1、 ETSI TR 126 947 V15.0.0 (2018-07) Universal Mobile Telecommunications System (UMTS); LTE; Multimedia Broadcast/Multicast Service (MBMS); Selection and characterisation of application layer Forward Error Correction (FEC) (3GPP TR 26.947 version 15.0.0 Release 15) TECHNICAL REPORT ETSI ETSI TR 126 94
2、7 V15.0.0 (2018-07)13GPP TR 26.947 version 15.0.0 Release 15Reference RTR/TSGS-0426947vf00 Keywords LTE,UMTS ETSI 650 Route des Lucioles F-06921 Sophia Antipolis Cedex - FRANCE Tel.: +33 4 92 94 42 00 Fax: +33 4 93 65 47 16 Siret N 348 623 562 00017 - NAF 742 C Association but non lucratif enregistr
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9、ciation. ETSI ETSI TR 126 947 V15.0.0 (2018-07)23GPP TR 26.947 version 15.0.0 Release 15Intellectual Property Rights Essential patents IPRs essential or potentially essential to normative deliverables may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publ
10、icly available for ETSI members and non-members, and can be found in ETSI SR 000 314: “Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect of ETSI standards“, which is available from the ETSI Secretariat. Latest updates are available on the ETSI
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13、e or reproduce any trademark and/or tradename. Mention of those trademarks in the present document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Report (TR) has been produced by ETSI 3rd Generation Partners
14、hip Project (3GPP). The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI ident
15、ities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verbs terminology In the present document “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expres
16、sion of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 126 947 V15.0.0 (2018-07)33GPP TR 26.947 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 6g3Introduc
17、tion 6g31 Scope 8g32 References 8g33 Definitions, symbols and abbreviations . 8g33.1 Definitions 8g33.2 Abbreviations . 9g34 Use of FEC in MBMS 9g34.1 Introduction 9g34.2 Architecture 9g34.3 MBMS Bearer in UTRAN . 10g34.4 MBMS Bearer in E-UTRAN 10g34.5 Streaming Delivery User Service . 10g34.5.1 Int
18、roduction. 10g34.5.2 Transport in streaming delivery service 10g34.5.3 Examples 11g34.6 Download Delivery User Service . 11g34.6.1 Introduction. 11g34.6.2 Transport in download delivery service 12g34.6.3 Download Examples . 12g34.7 Streaming using DASH and Download Delivery User Service 13g35 MBMS B
19、earer Service Channel Modelling . 13g35.1 Introduction 13g35.2 Modelling of UTRAN MBMS Bearer 13g35.3 Modelling of E-UTRAN MBMS Bearer 14g36 FEC Evaluation Procedure . 17g36.1 Introduction 17g36.2 Simulation Conditions 17g36.2.1 Simulation conditions and assumptions (UTRAN). 17g36.2.2 Simulation con
20、ditions and assumptions (LTE eMBMS) 18g36.3 Code Performance 19g36.3.1 Introduction. 19g36.3.2 Method 1 . 19g36.3.2.1 Evaluation Procedure 19g36.3.2.2 Test Cases . 21g36.3.2.3 Performance Metrics . 21g36.3.3 Method 2 . 22g36.3.3.1 Evaluation Procedure 22g36.3.3.2 Test Cases . 22g36.3.3.3 Performance
21、 Metrics . 23g36.4 Download Performance 24g36.4.1 Performance Metrics. 24g36.4.2 Download Performance over UTRAN 24g36.4.3 Download Performance over LTE 25g36.5 UTRAN Streaming Performance . 28g36.6 Streaming Performance over LTE 29g36.6a Implementation-specific Performance Metrics. 33g36.7 Device-b
22、ased Complexity Evaluation 33g36.7.1 Introduction. 33g3ETSI ETSI TR 126 947 V15.0.0 (2018-07)43GPP TR 26.947 version 15.0.0 Release 156.7.2 Test Cases . 33g36.7.3 Test Conditions 2 presented to TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is
23、 incremented for all changes of substance, i.e. technical enhancements, corrections, updates, etc. z the third digit is incremented when editorial only changes have been incorporated in the document. Introduction The on-going commercialization of LTE networks has precipitated increasing interest in
24、the deployment of eMBMS. As the industry is considering the first deployments of eMBMS it is important to enhance the performance and usability of its core features. After development of the initial MBMS specifications, SA4 has focused its subsequent work on adding new features to the service. While
25、 application layer FEC usage in support of download and streaming delivery methods have been specified since Rel-6, those mechanisms have not been updated to reflect performance improvement developments in more recent years. Examples of ongoing FEC enhancement efforts are the latest activities in IE
26、TFs RMT and FECFRAME working groups. Such FEC improvements can also provide more efficient support of MBMS use cases. The objective of this TR is to document the progress of the work item to investigate and evaluate proposed FEC technologies and, if appropriate, adopt one which provides the most sig
27、nificant enhancement to the performance of the MBMS system over the Rel-6 application layer FEC in MBMS. Aspects of system performance, which would provide benefit to the system, include, but are not limited to - Improving the bandwidth efficiency of streaming and download services delivery over MBM
28、S - Improving the reliability of streaming and download services delivery over MBMS, e.g. by increasing the amount of tolerable lost packets for a given FEC overhead - Reducing the required computational and memory resources for decoding in UEs - Addressing backward compatibility issues by consideri
29、ng deployments of pre-Rel-11 MBMS FEC The evaluation and selection process for the proposed improvements is documented in this TR. This Technical report contains the following attachments: - Attachment-1-Tools.zip: This attachment contains relevant tools for the purpose of setting up the evaluation
