Rru redundancy description

RAN

RRU Redundancy Description

Issue 01

Date 2009-03-30

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RANRRU Redundancy Description

About This Document

About This Document

Author

Prepared by Xu Xuhua Date 2009-02-25

Edited by Wang Qian Date 2009-03-12

Reviewed by Xu Xuhua, Liu Bing, and Tang Wenqing Date 2009-03-11

Translated by Liu Yong Date 2009-03-17

Tested by You Yiqing Date 2009-03-18

Approved by Li Qiang Date 2009-03-30

Issue 01 (2009-03-30) Huawei Proprietary and Confidential Copyright © Huawei

Technologies Co., Ltd

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Contents

Contents

1 Change History...........................................................................1-3

2 Introduction...............................................................................2-3

3 Technical Description..................................................................3-33.1 Transmit Diversity + MIMO..........................................................................................................................3-3

3.1.1 Automatic NodeB Operations In the Case of the Faulty TX Channel..................................................3-3

3.1.2 Automatic NodeB Operations After the TX Channel is Restored.........................................................3-3

3.2 No Transmit Diversity....................................................................................................................................3-3

4 Implementation..........................................................................4-34.1 Transmit Diversity + MIMO..........................................................................................................................4-3

4.2 No Transmit Diversity....................................................................................................................................4-3

5 RRU Redundancy Parameters......................................................5-35.1 Description.....................................................................................................................................................5-3

5.2 Values and Ranges..........................................................................................................................................5-3

6 Reference Documents.................................................................6-3



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1 Change History

1 Change History

The change history provides information on the changes in different document versions.

Document and Product Versions

Table 1-1 Document and product versions

Document Version RAN Version

01 (2009-03-30) 11.0

The available time of each feature is subject to the RAN product roadmap.

There are two types of changes, which are defined as follows:

Feature change: refers to the change in the RRU redundancy.

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

01 (2009-03-30)

This is the document for the first commercial release of RAN11.0.



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5 RRU Redundancy Parameters

2 Introduction

Definition

A local cell is configured with two TX channels. If one TX channel is faulty, the system automatically switches it to the other TX channel.

Purposes

In certain remote areas, the RRU maintenance is difficult. In such cases, RRU redundancy plays an important role. RRU redundancy offers a standby TX channel to enhance the reliability and robustness of the RAN network. This feature reduces the period of service disruption caused by the TX channel fault and improves the QoS. Thus, the network coverage of the RRU can be ensured.

Product Versions

Table 2-1 lists the versions of the products that support RRU redundancy.

Table 2-1 Versions of the products supporting RRU redundancy

Product BTS3812E BTS3812A/BTS3812AE

DBS3800 BTS3900/BTS3900A

DBS3900

Version V100R010 or later*

V100R010 or later* V100R010 or later*

V200R010 or later*

V200R010 or later*

NOTE

* The V100R010/V200R010 or a later version supports RRU redundancy in the mode of no TX diversity mode. The V100R011/V200R011 or a later version supports RRU redundancy in TX diversity mode.

Terms

Table 2-1 Terms

Term Definition

Diversity reception Radio reception in which a resultant signal is obtained by



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Term Definition

combining or selecting of signals from two or more independent sources. These sources have been modulated with identical information-bearing signals, but may vary in their fading characteristics at any given instant.

Intended Audience

This document is intended for:

System operators who need a general understanding of RRU redundancy.

Personnel working on Huawei products or systems.

Network Elements Involved

The Network Elements (NEs) involved in RRU redundancy are listed in the following table:

Table 2-1 NEs involved in RRU redundancy

UE NodeB

RNC MSC Server

MGW SGSN GGSN HLR

– √ √ – – – – –

NOTE – = NE not involved √ = NE involved

UE = User Equipment, RNC = Radio Network Controller, MSC Server = Mobile Service Switching Center Server, MGW = Media Gateway, SGSN = Serving GPRS Support Node, GGSN = Gateway GPRS Support Node, HLR = Home Location Register



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3 Technical Description

RRU (Remote Radio Unit) redundancy means that two TX channels are configured for the RRU in a cell. If a TX channel is faulty, the system automatically switches it to the standby TX channel. During the switchover, the ongoing services are disrupted and the logic cell is re-established.

