ETSI TS 136 401 V8.5.0 (2009-04)

LTE; Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Architecture description (3GPP TS 36.401 version 8.5.0 Release 8)

RTS/TSGR-0336401v850

General Information

• Status: Published
• Publication Date: 13-Apr-2009
• Technical Committee: 3GPP RAN 3 - lub specification, lur specification, lu specification and UTRAN & O&M
• Current Stage: 12 - Completion
• Due Date: 03-Apr-2009
• Completion Date: 14-Apr-2009

Standards Content (Sample)

ETSI TS 136 401 V8.5.0 (2009-04)
Technical Specification


LTE;
Evolved Universal Terrestrial Radio
Access Network (E-UTRAN);
Architecture description
(3GPP TS 36.401 version 8.5.0 Release 8)

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3GPP TS 36.401 version 8.5.0 Release 8 1 ETSI TS 136 401 V8.5.0 (2009-04)



Reference
RTS/TSGR-0336401v850
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LTE
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3GPP TS 36.401 version 8.5.0 Release 8 2 ETSI TS 136 401 V8.5.0 (2009-04)
Intellectual 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 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 (http://webapp.etsi.org/IPR/home.asp).
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 the present document.
Foreword
This 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 corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 3 ETSI TS 136 401 V8.5.0 (2009-04)
Contents
Intellectual Property Rights.2
Foreword.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 .8
5.1 General.8
5.2 User plane.8
5.3 Control plane.9
6 E-UTRAN architecture.10
6.1 Overview.10
6.2 E-UTRAN Identifiers.10
6.2.1 The principle of handling of Application Protocol Identities .10
6.2.2 PLMN Identity.11
6.2.3 Globally Unique MME Identifier (GUMMEI) .11
6.2.4 Global eNB ID.11
6.2.5 E-UTRAN Cell Global Identifier (ECGI).11
6.2.6 Tracking Area Identity.12
6.2.7 E-RAB ID .12
6.2.8 UE Identifiers.12
6.2.8.1 RNTI.12
6.2.8.2 S-Temporary Mobile Subscriber Identity (S-TMSI).12
6.3 Transport Addresses.12
6.4 UE associations in eNB.12
7 E-UTRAN functions description.13
7.1 List of functions .13
7.2 Functions description.13
7.2.1 Transfer of user data .13
7.2.2 Radio channel ciphering and deciphering.14
7.2.3 Integrity protection.14
7.2.4 Header compression.14
7.2.5 Mobility control functions .14
7.2.5.1 Handover.14
7.2.5.2 void.14
7.2.5.3 Positioning.14
7.2.6 Inter-cell interference coordination.14
7.2.7 Connection setup and release.14
7.2.8 Load balancing.14
7.2.9 Distribution function for NAS messages .15
7.2.10 NAS node selection function .15
7.2.11 Synchronization.15
7.2.12 Radio access network sharing.15
7.2.13 MBMS function.15
7.2.14 Subscriber and equipment trace.15
7.2.15 RAN Information Management .15
7.2.16 Paging.15
8 Mobility management.16
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 4 ETSI TS 136 401 V8.5.0 (2009-04)
8.1 Signalling connection.16
8.2 Consequences for mobility handling .16
9 Synchronization.16
9.1 eNB Synchronisation.16
10 void.17
11 E-UTRAN interfaces.17
11.1 General protocol model for E-UTRAN interfaces.17
11.1.1 Radio Network Layer and Transport Network Layer .17
11.1.2 Control plane.18
11.1.3 User plane.18
11.2 Iuant Interface - general principles.18
Annex A (informative): Change History .19
History .20

ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 5 ETSI TS 136 401 V8.5.0 (2009-04)
Foreword
rd
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
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 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

