Iuant interface: General aspects and principles

3GPP TS 37.460 V9.1.0 (2019-04)
Technical Specification
3rd Generation Partnership Project;
Technical Specification Group Radio Access Network;
Iuant interface: General aspects and principles
(Release 9)


	
The present document has been developed within the 3rd Generation Partnership Project (3GPP TM) and may be further elaborated for the purposes of 3GPP. 
The present document has not been subject to any approval process by the 3GPP Organizational Partners and shall not be implemented. 
This Specification is provided for future development work within 3GPP only. The Organizational Partners accept no liability for any use of this Specification.
Specifications and reports for implementation of the 3GPP TM system should be obtained via the 3GPP Organizational Partners' Publications Offices.


Keywords
radio, antenna


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Contents
 TOC \o "1-9" Foreword	 PAGEREF _Toc6700347 \h 4
1	Scope	 PAGEREF _Toc6700348 \h 5
2	References	 PAGEREF _Toc6700349 \h 5
3	Abbreviations	 PAGEREF _Toc6700350 \h 5
4	General aspects	 PAGEREF _Toc6700351 \h 6
4.1	Introduction	 PAGEREF _Toc6700352 \h 6
4.2	Iuant interface general principles	 PAGEREF _Toc6700353 \h 6
4.3	Iuant interface specification objectives	 PAGEREF _Toc6700354 \h 6
4.4	Iuant interface characteristics	 PAGEREF _Toc6700355 \h 6
5	Functions of the Iuant interface protocols	 PAGEREF _Toc6700356 \h 7
5.1	Physical layer functions	 PAGEREF _Toc6700357 \h 7
5.2	Data link layer functions	 PAGEREF _Toc6700358 \h 7
5.3	Application layer functions	 PAGEREF _Toc6700359 \h 8
5.3.1	Control of RET antennas	 PAGEREF _Toc6700360 \h 8
5.3.2	Application software and configuration data download	 PAGEREF _Toc6700361 \h 8
5.3.3	Alarm reporting	 PAGEREF _Toc6700362 \h 8
5.3.4	Operator specific data storage	 PAGEREF _Toc6700363 \h 8
5.3.5	Control of Tower Mounted Amplifiers (TMAs)	 PAGEREF _Toc6700364 \h 8
6	Other Iuant interface specifications	 PAGEREF _Toc6700365 \h 9
6.1	Iuant interface: Layer 1 (TS 37.461)	 PAGEREF _Toc6700366 \h 9
6.2	Iuant interface: Signalling Transport (TS 37.462)	 PAGEREF _Toc6700367 \h 9
6.3	Void	 PAGEREF _Toc6700368 \h 9
6.4	Summary of Iuant interface Technical Specifications	 PAGEREF _Toc6700369 \h 9
6.5	Iuant interface: Application part specification (TS 37.466)	 PAGEREF _Toc6700370 \h 9
Annex A (informative):	OSI model overview	 PAGEREF _Toc6700371 \h 10
Annex B (informative):	Change History	 PAGEREF _Toc6700372 \h 11