Based on the cell configuration mode, RRU redundancy is classified into the following two modes:

Transmit diversity + MIMO (Multiple Input Multiple Output)

No transmit diversity

3.1 Transmit Diversity + MIMOWhen the transmit diversity + MIMO mode is used in the cell, the system is automatically switched to the no transmit diversity or non-MIMO mode if a TX channel is faulty. When the TX channel is restored, the system is automatically switched back to the transmit diversity + MIMO mode.

3.1.1 Automatic NodeB Operations In the Case of the Faulty TX Channel

When the transmit diversity is used in the cell, the NodeB performs the following operations if a faulty TX channel is detected:

Step 1 The NodeB calculates the maximum available transmit power Ptot for the cells of which the transmit diversity capabilities are changed. The available power of the standby TX channel is the basis for the calculation.

Ptot = Maximum available TX power of the standby TX channel – TX power assigned for the cells of which the transmit diversity capabilities are not changed on the standby TX channel

Step 2 The NodeB determines again the maximum available TX power for each cell of which the transmit diversity capability is changed.

The NodeB configures the TX power Pj for each cell of which the transmit diversity capability is changed on the TX channel (Pj = Original TX power of the cell – 3 dB). If Ptot – ∑Pj > 0, the NodeB assigns the remaining power evenly to the cells of which the transmit



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diversity capabilities are changed. The available power of each cell, however, must not surpass the maximum power originally configured for the cell.

Step 3 The RNC performs the corresponding operations based on the value of Cell Capability Auto Handle Switch.

If Cell Capability Auto Handle Switch is not set to TX_DIVERSITY_ON_TO_OFF, the RNC does not send the related command to the NodeB. You can infer that the procedure is complete.

If Cell Capability Auto Handle Switch is set to TX_DIVERSITY_ON_TO_OFF and the power meets the condition MaxPower(rnc) <= MaxPower(nodeB) + 3 dB, the RNC requests the NodeB to re-establish the cell. The cell re-establishment disrupts the ongoing services and the disruption period is less than 30s.

NOTE

The NodeB does not delete the logical cell before receiving the cell re-establishment command from the RNC.

----End

3.1.2 Automatic NodeB Operations After the TX Channel is Restored

When the NodeB detects that the number of available TX channels of the current cell becomes 2 from 1 and the automatic NodeB operations were triggered in the cell because of switchover from transmit diversity to no transmit diversity, the NodeB performs the following operations:

Step 1 After the transmit diversity configuration specific to the cells is complete, the NodeB updates the available maximum transmit power for each cell of which the transmit diversity capability is changed.

Step 2 The RNC performs the corresponding operations based on the messages reported by the NodeB.

If Cell Capability Auto Handle Switch is not set to TX_DIVERSITY_OFF_TO_ON, you can infer that the procedure is complete.

If Cell Capability Auto Handle Switch is set to TX_DIVERSITY_OFF_TO_ON, the RNC performs Step 3.

Step 3 For each cell of which Tx Diversity Capability is Enable, the RNC checks the diversity mode configured for the cell.

If the diversity mode is activated (TX diversity indication = TRUE) and the power meets the condition MaxPower(rnc) <= MaxPower(nodeB), all the users in the cell are removed and the RNC requests the NodeB to re-establish the cell with transmit diversity. The cell re-establishment disrupts the ongoing services and the disruption period is less than 30s.

If the diversity mode is deactivated (TX diversity indication = FALSE), the cell is not re-established.

----End



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3.2 No Transmit DiversityIn the mode of no transmit diversity, a local cell is configured with two TX channels. Of the two TX channels, one is the active channel and the other is the standby channel. The system triggers the cell re-establishment if the active TX channel is faulty. The resource assignment is performed on the standby TX channel, and then the cell automatically switches the active TX channel to the standby TX channel. The cell re-establishment disrupts the ongoing services and the disruption period is less than 30s.



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4 Implementation

The following describes the RRU redundancy implementation in two modes.

4.1 Transmit Diversity + MIMOStep 1 Activate the transmit diversity capability of the cell.

Before enabling RRU redundancy, you are required to activate the cell transmit diversity at the RNC.

Run the command ADD/MOD CELLSETUP at the RNC to check the value of TX diversity indication, which indicates the status of the transmit diversity mode in the cell. The values and indications are as follows:

TRUE: activated

FALSE: deactivated

Step 2 Set the parameter Cell Capability Auto Handle Switch.