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3GPP TS 36.401 version 8.5.0 Release 8 6 ETSI TS 136 401 V8.5.0 (2009-04)
1 Scope
The present document describes the overall architecture of the E-UTRAN, including internal interfaces and
assumptions on the radio, S1 and X2 interfaces.
2 References
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 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 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 36.300: " Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal
Terrestrial Radio Access Network (E-UTRAN) Overall description Stage 2".
[3] 3GPP TS 23.401: " GPRS enhancements for E-UTRAN access".
[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
transport".
[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)
within E-UTRAN".
[7] ITU-T Recommendation G.823 (3/00): "The control of jitter and wander within digital networks
which are based on the 2048 kbit/s hierarchy".
[8] ITU-T Recommendation G.824 (3/00): "The control of jitter and wander within digital networks
which are based on the 1544 kbit/s hierarchy".
[9] ITU-T Recommendation G.825 (8/01): "The control of jitter and wander within digital networks
which are based on the synchronous digital hierarchy (SDH)".
[10] ITU-T Recommendation G.8261/Y.1361 (2/08): "Timing and Synchronization aspects in Packet
networks".
[11] 3GPP TS 23.003: "Numbering, addressing and identification".
[12] 3GPP TR 44.901: "External Network Assisted Cell Change".
[13] 3GPP TS 48.018: "General Packet Radio Service (GPRS); BSS GPRS Protocol (BSSGP)".
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 7 ETSI TS 136 401 V8.5.0 (2009-04)
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
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
Stratum as defined in [3].
S1: interface between an eNB and an EPC, providing an interconnection point between the E-UTRAN and the EPC. It
is also considered as a reference point.
X2: logical interface between two eNBs. Whilst logically representing a point to point link between eNBs, the physical
realization need not be a point to point link.
3.2 Abbreviations
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].
AP Application Protocol
C-RNTI Cell RNTI
ECGI E-UTRAN Cell Global Identifier
EEC Ethernet Equipment Clock
eNB E-UTRAN Node B
E-RAB E-UTRAN Radio Access Bearer
EPC Evolved Packet Core
EPS Evolved Packet System
E-UTRA Evolved UTRA
E-UTRAN Evolved UTRAN
FDD Frequency Division Duplex
GUMMEI Globally Unique MME Identifier
ID Identity
IP Internet Protocol
LTE Long Term Evolution
MBMS Multimedia Broadcast Multicast Service
MBSFN Multimedia Broadcast multicast service Single Frequency Network
NDS Network Domain Security
MME Mobility Management Entity
NAS Non Access Stratum
PLMN Public Land Mobile Network
RA-RNTI Random Access RNTI
RET Remote Electrical Tilting
RIM RAN Information Management
RNL Radio Network Layer
RNTI Radio Network Temporary Identifier
RRC Radio Resource Control
RTP Real-time Transport Protocol
QoS Quality of Service
SFN System Frame Number
S-GW Serving Gateway
S-TMSI S-Temporary Mobile Subscriber Identity
TCP Transmission Control Protocol
TDD Time Division Duplex
TDM Time Division Multiplexing
TMA Tower Mounted Amplifier
TNL Transport Network Layer
UDP User Datagram Protocol
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 8 ETSI TS 136 401 V8.5.0 (2009-04)
UE User Equipment
UMTS Universal Mobile Telecommunication System
4 General principles
The general principles guiding the definition of E-UTRAN Architecture as well as the E-UTRAN interfaces are the
following:
- Logical separation of signalling and data transport networks.
- 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 transport
functions part of the E-UTRAN or the EPC.
- Mobility for RRC connection is fully controlled by the E-UTRAN.
- When defining the E-UTRAN interfaces the following principles were followed: 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.
- One physical network element can implement multiple logical nodes.
5 General architecture
5.1 General
The protocols over Uu and S1 interfaces are divided into two structures:
- User plane protocols
These are the protocols implementing the actual E-RAB service, i.e. carrying user data through the access
stratum.
- Control plane protocols
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.).
Also a mechanism for transparent transfer of NAS messages is included.
5.2 User plane
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
S1 interfaces that linked together provide this E-RAB service.
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 9 ETSI TS 136 401 V8.5.0 (2009-04)
Non-Access Stratum
Radio
Radio
S1 S1
proto-
proto- proto proto
cols
cols cols
cols
(1)
(1)
(2) (2)
Access Stratum
  EPC
UE
EUTRAN
Radio
S1
(Uu)

(1) The radio interface protocols are defined in documents TS 36.2xx and TS 36.3xx.
(2) The S1 interface protocols are defined in documents TS 36.41x.

Figure 5.2-1: S1 and Uu user plane
5.3 Control plane
Figure 5.3-1 shows the control plane (signalling) protocol stacks on S1 and Uu interfaces.
(3)
EMM,ESM EMM,ESM(3)
Non-Access Stratum
S1 S1
Radio
Radio
proto-
proto- proto proto
cols
cols cols
cols
(1)
(2)
(1) (2)
Access Stratum
  EPC
UE
EUTRAN
Radio
S1
(Uu)

(1) The radio interface protocols are defined in documents TS 36.2xx and TS 36.3xx.
(2) The protocol is defined in documents TS 36.41x. (Description of S1 interface).
(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.

Figure 5.3-1: S1 and Uu control plane
NOTE: Both the Radio protocols and the S1 protocols contain a mechanism to transparently transfer NAS
messages.
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 10 ETSI TS 136 401 V8.5.0 (2009-04)
6 E-UTRAN architecture
6.1 Overview

