Remote Electrical Tilt

Remot emote e Elect Electri rical cal Til iltt Featu ture re Paramete Parameterr Description Copyrigh t © Huawei Technolog Technolog ies Co., Ltd. 2010. 2010. All righ ts reserved. No part of this document may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Technologies Co., Ltd.

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Notice The information in this document is subject to change without notice. Every effort has been made in the preparation of this document to ensure accuracy of the contents, but all statements, information, and recommendations in this document do not constitute the warranty of any kind, express or implied.

Huawei Proprietary and Confidential Copyright © Huawei Technologies Co., Ltd

Remote Electrical Tilt

Contents

Contents Document Author ing Information .............................................Error! Bookmark not defined. 1 Introduc tion ................................................................................................................................1-1 1.1 Scope ............................................................................................................................................ 1-1 1.2 Intended Audience ........................................................................................................................ 1-1 1.3 Change History.............................................................................................................................. 1-1

2 Technical Descrip tio n ..............................................................................................................2-1 2.1 Operating Principles of RET.......................................................................................................... 2-1 2.2 Operating Principles of Huawei RET............................................................................................. 2-2

3 Parameters

.................................................................................................................................3-1

4 Counters ......................................................................................................................................4-1 5 Gloss ary ......................................................................................................................................5-1 6 Reference Documents .............................................................................................................6-1

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1

Introduction

1 Introduction 1.1 Scop e The remote electrical tilt (RET, corresponding to MRFD-210602 Remote Electrical Tilt) refers to an antenna system whose tilt is controlled electrically. This document describes a solution for remote adjustment of the antenna tilt.

1.2 Intend ed Aud ience This document is intended for: 

Personnel who need to understand RET



Personnel who work with Huawei products

1.3 Change Hist ory This section provides information on the changes in different document versions. There are two types of changes, which are defined as follows: 

Feature change: refers to the change in the RET feature of a specific product version.



Editorial change: refers to the change in wording or the addition of the information that was not described in the earlier version.

Document Issues The document issues are as follows: 

Draft (2010-01-20)

Draft (2010-01-20) This is the draft of the document.

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2

Technical Description

2 Technical Description After an antenna is installed, the tilt of the antenna needs to be ad justed for the purpose of network optimization. With the RET feature, the phases of signals that reach the elements of the array antenna can be adjusted through electrical control, so as to change the vertical pattern of the antenna. The tilt of the RET antenna can be adjusted after the system is powered on and be monitored in real time. In this way, precise adjustment of the antenna tilt can be achieved. The RET feature provides the following benefits: 

The RET antennas at more than one site can be remotely adjusted at the same time. Therefore, the efficiency of adjusting the antenna tilt is improved and the cost of network optimization is reduced.



The adjustment of RET antennas can be performed irrespective of weather conditions.



It is easy to adjust the RET antennas at the sites that are difficult to reach.

The operating principles of RET are described in this chapter.

2.1 Operatin g Prin cip les of RET The tilt of the RET antenna can be adjusted remotely. The phase shifter of the antenna can be controlled by the stepper motor outside or inside the antenna. You can adjust the antenna tilt after the system is powered on and monitor the tilt in real time. Therefore, the precise remote adjustment of the antenna tilt can be achieved. Figure 2-1 shows the operating principles of the RET antenna. Figure 2-1 Operating principles of the RET antenna Radome

Phase shifter

Pulling bar

RCU Control cable (DC+ control signals)

The Remote Control Unit (RCU) is the driving motor of the phase shifter of the RET antenna. The RCU receives and executes the control commands from the MBTS to drive the stepper motor. A pulling bar connects the stepper motor and the phase shifter. When the stepper motor is triggered, the pulling bar moves and then the phase of the phase shifter changes through the gears. In this situation, the phase of

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each element of the array antenna changes regularly. Then, the direction of the main beam of the antenna changes accordingly. Thus, the antenna tilt is adjusted.

