4 General aspects

37.4603GPPIuant interface: General aspects and principlesRelease 17TS

4.1 Introduction

The Iuant interface for the control of RET antennas or TMAs is a logical part of the RAN Node as shown for a Node B in figure 9 of TS 25.401 [1] for UTRAN. Therefore, no new RAN element for the RET antennas or TMAs and no new RAN 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 Iuant interface 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

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 RAN Node from different vendors;

– Providing RET or TMAs functionality 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.

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.