EPC
S1 S1
X2
EUTRAN
eNB eNB

Figure 6.1-1 Overall architecture
The LTE architecture can be further described as follow:
The E-UTRAN consists of set of eNBs connected to the EPC through the S1.
An eNB can support FDD mode, TDD mode or dual mode operation.
eNBs can be interconnected through the X2.
S1 and X2 are logical interfaces.
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
Radio Network Layer.
For each E-UTRAN interface (S1, X2) the related transport network layer protocol and functionality is specified. The
transport network layer provides services for user plane transport, signalling transport.
In S1-Flex configuration, each eNB is connected to all EPC nodes within a pool area. The pool area is defined in [3].
If Security protection for control plane and user plane data on transport network layer of E-UTRAN interfaces has to be
supported, NDS/IP [33.210 and (TS successor of) 33.821] shall be applied.
The eMBMS architecture is defined as in TS 36.440[6].
6.2 E-UTRAN Identifiers
This subclause shows those identifiers that are used in E-UTRAN.
6.2.1 The principle of handling of Application Protocol Identities
An Application Protocol Identity (AP ID) is allocated when a new UE-associated logical connection is created in either
an eNB or an MME. An AP ID shall uniquely identify a logical connection associated to a UE over the S1 interface or
X2 interface within a node (eNB or MME). 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 node shall be included.
The definitions of AP IDs as used on S1 interface or X2 interface are shown below:
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 11 ETSI TS 136 401 V8.5.0 (2009-04)
eNB UE S1AP ID:
A 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 IE is included in all UE associated S1-AP signalling. The
eNB UE S1AP ID shall be unique within the eNB logical node.
MME UE S1AP ID:
A MME UE S1AP ID shall be allocated so as to uniquely identify the UE over the S1 interface within the MME.
When an eNB receives MME UE S1AP ID it shall store it for the duration of the UE-associated logical S1-
connection for this UE. Once known to an eNB this IE is included in all UE associated S1-AP signalling. The
MME UE S1AP ID shall be unique within the MME logical node.
Old eNB UE X2AP ID:
An Old eNB UE X2AP ID shall be allocated so as to uniquely identify the UE over the X2 interface within a
source eNB. When a target eNB receives an Old eNB UE X2AP ID it shall store it for the duration of the UE-
associated logical X2-connection for this UE. Once known to a target eNB this IE is included in all UE
associated X2-AP signalling. The Old eNB UE X2AP ID shall be unique within the eNB logical node.
New eNB UE X2AP ID:
An New eNB UE X2AP ID shall be allocated so as to uniquely identify the UE over the X2 interface within a
target eNB. When a source eNB receives a New eNB UE X2AP ID it shall store it for the duration of the UE-
associated logical X2-connection for this UE. Once known to source eNB this IE is included in all UE associated
X2-AP signalling. The New eNB UE X2AP ID shall be unique within the eNB logical node.
eNB1 Measurement ID:
An eNB1 Measurement ID shall be allocated so as to uniquely identify the measurement configuration over the
X2 interface within the eNB that requests the measurement. The eNB1 Measurement ID shall be unique within
the eNB logical node.
eNB2 Measurement ID:
An eNB2 Measurement ID shall be allocated so as to uniquely identify the measurement configuration over the
X2 interface within the eNB that performs the measurement. The eNB2 Measurement ID shall be unique within
the eNB logical node.
6.2.2 PLMN Identity
A Public Land Mobile Network is uniquely identified by its PLMN Identity.
6.2.3 Globally Unique MME Identifier (GUMMEI)
The Globally Unique MME Identifier consists of a PLMN Identity, a MME Group Identity and a MME Code, as
defined in [11].
An MME logical node may be associated with one or more GUMMEI, but each GUMMEI uniquely identifies an MME
logical node [11].
6.2.4 Global eNB ID
The Global eNB ID, used to globally identify an eNB, is defined in [2].
6.2.5 E-UTRAN Cell Global Identifier (ECGI)
The ECGI, used to globally identify a cell, is defined in [2].
ETSI

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3GPP TS 36.401 version 8.5.0 Release 8 12 ETSI TS 136 401 V8.5.0 (2009-04)
6.2.6 Tracking Area Identity
This is the identity used to identify tracking areas.
6.2.7 E-RAB ID
An E-RAB ID uniquely identifies an E-RAB for one UE accessing via E-UTRAN.
6.2.8 UE Identifiers
6.2.8.1 RNTI
Radio Network Temporary Identifiers (RNTI) are used as UE identifiers within E-UTRAN and in signalling messages
between UE and E-UTRAN. Some types of RNTI exist:
1) C-RNTI
The C-RNTI provides a unique UE identification at the cell level identifying RRC Connection
2) RA-RNTI
The RA-RNTI is used during some transient states, the UE is temporarily identified with a random value for
contention resolution purposes
6.2.8.2 S-Temporary Mobile Subscriber Identity (S-TMSI)
The S-TMSI is a temporary UE identity in order to support the subscriber identity confidentiality. This S-TMSI is
allocated by MME.
6.3 Transport Addresses
The transport layer address parameter is transported in the radio network application signalling procedures that result in
establishment of transport bearer connections.
The transport layer address parameter shall not be interpreted in the radio network application protocols and reveal the
addressing format used in the transport layer.
The formats of the transport layer addresses are further described in [4], [5].
6.4 UE associations in eNB
There are several types of UE associations needed in the eNB: the "eNB UE Context" used to store all information
needed for a UE in active state and the associatio
...