1、 ETSI TS 136 420 V15.0.0 (2018-07) LTE; Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 general aspects and principles (3GPP TS 36.420 version 15.0.0 Release 15) TECHNICAL SPECIFICATION ETSI ETSI TS 136 420 V15.0.0 (2018-07)13GPP TS 36.420 version 15.0.0 Release 15Reference RTS/TSGR
2、-0336420vf00 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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9、se 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 publicly available for ETSI members and non-members, and can be found in ETSI SR 000 31
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13、resent document does not constitute an endorsement by ETSI of products, services or organizations associated with those trademarks. Foreword This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP). The present document may refer to technical specificatio
14、ns 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 identities can be found under http:/webapp.etsi.org/key/queryform.asp. Modal verb
15、s terminology In the present document “shall“, “shall not“, “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 expression of provisions). “must“ and “must not“ are NOT all
16、owed in ETSI deliverables except when used in direct citation. ETSI ETSI TS 136 420 V15.0.0 (2018-07)33GPP TS 36.420 version 15.0.0 Release 15Contents Intellectual Property Rights 2g3Foreword . 2g3Modal verbs terminology 2g3Foreword . 5g31 Scope. . 6g32 References 6g33 Definitions, symbols and abbre
17、viations . 6g33.1 Definitions 6g33.2 Abbreviations . 7g34 General aspects . 7g34.1 Introduction 7g34.2 X2 interface general principles . 7g34.3 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
18、 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 Functions 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
19、.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 9g35.2.1.3 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 interf
20、erence coordination . 9g35.2.3.1 Uplink interference load management 9g35.2.3.2 Downlink interference avoidance 9g35.2.4 General X2 management and error handling functions 9g35.2.4.1 Error indication . 10g35.2.4.2 Reset 10g35.2.5 Trace functions . 10g35.2.6 Application level data exchange between eN
21、Bs . 10g35.2.7 Data exchange for self-optimisation . 10g36 X2 interface protocols and protocol structure 10g36.1 General . 10g36.2 Radio signalling protocols 10g36.2.1 X2AP protocol 10g36.3 User plane protocol 11g36.3.1 Tunnelling protocol GTP-U 11g36.4 X2 interface protocol structure . 11g37 Other
22、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 36.422) . 11g37.3 E-UTRAN X2 interface: X2 application protocol (X2AP) (TS 36.423) 11g37.4 E-UTRAN X2 interface: X2 data transport (TS 36.424) 11g3ETSI ETSI TS
23、 136 420 V15.0.0 (2018-07)43GPP TS 36.420 version 15.0.0 Release 157.5 Summary of E-UTRAN X2 interface Technical Specifications . 12g3Annex A (informative): Change history . 13g3History 14g3ETSI ETSI TS 136 420 V15.0.0 (2018-07)53GPP TS 36.420 version 15.0.0 Release 15Foreword This Technical Specifi
24、cation has been produced by the 3rdGeneration Partnership Project (3GPP). The contents of the present document are subject to continuing work 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 wit
25、h 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 TSG 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
26、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. ETSI ETSI TS 136 420 V15.0.0 (2018-07)63GPP TS 36.420 version 15.0.0 Release 151 Scope. The present document is an in
27、troduction to the TSG RAN TS 36.42x series of UMTS Technical Specifications that define the X2 interface. It is an interface for the interconnection of two E-UTRAN NodeB (eNB) components within the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) architecture (TS 36.401 2). 2 References
28、The following 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 revision
29、s 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 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: “Voca
30、bulary for 3GPP Specifications”. 2 3GPP TS 36.401: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Architecture description”. 3 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 Net
31、work (E-UTRAN); X2 signaling transport”. 5 3GPP TS 36.423: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 application protocol (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 T
32、ransmission Protocol”. 8 3GPP TS 36.300: “Evolved Universal Terrestrial Radio Access (E-UTRA), Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2”. 3 Definitions, symbols and abbreviations 3.1 Definitions For the purposes of the present document, the terms and
33、 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. 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 4
34、20 V15.0.0 (2018-07)73GPP TS 36.420 version 15.0.0 Release 153.2 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 a
35、ny, 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 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 inter
36、face general principles The general principles for the specification of the X2 interface are as follows: - the X2 interface should be open; - 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
37、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-point logical interface should be feasible even in the absence of a physical direct connection between the two eNBs. 4.3 X2 interface specification objective
38、s 4.3.1 General The X2 interface specifications shall facilitate the following: - inter-connection of eNBs supplied by different manufacturers; - support of continuation between eNBs of the E-UTRAN services offered via the S1 interface; - separation of X2 interface Radio Network functionality and Tr
39、ansport Network functionality to facilitate introduction of future technology. 4.3.2 Addressing of eNBs over the X2 interface - 4.4 X2 interface capabilities 4.4.1 Radio application related signalling The X2 interface provides capability to support radio interface mobility and Dual Connectivity betw
40、een eNBs, of Ues having a connection with E-UTRAN. ETSI ETSI TS 136 420 V15.0.0 (2018-07)83GPP TS 36.420 version 15.0.0 Release 154.4.2 X2 tunnels 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
41、 (X2AP) signalling messages between two eNBs A single SCTP association per X2-C interface instance shall be used, except when the X2 GW is used. 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 carrie
42、d 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 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 id
43、entifiers should be used for X2-C dedicated procedures. Source-eNB communication context identifiers that are assigned by the source-eNB for X2-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
44、 distinguish UE specific X2-C signalling transport bearers. The communication context identifiers are conveyed in the respective X2AP messages. 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
45、 ECM-CONNECTED UE: - Context transfer from source eNB to target eNB; - Control of user plane transport bearers between source eNB and target eNB; - Handover cancellation; - UE context release in source eNB; - Dual Connectivity. - Load Management - Inter-cell Interference Coordination - Uplink Interf
46、erence Load Management; - Downlink interference avoidance. - General X2 management and error handling functions: - Error indication; - Reset. - Application level data exchange between eNBs - Trace functions - Data exchange for self-optimisation ETSI ETSI TS 136 420 V15.0.0 (2018-07)93GPP TS 36.420 v
47、ersion 15.0.0 Release 155.2 Function description 5.2.1 Intra LTE-Access-System mobility support for ECM-CONNECTED UE This function allows the 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 informati
48、on 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 bearers between source eNB and target eNB This function allows establishing and releasing transport bearers between source and target eNB to allow for data forwa
49、rding. 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 from 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 eNB that a prepared handover will not take place. It allows releasing the resources allocated during a prepar