30、framework. - Attachment-2-Benchmark-Codes.xls: This attachment contains all relevant results for the benchmark codes - Attachment-3-Submission.zip: This attachment contains all submitted code overhead and device-evaluation results of the candidates ETSI ETSI TR 126 947 V15.0.0 (2018-07)73GPP TR 26.9
31、47 version 15.0.0 Release 15- Attachment-4-Verification.zip: This attachment contains all verification results for device-based evaluation. - Attachment-5-6330.zip: This attachment contains the proposed application of 6330 as MBMS application layer FEC as provided by the proponent. - Attachment-6-RS
32、+LDPC.zip: This attachment contains the proposed application of RS+LDPC as MBMS application layer FEC as provided by the proponent. ETSI ETSI TR 126 947 V15.0.0 (2018-07)83GPP TR 26.947 version 15.0.0 Release 151 Scope The present document documents the progress of the work item to investigate and e
33、valuate proposed FEC technologies and adopt one which provides the most significant enhancement to the performance of the MBMS system over the Release 6 application layer FEC in MBMS. 2 References The following documents contain provisions which, through reference in this text, constitute provisions
34、 of the present document. - References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. - For a specific reference, subsequent revisions do not apply. - For a non-specific reference, the latest version applies. In the case of a reference
35、to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document. 1 3GPP TR 21.905: “Vocabulary for 3GPP Specifications“. 2 3GPP TS 22.146: “Multimedia Broadcast/Multicast Service (MBMS); Stag
36、e 1“. 3 3GPP TS 26.346: “Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs“. 4 IETF RFC 3926 (October 2004): “FLUTE - File Delivery over Unidirectional Transport“, T. Paila, M. Luby, R. Lehtonen, V. Roca and R. Walsh. 5 IETF RFC 5053 (February 2004): “Raptor Forward Error Correctio
37、n Scheme for Object Delivery“, M. Luby, M.Watson, A. Shokrollahi, and T. Stockhammer. 6 IETF RFC 6363, “Forward Error Correction (FEC) Framework,“ M.Watson, A. Begen and V. Roca, October 2011. 7 3GPP TR 36.942, “Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Frequency (RF) system scenari
38、os.“ 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the terms and definitions given in TR 21.905 1 and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 1. Multim
39、edia Broadcast/Multicast Service (MBMS): See 3GPP TS 22.146 2. MBMS user services: See 3GPP TS 22.146 2. MBMS delivery method: mechanism used by a MBMS user service to deliver content There are two MBMS delivery method instances: download and streaming. MBMS download delivery method: delivery of dis
40、crete objects (e.g. files) by means of a MBMS download session MBMS streaming delivery method: delivery of continuous media (e.g. real-time video) by means of a MBMS streaming session MBMS download session: time, protocols and protocol state (i.e. parameters) which define sender and receiver configu
41、ration for the download of content files MBMS streaming session: time, protocols and protocol state (i.e. parameters) which define sender and receiver configuration for the streaming of content ETSI ETSI TR 126 947 V15.0.0 (2018-07)93GPP TR 26.947 version 15.0.0 Release 153.2 Abbreviations For the p
42、urposes of the present document, the abbreviations given in TR 21.905 1 and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 1. ALC Asynchronous Layered Coding BM-SC Broadcast-Multicast - Service
43、Centre ESI Encoding Symbol IDFDT File Delivery Table FEC Forward Error Correction FLUTE File deLivery over Unidirectional Transport IP Internet Protocol LCT Layered Coding Transport MBMS Multimedia Broadcast/Multicast Service PSS Packet Switch Streaming RTP Real-Time Transport Protocol SBN Source Bl
44、ock Number TOI Transport Object Identifier UDP User Datagram Protocol 4 Use of FEC in MBMS 4.1 Introduction Application Layer FEC is used in MBMS to compensate remaining losses on or below the IP layer in unidirectional delivery environments. 4.2 Architecture Figure 1 depicts the MBMS network archit
45、ecture showing MBMS related entities involved in providing MBMS user services as specified in TS 26.346 3 with special focus to the FEC component. The FEC is included in the MBMS User Services which are part of the BM-SC on the network side and MBMS receiver on the UE side. FEC is specifically inclu
46、ded in the File Delivery over Unidirectional Transport (FLUTE) 4 protocol and the Forward Error Correction (FEC) Framework (FECFRAME) 6 protocol. Figure 1: Overview on FEC operation in MBMS ETSI ETSI TR 126 947 V15.0.0 (2018-07)103GPP TR 26.947 version 15.0.0 Release 154.3 MBMS Bearer in UTRAN The M
47、BMS UTRAN Bearer service reuses most of the legacy UMTS protocol stack in the packet-switched domain. Only minor modifications are introduced to support MBMS. The IP packets are processed in the Packet Data Convergence Protocol (PDCP) layer where for example header compression might be applied. In t
48、he Radio Link Control (RLC) the resulting PDCP-Protocol Data Units (PDUs), generally of arbitrary length, are mapped to fixed length RLC-PDUs. The RLC layer operates in unacknowledged mode as feedback links on the radio access network are not available for point-to-multipoint bearers. Functions prov
49、ided at the RLC layer are for example segmentation and reassembly, concatenation, padding, sequence numbering, reordering and out-of-sequence and duplication detection. The Medium Access Control (MAC) layer maps and multiplexes the RLC-PDUs to the transport channel and selects the transport format depending on the instantaneous source rate. The MAC layer and physical layer appropriately adapt the RLC-PDU to the expected transmission conditions by applying, among others, channel coding, power and resource assignment, and modulation. 4.4 MBMS Be