Foreword
This Technical Specification has been produced by the 3rd 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.
1	Scope
The present document is an introduction to the 3GPP TS 37.46x series of Technical Specifications that define the Iuant Interface for UMTS and E-UTRAN. The logical Iuant interface is a Node B/eNB internal interface between the implementation specific O&M function and the RET antennas and TMAs control unit function of the Node B/ eNB. 
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 TS 25.401: "UTRAN Overall Description".
[2]	3GPP TS 37.461: "Iuant Interface: Layer 1".
[3]	3GPP TS 37.462: "Iuant Interface: Signalling Transport".
[4]	void
[5]	ISO/IEC 13239 (2nd Edition, March 2000): "Information Technology – Telecommunications and information exchange between systems – High-level data link control (HDLC) procedures".
[6]	3GPP TS 25.442: "UTRAN implementation-specific O&M transport".
[7]	3GPP TS 37.466: "Iuant interface: Application Part".
3	Abbreviations
For the purposes of the present document, the following abbreviations apply:
HDLC	High-Level Data Link Control
IP	Internet Protocol
O&M	Operations & Maintenance
OSI	Open Systems Interconnection
RET	Remote Electrical Tilting
RETAP	Remote Electrical Tilting Application Part
TMA	Tower Mounted Amplifier
TMAAP	Tower Mounted Amplifier application part
UMTS	Universal Mobile Telecommunications System
E-UTRAN	Evolved UTRAN
4	General aspects
4.1	Introduction
The Iuant interface for the control of RET antennas or TMAs is a logical part of the Node B/eNB as shown in figure 9 of TS 25.401 [1] for UMTS. Therefore, no new UTRAN/E-UTRAN element for the RET antennas or TMAs and no new UTRAN/E-UTRAN element manager is needed. The existing Implementation Specific O&M transport (see TS 25.442 [6] for UMTS) is used for the connection between the RET antennas or TMAs control unit and the Node B element manager.
The Node B/eNB internal interface Iuant between the Implementation Specific O&M function and the RET antenna control unit function is specified in detail in the specifications for layer 1, signalling transport and RET application part (TS 37.461 [2], TS 37.462 [3], TS 37.466 [7]).
4.2	Iuant interface general principles
For the control of RET antennas a standard data interface between the Node B Implementation Specific O&M function and the Node B/eNB RET antenna control function according to TS 25.401 [1] for UMTS is defined by means of which functional parameters of the device can be remotely controlled. The Iuant interface for the RET antenna control is based on a three-layer protocol model. The three-layer model is a compact form of the OSI seven-layer reference model and includes only layers 1, 2 and 7:
-	The Physical Layer (Layer 1) defines the signalling levels and basic data characteristics including the data rates;
-	The Data Link Layer (Layer 2) for the Signalling Transport uses a specific class of the HDLC standard as defined in ISO/IEC 13239 [5];
-	The Application Layer (Layer 7) defines the data payload format and the required command set. This layer is called the "Iuant: Application Part".
This compact model for the control interface provides an efficient protocol stack suitable for implementation on a single embedded micro-controller.
4.3	Iuant interface specification objectives
The Iuant interface specifications shall facilitate the following:
-	Controlling the tilting of RET antennas remotely from the O&M Network and locally from the Node B;
-	Indicating of TMA alarms and optionally controlling the gain of TMAs remotely from the O&M Network and locally from the Node B;
-	Interfacing a mix of RET antennas, TMAs and Node Bs from different vendors;
-	Providing RET or TMAs functionality in the UTRAN/E-UTRAN accompanied by an appropriate set of signalling commands and control parameters
-	Support of error and alarm handling.
4.4	Iuant interface characteristics
The Iuant interface has a protocol structure as shown below in figure 4.4.1.
EMBED Word.Picture.8
Figure 4.4.1: Protocol structure for Iuant interface
As the Iuant and the Implementation Specific O&M are different interfaces with e.g. different addressing schemes a mediation function is needed. This mediation function uses on one side a protocol that uses the implementation specific O&M bearer (e.g. IP) and on the other side the Iuant protocol.
5	Functions of the Iuant interface protocols
5.1	Physical layer functions
The physical layer provides a multi drop broadcast link between the primary device (Node B/eNB) and all secondary devices (RET antennas or TMAs). Any message transmitted will be received by all other devices. If two devices transmit at the same time, their messages will be garbled.
The connection requires a half duplex communication, which requires an appropriate scheme for the timing and access control of the connection.
5.2	Data link layer functions
The data link layer provides:
-	A data packet communication format;
-	An addressing scheme;
-	A master/slave relationship whereby the primary device controls the half duplex timing;
-	A message checksum scheme to protect from transmission errors;
-	A message sequence numbering scheme which protects layer 7 from:
-	Duplicated messages;
-	Deleted messages;
-	Receiving messages in the wrong order.
-	A flow control mechanism protecting each device from being overrun by messages.
These functions provide layer 7 with a safe full-duplex connection between the primary device and any secondary device. This full duplex connection allows both the primary and secondary device to transmit layer 7 messages to the opposite device of the connection, whenever they need to. Actual delivery time on layer 2 will depend on the layer 2 polling frequency, which is chosen by the primary device.
5.3	Application layer functions
The list of functions on the Iuant interface is the following:
-	Control of RET antennas;
-	Application software and configuration data download;
-	Alarm Reporting;
-	Operator specific data storage;
-	Control of Tower Mounted Amplifiers (TMAs).
5.3.1	Control of RET antennas
A RET device provides means to adjust the electrical tilt of one or multiple antennas. The set of procedures to control RET antennas provides means to control the electrical tilt of one or more RET antennas remotely. The procedures are defined in TS 37.466 [7].
5.3.2	Application software and configuration data download
The interface provides means for downloading new application software and configuration data to a secondary device.
The support of application software download to a secondary device is optional. If a secondary device supports application software download, it shall reset itself and start running the new application software automatically after the completed download. Further details on the software download procedure (e.g. the different states of the secondary device and the supported elementary procedures in these states) are described in subclause 6.1 of TS 37.466 [7].
5.3.3	Alarm reporting
The secondary device reports every change in error status after subscription for alarm reporting by transmitting alarm messages to the primary device. Alarm information can also be interrogated in the application layer.
5.3.4	Operator specific data storage
The secondary device provides means for storage of operator specific data, e.g. inventory information.
5.3.5	Control of Tower Mounted Amplifiers (TMAs)
The TMA device provides means to indicate alarms and optionally to adjust the gain of TMAs. The set of procedures to control TMAs are defined in TS 37.466 [7].
6	Other Iuant interface specifications
6.1	Iuant interface: Layer 1 (TS 37.461)
TS 37.461 [2] specifies the standards allowed for implementation of Layer 1 (physical layer) on the Iuant interface.
6.2	Iuant interface: Signalling Transport (TS 37.462)
TS 37.462 [3] specifies the signalling transport related to RETAP and TMAAP signalling to be used across the Iuant interface.
6.3	Void

