1、 ETSI TS 136 420 V14.0.1 (2017-04) LTE; Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 general aspects and principles (3GPP TS 36.420 version 14.0.1 Release 14) TECHNICAL SPECIFICATION ETSI ETSI TS 136 420 V14.0.1 (2017-04)13GPP TS 36.420 version 14.0.1 Release 14Reference RTS/TSGR
2、-0336420ve01 Keywords LTE 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 enregistre la Sous-Prfecture de Grasse (06) N 7803/88 Important notice The present document
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7、without the written authorization of ETSI. The copyright and the foregoing restriction extend to reproduction in all media. European Telecommunications Standards Institute 2017. All rights reserved. DECTTM, PLUGTESTSTM, UMTSTMand the ETSI logo are Trade Marks of ETSI registered for the benefit of it
8、s Members. 3GPPTM and LTE are Trade Marks of ETSI registered for the benefit of its Members and of the 3GPP Organizational Partners. oneM2M logo is protected for the benefit of its Members GSM and the GSM logo are Trade Marks registered and owned by the GSM Association. ETSI ETSI TS 136 420 V14.0.1
9、(2017-04)23GPP TS 36.420 version 14.0.1 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 members and non-members, and can b
10、e 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.etsi.org/). Pursuant to the ETSI I
11、PR 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 the present document. Foreword Th
12、is Technical Specification (TS) 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 references to the correspond
13、ing 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 “shall“, “shall not“, “should“, “should not“, “may“, “need not“, “will“, “will not“, “can“ and “cannot“ a
14、re 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 TS 136 420 V14.0.1 (2017-04)33GPP TS 36.420 version 14.0.1 Release 14C
15、ontents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 5g31 Scope. . 6g32 References 6g33 Definitions, symbols and abbreviations . 6g33.1 Definitions 6g33.2 Abbreviations . 7g34 General aspects . 7g34.1 Introduction 7g34.2 X2 interface general principles . 7g34.3
16、 X2 interface specification objectives 7g34.3.1 General 7g34.3.2 Addressing of eNBs over the X2 interface . 7g34.4 X2 interface capabilities . 7g34.4.1 Radio application related signalling 7g34.4.2 X2 tunnels . 8g34.5 X2 interface characteristics 8g34.5.1 Uses of SCTP 8g34.5.1.1 General 8g35 Functio
17、ns of the X2 interface . 8g35.1 Function list 8g35.2 Function description . 9g35.2.1 Intra LTE-Access-System mobility support for ECM-CONNECTED UE . 9g35.2.1.1 Context transfer from source eNB to target eNB 9g35.2.1.2 Control of user plane transport bearers between source eNB and target eNB 9g35.2.1
18、.3 Handover cancellation . 9g35.2.1.4 UE context release in source eNB . 9g35.2.1.5 Dual Connectivity . 9g35.2.2 Load management . 9g35.2.3 Inter-cell interference coordination . 9g35.2.3.1 Uplink interference load management 9g35.2.3.2 Downlink interference avoidance 9g35.2.4 General X2 management
19、and error handling functions 10g35.2.4.1 Error indication . 10g35.2.4.2 Reset 10g35.2.5 Trace functions . 10g35.2.6 Application level data exchange between eNBs . 10g35.2.7 Data exchange for self-optimisation . 10g36 X2 interface protocols and protocol structure 10g36.1 General . 10g36.2 Radio signa
20、lling protocols 11g36.2.1 X2AP protocol 11g36.3 User plane protocol 11g36.3.1 Tunnelling protocol GTP-U 11g36.4 X2 interface protocol structure . 11g37 Other X2 interface specifications . 11g37.1 E-UTRAN X2 interface: X2 layer 1 (TS 36.421). 11g37.2 E-UTRAN X2 interface: X2 signaling transport (TS 3
21、6.422) . 12g37.3 E-UTRAN X2 interface: X2 application protocol (X2AP) (TS 36.423) 12g37.4 E-UTRAN X2 interface: X2 data transport (TS 36.424) 12g3ETSI ETSI TS 136 420 V14.0.1 (2017-04)43GPP TS 36.420 version 14.0.1 Release 147.5 Summary of E-UTRAN X2 interface Technical Specifications . 12g3Annex A
22、(informative): Change history . 13g3History 14g3ETSI ETSI TS 136 420 V14.0.1 (2017-04)53GPP TS 36.420 version 14.0.1 Release 14Foreword This Technical Specification has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work
23、within the TSG and may change following formal TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an identifying change of release date and an increase in version number as follows: Version x.y.z where: x the first digit: 1 presented to T
24、SG for information; 2 presented to 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
25、 have been incorporated in the document. ETSI ETSI TS 136 420 V14.0.1 (2017-04)63GPP TS 36.420 version 14.0.1 Release 141 Scope. The present document is an introduction to the TSG RAN TS 36.42x series of UMTS Technical Specifications that define the X2 interface. It is an interface for the interconn
26、ection of two E-UTRAN NodeB (eNB) components within the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) architecture (TS 36.401 2). 2 References The following documents contain provisions which, through reference in this text, constitute provisions of the present document. - References
27、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 to a 3GPP document (including a GSM doc
28、ument), 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 36.401: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Architecture description”. 3
29、 3GPP TS 36.421: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 layer 1”. 4 3GPP TS 36.422: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 signaling transport”. 5 3GPP TS 36.423: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 application proto
30、col (X2AP)”. 6 3GPP TS 36.424: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 data transport”. 7 IETF RFC 4960 (2007-09): “Stream Control Transmission Protocol”. 8 3GPP TS 36.300: “Evolved Universal Terrestrial Radio Access (E-UTRA), Evolved Universal Terrestrial Radio Access Netw
