ETSI TS 136 401 V16.0.0 (2020-07)

ETSI TS 136 401 V16.0.0 (2020-07)
TECHNICAL SPECIFICATION
LTE;
Evolved Universal Terrestrial
Radio Access Network (E-UTRAN);
Architecture description
(3GPP TS 36.401 version 16.0.0 Release 16)
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3GPP TS 36.401 version 16.0.0 Release 16 1 ETSI TS 136 401 V16.0.0 (2020-07)
Reference
RTS/TSGR-0336401vg00
Keywords
LTE
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Intellectual Property Rights ................................................................................................................................ 2

Legal Notice ....................................................................................................................................................... 2

Modal verbs terminology .................................................................................................................................... 2

Foreword ............................................................................................................................................................. 5

1 Scope ........................................................................................................................................................ 6

2 References ................................................................................................................................................ 6

3 Definitions and abbreviations ................................................................................................................... 7

3.1 Definitions .......................................................................................................................................................... 7

3.2 Abbreviations ..................................................................................................................................................... 7

4 General principles .................................................................................................................................... 8

5 General architecture ................................................................................................................................. 9

5.1 General ............................................................................................................................................................... 9

5.2 User plane ........................................................................................................................................................... 9

5.3 Control plane ...................................................................................................................................................... 9

6 E-UTRAN architecture........................................................................................................................... 10

6.1 Overview .......................................................................................................................................................... 10

6.2 E-UTRAN identifiers ....................................................................................................................................... 11

6.2.1 Principle of handling Application Protocol Identities ................................................................................. 11

6.2.2 PLMN Identity ............................................................................................................................................ 12

6.2.3 Globally Unique MME Identifier (GUMMEI) ........................................................................................... 12

6.2.4 Global eNB ID ............................................................................................................................................ 12

6.2.5 E-UTRAN Cell Global Identifier (ECGI) ................................................................................................... 13

6.2.6 Tracking Area Identity ................................................................................................................................ 13

6.2.7 E-RAB ID ................................................................................................................................................... 13

6.2.8 UE Identifiers .............................................................................................................................................. 13

6.2.8.1 Radio Network Temporary Identifiers (RNTI) ..................................................................................... 13

6.2.8.2 S-Temporary Mobile Subscriber Identity (S-TMSI) ............................................................................. 13

6.3 Transport addresses .......................................................................................................................................... 13

6.4 UE associations in eNB .................................................................................................................................... 13

7 E-UTRAN functions description ............................................................................................... ............. 14

7.1 List of functions ............................................................................................................................................... 14

7.2 Functions description ....................................................................................................................................... 15

7.2.1 Transfer of user data ................................................................................................................................... 15

7.2.2 Radio channel ciphering and deciphering ................................................................................................... 15

7.2.3 Integrity protection ..................................................................................................................................... 15

7.2.4 Header compression .................................................................................................................................... 15

7.2.5 Mobility control functions .......................................................................................................................... 15

7.2.5.1 Handover ............................................................................................................................................... 15

7.2.5.2 void ....................................................................................................................................................... 15

7.2.5.3 void ....................................................................................................................................................... 15

7.2.5.4 Dual Connectivity ................................................................................................................................. 15

7.2.6 Inter-cell interference coordination ............................................................................................................. 15

7.2.7 Connection set-up and release .................................................................................................................... 16

7.2.8 Load balancing ............................................................................................................................................ 16

7.2.9 Distribution function for NAS messages .................................................................................................... 16

7.2.10 NAS node selection function ...................................................................................................................... 16

7.2.11 Synchronization .......................................................................................................................................... 16

7.2.12 Radio Access Network (RAN) sharing ....................................................................................................... 16

7.2.13 MBMS function .......................................................................................................................................... 16

7.2.14 Subscriber and equipment trace .................................................................................................................. 17

7.2.15 RAN Information Management (RIM) ....................................................................................................... 17

7.2.16 Paging ......................................................................................................................................................... 17

7.2.17 Positioning .................................................................................................................................................. 17

7.2.18 Delivery of warning messages .................................................................................................................... 17

8 Mobility management............................................................................................................................. 17

8.1 Signalling connection ....................................................................................................................................... 17

8.2 Consequences for mobility handling ................................................................................................................ 18

9 Synchronization ...................................................................................................................................... 18

9.1 eNB Synchronization ....................................................................................................................................... 18

9.2 eNB and MME Synchronization ...................................................................................................................... 19

10 void ......................................................................................................................................................... 19

11 E-UTRAN interfaces .............................................................................................................................. 19

11.1 General protocol model for E-UTRAN interfaces ............................................................................................ 19

11.1.1 Radio Network Layer (RNL) and Transport Network Layer (TNL) .......................................................... 20

11.1.2 Control plane .............................................................................................................................................. 20

11.1.3 User plane ................................................................................................................................................... 20

11.2 Iuant interface - general principles ................................................................................................................... 20

Annex A (informative): Change history ............................................................................................... 21

History .............................................................................................................................................................. 22

This Technical Specification has been produced by the 3 Generation 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 with an

y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,

z the third digit is incremented when editorial only changes have been incorporated in the document.