6.4	Summary of Iuant interface Technical Specifications
The relationship between the technical specifications that define the Iuant interface is shown in figure 6.4.1.

 EMBED Word.Picture.8  
Figure 6.4.1: Iuant Interface Technical Specifications
6.5	Iuant interface: Application part specification (TS 37.466)
TS 37.466 [7] specifies protocols for application part to be used over the Iuant interface.
Annex A (informative):
OSI model overview

Figure A.1: Relevant OSI model layers
Figure A.1 shows the relevant OSI model layers and the communication paths between the primary and secondary device.
The two important aspects of the OSI model are:
-	It defines a layered structure for the communication software;
-	It provides each layer with an apparent direct link to the same layer at the other device.
However, in real life, the only actual message path between the two devices is through the physical connection between the two layer 1 entities.
The layer 2 entities appear to communicate directly. In actual fact, a message passed from the first device to the second device takes the following path:
-	Layer 2 at the first device passes the message down to Layer 1;
-	Layer 1 transmits the message across the physical connection (for instance a wire) to layer 1 at the second device;
-	Layer 1 at the second device passes the message up to Layer 2 at the second device.
Likewise, layer 7 entities appear to communicate directly. In actual fact, a message passed from the first device to the second device takes the following path:
-	Layer 7 at the first device passes the message down to Layer 2;
-	Layer 2 at the first device passes the message down to Layer 1;
-	Layer 1 transmits the message across the physical connection (for instance a wire) to layer 1 at the second device;
-	Layer 1 at the second device passes the message up to Layer 2 at the second device;
-	Layer 2 at the second device passes the message up to Layer 7 at the second device.
Annex B (informative):
Change History
Change history
DateMeetingTDocCRRevCatSubject/CommentNew version2019-02R3-103R3-190073Text transferred from 25.460 v9.0.1 (changes shown with rev marks)1.9.02019-04RAN#83RP-190576Specification approved by RAN plenary9.1.0








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