1、 ETSI TR 126 947 V14.0.0 (2017-04) 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 14.0.0 Release 14) floppy3TECHNICAL REPORT ETSI ETSI TR
2、 126 947 V14.0.0 (2017-04)13GPP TR 26.947 version 14.0.0 Release 14Reference RTR/TSGS-0426947ve00 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 en
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9、ion. ETSI ETSI TR 126 947 V14.0.0 (2017-04)23GPP TR 26.947 version 14.0.0 Release 14Intellectual Property Rights IPRs essential or potentially essential to the present document may have been declared to ETSI. The information pertaining to these essential IPRs, if any, is publicly available for ETSI
10、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 Web server (https:/ipr.
11、etsi.org/). Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web server) which are, or may be, or may become, essential to
12、 the present document. Foreword This Technical Report (TR) has been produced by ETSI 3rd Generation Partnership 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 r
13、eferences to the corresponding ETSI deliverables. The cross reference between GSM, UMTS, 3GPP and ETSI identities 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 “cann
14、ot“ are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of provisions). “must“ and “must not“ are NOT allowed in ETSI deliverables except when used in direct citation. ETSI ETSI TR 126 947 V14.0.0 (2017-04)33GPP TR 26.947 version 14.0.0 Releas
15、e 14Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 6g3Introduction 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 M
16、BMS Bearer in UTRAN . 10g34.4 MBMS Bearer in E-UTRAN 10g34.5 Streaming Delivery User Service . 10g34.5.1 Introduction. 10g34.5.2 Transport in streaming delivery service 11g34.5.3 Examples 12g34.6 Download Delivery User Service . 12g34.6.1 Introduction. 12g34.6.2 Transport in download delivery servic
17、e 12g34.6.3 Download Examples . 13g34.7 Streaming using DASH and Download Delivery User Service 13g35 MBMS Bearer Service Channel Modelling . 14g35.1 Introduction 14g35.2 Modelling of UTRAN MBMS Bearer 14g35.3 Modelling of E-UTRAN MBMS Bearer 14g36 FEC Evaluation Procedure . 18g36.1 Introduction 18g
18、36.2 Simulation Conditions 18g36.2.1 Simulation conditions and assumptions (UTRAN). 18g36.2.2 Simulation conditions and assumptions (LTE eMBMS) 19g36.3 Code Performance 20g36.3.1 Introduction. 20g36.3.2 Method 1 . 20g36.3.2.1 Evaluation Procedure 20g36.3.2.2 Test Cases . 22g36.3.2.3 Performance Metr
19、ics . 22g36.3.3 Method 2 . 23g36.3.3.1 Evaluation Procedure 23g36.3.3.2 Test Cases . 23g36.3.3.3 Performance Metrics . 24g36.4 Download Performance 25g36.4.1 Performance Metrics. 25g36.4.2 Download Performance over UTRAN 25g36.4.3 Download Performance over LTE 26g36.5 UTRAN Streaming Performance . 2
20、9g36.6 Streaming Performance over LTE 30g36.6a Implementation-specific Performance Metrics. 34g36.7 Device-based Complexity Evaluation 34g36.7.1 Introduction. 34g3ETSI ETSI TR 126 947 V14.0.0 (2017-04)43GPP TR 26.947 version 14.0.0 Release 146.7.2 Test Cases . 34g36.7.3 Test Conditions 2 presented t
21、o TSG for approval; 3 or greater indicates TSG approved document under change control. y the second digit is 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 do
22、cument. Introduction The on-going commercialization of LTE networks has precipitated increasing interest in 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 i
23、nitial MBMS specifications, SA4 has focused its subsequent work on adding new features to the service. While 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 de
24、velopments in more recent years. Examples of ongoing FEC enhancement efforts are the latest activities in IETFs 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 i
25、nvestigate and evaluate proposed FEC technologies and, if appropriate, adopt one which provides the most significant 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
26、are not limited to Improving the bandwidth efficiency of streaming and download services delivery over MBMS 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 computat
27、ional and memory resources for decoding in UEs Addressing backward compatibility issues by considering 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-
28、1-Tools.zip: This attachment contains relevant tools for the purpose of setting up the evaluation 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 d
29、evice-evaluation results of the candidates ETSI ETSI TR 126 947 V14.0.0 (2017-04)73GPP TR 26.947 version 14.0.0 Release 14 Attachment-4-Verification.zip: This attachment contains all verification results for device-based evaluation. Attachment-5-6330.zip: This attachment contains the proposed applic
30、ation of 6330 as MBMS application layer FEC as provided by the proponent. Attachment-6-RS+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 V14.0.0 (2017-04)83GPP TR 26.947 version 14.0.0 Release 14
31、1 Scope The present document documents the progress of the work item to investigate and evaluate 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
32、documents contain provisions which, through reference in this text, constitute provisions 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
33、. - For a non-specific reference, the latest version applies. In the case of a reference 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 3GP
34、P Specifications“. 2 3GPP TS 22.146: “Multimedia Broadcast/Multicast Service (MBMS); Stage 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. Lehtone
35、n, V. Roca and R. Walsh. 5 IETF RFC 5053 (February 2004): “Raptor Forward Error Correction 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,
36、“Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Frequency (RF) system scenarios.“ 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 docum
37、ent takes precedence over the definition of the same term, if any, in TR 21.905 1. Multimedia 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
38、 method instances: download and streaming. MBMS download delivery method: delivery of discrete 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
39、, protocols and protocol state (i.e. parameters) which define sender and receiver configuration for the download of content files ETSI ETSI TR 126 947 V14.0.0 (2017-04)93GPP TR 26.947 version 14.0.0 Release 14MBMS streaming session: time, protocols and protocol state (i.e. parameters) which define s
40、ender and receiver configuration for the streaming of content 3.2 Abbreviations For the purposes 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
41、any, in TR 21.905 1. ALC Asynchronous Layered Coding BM-SC Broadcast-Multicast - Service 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/Mul
42、ticast Service PSS Packet Switch Streaming RTP Real-Time Transport Protocol SBN Source Block 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 unidir
43、ectional delivery environments. 4.2 Architecture Figure 1 depicts the MBMS network architecture 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
44、the BM-SC on the network side and MBMS receiver on the UE side. FEC is specifically included in the File Delivery over Unidirectional Transport (FLUTE) 4 protocol and the Forward Error Correction (FEC) Framework (FECFRAME) 6 protocol. ETSI ETSI TR 126 947 V14.0.0 (2017-04)103GPP TR 26.947 version 14
45、.0.0 Release 14Figure 1: Overview on FEC operation in MBMS 4.3 MBMS Bearer in UTRAN The MBMS 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 Conv
46、ergence Protocol (PDCP) layer where for example header compression might be applied. In the 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 t
47、he radio access network are not available for point-to-multipoint bearers. Functions provided 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
48、 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 a
49、ssignment, and modulation. 4.4 MBMS Bearer in E-UTRAN The MBMS E-UTRAN Bearer service reuses most of the legacy LTE 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 the 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 u
