1, ITU-T G.722.2, ITU-T G.729.1, and ITU-T H.264. 3.2.5 wireless station (WSTA): A terminal which provides wireless access to the end user and is equipped with one or more variable bit-rate
38、codec(s). 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: BS Base Station CI Codec Information CMC Channel Measurement Command CMC_REQ Codec Mode Change Request CMC_RESP Codec Mode Change Response CMCM Codec Mode Control Module COCM Codec Operation Con
39、trol Module CQ Channel Quality CSMMF Channel Status Measurement and Management Function MDP Multimedia Decoding Parameters MEP Multimedia Encoding Parameters Rec. ITU-T H.362 (09/2010) 3 OSS Operations Support System PCF Policy Control Function PEM Packet Evaluation Module PMC Packet Measurement Com
40、mand PMP Packet Measurement Parameters QCF QoS Control Function QoS Quality of Service QSF QoS Signalling Function RSSI Received Signal Strength Indicator RTP Real-time Transport Protocol RTSP Real-time Streaming Protocol RxCMCR Received Codec Mode Change Request SIP Session Initiation Protocol SIR
41、Signal-to-Interference Ratio SQ Service Quality SQCF Service Quality Control Function SQMM Service Quality Measurement Module TxCMCR Transmitting Codec Mode Change Request VBRC Variable Bit-Rate Codec WAI Wireless Access Interface WCMM Wireless Channel Measurement Module WSTA Wireless Station 5 Adap
42、tive QoS control framework for wireless networks 5.1 Reference network architecture Figure 1 shows a reference network architecture for adaptive QoS control using variable bit-rate codecs, which consists of wireless stations (WSTAs), base stations (BSs), QoS control functions (QCFs), wireless access
43、 networks, and an IP-based core network. Variable bit-rate codecs, such as ITU-T G.711.1, ITU-T G.722.2, ITU-T G.729.1, and ITU-T H.264, can be employed at each WSTA for multimedia services and used for adaptive QoS control when the network experiences QoS degradation due to poor wireless channel qu
44、ality or packet transfer performance, e.g., high packet loss, delay, and jitter. When a WSTA detects the quality of the wireless channel, it can communicate with a QCF in the local site where the WSTA is located and its counterpart WSTA in the remote site to control the codec mode. QCFs in the local
45、 and remote sites can communicate with each other to exchange the codec mode information of the WSTAs. 4 Rec. ITU-T H.362 (09/2010) Figure 1 Conceptual reference network architecture for adaptive QoS control using variable bit-rate codecs 5.2 Functional entities 5.2.1 Wireless station A wireless sta
46、tion (WSTA) is a terminal which provides wireless access to the end user and is equipped with one or more variable bit-rate codecs. The WSTA monitors the signal strength of the downlink channel and measures key performance parameters such as signal-to-interference ratio (SIR). The WSTA also measures
47、 perceived service quality by examining received packets and utilizing an objective quality measurement method. Based on the measurement result, the WSTA determines if the codec mode needs to be changed. If it is necessary to change the codec mode for QoS control, the WSTA sends a codec mode change
48、request to the QCF in the local site where the WSTA is associated. It is also possible for the WSTA to have a service quality control function (SQCF) that can control the codec mode, according to the measured wireless channel quality and packet transfer performance and to communicate with the SQCF i
49、n the remote WSTA. 5.2.2 Base station A base station (BS) is a radio receiver/transmitter that serves as the hub of the wireless access network, which communicates with the WSTA. The BS monitors the signal strength of the uplink channel and measures key performance parameters such as SIR. After measuring the uplink channel quality, the BS calculates the adequate signal power for uplink transmission and commands the WSTA to control the uplink signal power, if necessary. If there is any request from the WSTA t