2.2 Operatin g Prin cip les of Huawei RET Huawei MBTS supports the following types of RET antenna connection: 

Directly connect the RET through multicore cables: It is applicable when the distance between the RRU and the RCU is shorter than 20 meters.

Figure 2-2 DBS Station connect the RET Antenna directly



Connect the RET via SBT: It is applicable when the distance between the RRU and the RCU is longer than 20 meters and the TMA is not used in the system.

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Figure 2-3 DBS Station connect the RET Antenna via SBT

Figure 2-4 BTS Station connect the RET Antenna via SBT

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



Connect the RET together with the STMA: It is applicable when th e distance between the RRU and the RCU is longer than 20 meters and the TMA is required by the system.

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Figure 2-5 DBS Station connect the RET Antenna together with STMA

Figure 2-6 BTS Station connect the RET Antenna together with STMA

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The MBTS supplies the DC power to the stepper motor and communicates with it through the AISG interface on the motor. In the Huawei RET solution, the RET antenna can be controlled remotely or locally through a command sent from the M2000 or LMT respectively. 



When directly connect the RET through multicore cables, the process of RET antenna control is as follows: 1.

The M2000 or LMT issues the control command to the BBU, and then the BBU sends the command to the RRU.

2.

The RRU modulates the control command into RS485 signals and then transmits the signals from the RS485 port to the RCU through the control cable.

When connect the RET via the SBT, the process of RET antenna control is as follows:

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1.


2.

The RRU modulates the control command into On-Off-Keying (OOK) signals and then transmits the signals and the DC power from the RF port to the SBT.

3.

The SBT demodulates the OOK signals into RS485 signals and then transmits the signals and part of the DC power to the RCU.


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Remote Electrical Tilt 

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When conect the RET together with STMA, the process of RET antenna control is as follows: 1.


2.

The RRU modulates the control command into OOK signals and then transmits the signals and the DC power from the RF port to the STMA.

3.

The STMA demodulates the OOK signals into RS485 signals and then transmits the signals and part of the DC power to the RCU.

The Huawei RET solution supports the RET cascading control. Several cascaded RET antennas can be controlled by the signals coming from the same control cable. The cascading solution helps save the cost of the SBTs.

Sector

1

Antenna

Sector

2

Antenna

RCU

RCU

Sector

3

Antenna

RCU

SBT

MBTS

The Huawei RET solution also supports the 2G/3G RET cascading control. 3G RET antennas can be cascaded with 2G RET antennas. When they are cascaded, the tilts of the 2G RET antennas can be controlled on the OMC for 3G, and the tilts of the 3G RET antennas can also be controlled on the OMC for 2G. The cascading helps save the cost of SBTs and STMAs when the 2G and 3G RET antennas are installed at the same place.

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Dual-band Antenna

3G

R C U

R C U

SBT

3G/2G NodeB

2-8

2G/3G BTS


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Parameters

3 Parameters The following describes the parameters related to Remote Electrical Tilt feature. Table 3-1 Parameter description Parameter ID

NE

MML

Descrip tio n

TILT

NodeB

SET ANTTILT

Meaning: RET antenna tilt (0.1 degree) GUI Value Range: -100~300 Actual Value Range: -10~30; step: 0.1 Unit: degree Default Value: -

AER

NodeB

SET TILTAER

Meaning: Tilt error threshold for alarms (0.1 degree). An RET data abnormal alarm is reported when the difference between the tilt of an RET antenna and the preset tilt exceeds the threshold. GUI Value Range: 0~10 Actual Value Range: 0.0~1.0; step: 0.1 Unit: degree Default Value: 5

The Ac tu al Valu e Rang e of the parameter TILT, described by the table above, means the data that the user can send out from the BTS to the RET. Whether the RET can be actually adjusted to this tilt also rests with the tilt range supported by the RET antenna, which is varies with models and vendors.

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Counters

4 Counters There are no specific counters associated with this feature.

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Glossary

5 Glossary For the acronyms, abbreviations, terms, and definitions, see the Glossary.

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Reference Documents

6 Reference Documents There are no specific reference documents associated with this feature.

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Remote Electrical Tilt

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