The present document describes the overall architecture of the E-UTRAN, including internal interfaces and assumptions

The following documents contain provisions which, through reference in this text, constitute provisions of the present

- References are either specific (identified by date of publication, edition number, version number, etc.) or

- 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

[2] 3GPP TS 36.300: "Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal

[3] 3GPP TS 23.401: "General Packet Radio Service (GPRS) enhancements for Evolved Universal

[4] 3GPP TS 36.414: "Evolved Universal Terrestrial Access Network (E-UTRAN); S1 data transport".

[5] 3GPP TS 36.424: "Evolved Universal Terrestrial Access Network (E-UTRAN); X2 data

[6] 3GPP TS 36.440: "Evolved Universal Terrestrial Radio Access Network (E-UTRAN); General

aspects and principles for interfaces supporting Multimedia Broadcast Multicast Service (MBMS)

[7] ITU-T Recommendation G.823 (2000-03): "The control of jitter and wander within digital

[8] ITU-T Recommendation G.824 (2000-03): "The control of jitter and wander within digital

[9] ITU-T Recommendation G.825 (2001-08): "The control of jitter and wander within digital

[10] ITU-T Recommendation G.8261/Y.1361 (2008-04): "Timing and Synchronization aspects in

[13] 3GPP TS 48.018: "General Packet Radio Service (GPRS); Base Station System (BSS) - Serving

[16] 3GPP TS 33.401: "3GPP System Architecture Evolution (SAE); Security architecture".

[17] 3GPP TS 32.421: "Telecommunication management; Subscriber and equipment trace; Trace

[18] 3GPP TS 32.422: "Telecommunication management; Subscriber and equipment trace; Trace

[19] 3GPP TS 32.423: "Telecommunication management; Subscriber and equipment trace; Trace data

[20] 3GPP TS 32.441: "Telecommunication management; Trace Management Integration Reference

[21] 3GPP TS 32.442: "Telecommunication management; Trace Management Integration Reference

[22] 3GPP TS 32.446: "Telecommunication management; Trace Management Integration Reference

[24] 3GPP TS 23.682: "Architecture enhancements to facilitate communications with packet data

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].

E-RAB: An E-RAB uniquely identifies the concatenation of an S1 Bearer and the corresponding Data Radio Bearer.

When an E-RAB exists, there is a one-to-one mapping between this E-RAB and an EPS bearer of the Non Access

S1: logical interface between an eNB and an EPC, providing an interconnection point between the E-UTRAN and the

X2: logical interface between two eNBs. Whilst logically representing a point-to-point link between eNBs, the physical

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].

The general principles guiding the definition of E-UTRAN architecture as well as the E-UTRAN interfaces are the

- E-UTRAN and EPC functions are fully separated from transport functions. Addressing scheme used in

E-UTRAN and EPC shall not be tied to the addressing schemes of transport functions. The fact that some

E-UTRAN or EPC functions reside in the same equipment as some transport functions does not make the

● The functional division across the interfaces shall have as few options as possible;

● Interfaces should be based on a logical model of the entity controlled through this interface;

These are the protocols implementing the actual E-RAB service, i.e. carrying user data through the access

These are the protocols for controlling the E-RABs and the connection between the UE and the network from

different aspects (including requesting the service, controlling different transmission resources, handover etc.).

The E-RAB service is offered from SAP to SAP by the Access Stratum. Figure 5.2-1 shows the protocols on the Uu and

Note 1: The radio interface protocols are defined in 3GPP TS 36.2xx and TS 36.3xx.

Figure 5.3-1 shows the control plane (signalling) protocol stacks on S1 and Uu interfaces.

Note 1: The radio interface protocols are defined in 3GPP TS 36.2xx and TS 36.3xx.

Note 2: The protocol is defined in 3GPP TS 36.41x. (Description of S1 interface).

Note 3: EMM, ESM: This exemplifies a set of NAS control protocols between UE and EPC. The evolution of the

protocol architecture for these protocols is outside the scope of the present document.

NOTE: Both the Radio protocols and the S1 protocols contain a mechanism to transparently transfer NAS

The E-UTRAN is layered into a Radio Network Layer (RNL) and a Transport Network Layer (TNL).

The E-UTRAN architecture, i.e. the E-UTRAN logical nodes and interfaces between them, is defined as part of the

For each E-UTRAN interface (S1, X2) the related TNL protocol and the functionality are specified. The TNL provides

In S1-Flex configuration, each eNB is connected to all EPC nodes within a pool area. The pool area is defined in

If security protection for control plane and user plane data on TNL of E-UTRAN interfaces has to be supported,

An Application Protocol Identity (AP ID) is allocated when a new UE-associated logical connection is created in an

eNB, or an MME, or in a WT. An AP ID shall uniquely identify a logical connection associated to a UE over the S1

interface, or X2 interface, or Xw interface within a node (eNB, or MME, or WT). Upon receipt of a message that has a

new AP ID from the sending node, the receiving node shall store the AP ID of the sending node for the duration of the

logical connection. The receiving node shall assign the AP ID to be used to identify the logical connection associated to

the UE and include it as well as the previously received new AP ID from the sending node, in the first returned message

to the sending node. In all subsequent messages to and from sending node, both AP IDs of sending node and receiving

The definitions of AP IDs as used on S1 interface, or X2 interface, or Xw interface are shown below:

An eNB UE S1AP ID shall be allocated so as to uniquely identify the UE over the S1 interface within an eNB.

When an MME receives an eNB UE S1AP ID it shall store it for the duration of the UE-associated logical S1-

connection for this UE. Once known to an MME this is included in all UE associated S1-AP signalling.