31、ork (E-UTRAN); Overall description; Stage 2”. 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
32、same term, if any, in TR 21.905 1. Dual Connectivity: Defined in TS 36.300 8. E-RAB: Defined in TS 36.401 2. X2 GW: Defined in TS 36.300 8. ETSI ETSI TS 136 420 V14.0.1 (2017-04)73GPP TS 36.420 version 14.0.1 Release 143.2 Abbreviations For the purposes of the present document, the abbreviations giv
33、en 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. ECM EPS Connection Management E-RAB E-UTRAN Radio Access Bearer MeNB Master eNB SeNB Secondary eNBX2-C X2 Control plane X2
34、 GW X2 GateWay 4 General aspects 4.1 Introduction The interface allowing to interconnect eNBs with each other is referred to as the X2 interface. 4.2 X2 interface general principles The general principles for the specification of the X2 interface are as follows: - the X2 interface should be open; -
35、the X2 interface shall support the exchange of signalling information between two eNBs, in addition the interface shall support the forwarding of PDUs to the respective tunnel endpoints; - from a logical standpoint, the X2 is a point-to-point interface between two eNBs within the E-UTRAN. A point-to
36、-point logical interface should be feasible even in the absence of a physical direct connection between the two eNBs. 4.3 X2 interface specification objectives 4.3.1 General The X2 interface specifications shall facilitate the following: - inter-connection of eNBs supplied by different manufacturers
37、; - support of continuation between eNBs of the E-UTRAN services offered via the S1 interface; - separation of X2 interface Radio Network functionality and Transport Network functionality to facilitate introduction of future technology. 4.3.2 Addressing of eNBs over the X2 interface - 4.4 X2 interfa
38、ce capabilities 4.4.1 Radio application related signalling The X2 interface provides capability to support radio interface mobility and Dual Connectivity between eNBs, of Ues having a connection with E-UTRAN. ETSI ETSI TS 136 420 V14.0.1 (2017-04)83GPP TS 36.420 version 14.0.1 Release 144.4.2 X2 tun
39、nels 4.5 X2 interface characteristics 4.5.1 Uses of SCTP 4.5.1.1 General The SCTP (IETF RFC 4960 7) is used to support the exchange of X2 Application Protocol (X2AP) signalling messages between two eNBs A single SCTP association per X2-C interface instance shall be used, except when the X2 GW is use
40、d. Only when the X2 GW is used to connect one eNB to one or more specific eNB(s), all X2-C interface instances from that eNB to the relevant eNB(s) are carried over the same SCTP association from that eNB to the X2 GW, and over separate SCTP association(s) from the X2 GW to the relevant eNB(s). For
41、X2-C interface instance(s) over one SCTP association one pair of stream identifiers shall be used for X2-C common procedures and only a few pairs of stream identifiers should be used for X2-C dedicated procedures. Source-eNB communication context identifiers that are assigned by the source-eNB for X
42、2-C dedicated procedures, and target-eNB communication context identifiers that are assigned by the target-eNB for X2-C dedicated procedures, shall be used to distinguish UE specific X2-C signalling transport bearers. The communication context identifiers are conveyed in the respective X2AP messages
43、. 5 Functions of the X2 interface 5.1 Function list The list of functions on the X2 interface is the following: - Intra LTE-Access-System Mobility Support for ECM-CONNECTED UE: - Context transfer from source eNB to target eNB; - Control of user plane transport bearers between source eNB and target e
44、NB; - Handover cancellation; - UE context release in source eNB; - Dual Connectivity. - Load Management - Inter-cell Interference Coordination - Uplink Interference Load Management; - Downlink interference avoidance. - General X2 management and error handling functions: - Error indication; - Reset.
45、- Application level data exchange between eNBs - Trace functions ETSI ETSI TS 136 420 V14.0.1 (2017-04)93GPP TS 36.420 version 14.0.1 Release 14- Data exchange for self-optimisation 5.2 Function description 5.2.1 Intra LTE-Access-System mobility support for ECM-CONNECTED UE This function allows the
46、eNB to handover the control of a certain UE to another eNB. 5.2.1.1 Context transfer from source eNB to target eNB This function allows transferring information required to maintain the E-UTRAN services for an UE in ECM-CONNECTED from source to target eNB. 5.2.1.2 Control of user plane transport bea
47、rers between source eNB and target eNB This function allows establishing and releasing transport bearers between source and target eNB to allow for data forwarding. At most one user plane transport bearer per E-RAB allocated to the UE may be established for relaying DL data received from the EPC fro
48、m the source eNB to the target eNB. At most one user plane transport bearer per E-RAB allocated to the UE may be established for relaying the UL data received from the UE from the source eNB to the target eNB. 5.2.1.3 Handover cancellation This function allows informing an already prepared target eN
49、B that a prepared handover will not take place. It allows releasing the resources allocated during a preparation. 5.2.1.4 UE context release in source eNB This function allows the target eNB to trigger the release of the resources allocated to the UE in the source eNB. 5.2.1.5 Dual Connectivity This function allows MeNB and SeNB to support Dual Connectivity. MeNB and SeNB manage establishment, modification and release of UE context at the SeNB, and controls user plane tunnels over X2. 5.2.2 Load management This function allows exchanging over