If the RRU is in transmit diversity + MIMO mode, run the command ADD/MOD CELLALGOSWITCH at the RNC to set the parameter Cell Capability Auto Handle Switch. The values and indications are as follows:

TX_DIVERSITY_ON_TO_OFF (transmit diversity becoming not supported)

If the transmit diversity is enabled in the current cell and the parameter Cell Capability Auto Handle Switch is set to TX_DIVERSITY_ON_TO_OFF, the cell re-establishment with no transmit diversity automatically starts.

TX_DIVERSITY_OFF_TO_ON (transmit diversity becoming supported)

If the transmit diversity is disabled (although already configured) in the current cell and the parameter Cell Capability Auto Handle Switch is set to TX_DIVERSITY_OFF_TO_ON, the cell re-establishment with transmit diversity automatically starts.

NOTE

The above options can be selected at the same time. Selecting an option indicates that the corresponding function is enabled.

----End



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4.2 No Transmit DiversityThe two TX channels can be configured on two RRUs (1TX). In this case, the two RRUs (1TX) operate in active/standby mode. The two TX channels can also be configured on one RRU (2TX). In this case, the two TX channels operate in active/standby mode. The data configuration procedure for RRU redundancy is as follows:

Step 1 Configure the sector.

The sector with the RRU redundancy function requires two TX channels. Assume that two RRUs (1TX) are used and subracks 20 and 21 are used.

Two-way demodulation mode

If the site operates in two-way demodulation mode, run the following command to configure the sector:

ADD SEC: STN=0, SECN=0, SECT=REMOTE_SECTOR, ANTM=2, DIVM=NO_TX_DIVERSITY,

ANT1SRN=20, ANT1N=R0A, ANT2SRN=21, ANT2N=R0A;

In this case, the RRUs in subracks 20 and 21 require RF interconnection.

Four-way demodulation mode or four-way economical demodulation mode

If the site operates in four-way demodulation mode or four-way economical demodulation mode, run the following command to configure the sector:

ADD SEC: STN=0, SECN=0, SECT=REMOTE_SECTOR, ANTM=4, DIVM=NO_TX_DIVERSITY,

ANT1SRN=20, ANT1N=R0A, ANT2SRN=20, ANT2N=R0B, ANT3SRN=21, ANT3N=R0A,

ANT4SRN=21, ANT4N=R0B;

In this case, the RRUs in subracks 20 and 21 do not require RF interconnection.

Step 2 Configure the local cell.

If the local cell requires the RRU redundancy function, run the following command to configure the local cell:

ADD LOCELL: LOCELL=0, STN=0, SECN=0, SECT=REMOTE_SECTOR, CN1=MASTER, SRN1=20,

SN1=0, CN2=MASTER, SRN2=21, SN2=0, ULFREQ=9610, DLFREQ=10560, MXPWR=430,

HISPM=FALSE;

NOTE

When you configure RRU redundancy for the local cell, set the cabinet number (CN), subrack number (SRN), and slot number (SN) for two power amplifiers. If RRU redundancy is not configured for the local cell, set the cabinet number (CN), subrack number (SRN), and slot number (SN) for one power amplifier in the case of the mode of no TX diversity.

----End



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5.1 Description

Table 5-1 RRU redundancy parameter description

Parameter ID Description

ANT1N

It is the No. of the first antenna connector; There are one or more antenna channels in one sector. The number of the channels equals antenna magnitude. The antenna channels are identified by antenna connectors at the cabinet top, hereinafter referred to as "antenna connector".

ANT1SRN

Subrack No. of Antenna Channel1: There are one or more antenna channels in one sector. The number of the channels equals antenna magnitude. The antenna channels are identified by antenna connectors at the cabinet top, hereinafter referred to as "antenna connector".

ANT2N

It is the No. of the second antenna connector; There are one or more antenna channels in one sector. The number of the channels equals antenna magnitude. The antenna channels are identified by antenna connectors at the cabinet top, hereinafter referred to as "antenna connector".

ANT2SRN


ANT3N

It is the No. of the third antenna connector; There are one or more antenna channels in one sector. The number of the channels equals antenna magnitude. The antenna channels are identified by antenna connectors at the cabinet top, hereinafter referred to as "antenna connector".

ANT3SRN


ANT4N

It is the No. of the fourth antenna connector; There are one or more antenna channels in one sector. The number of the channels equals antenna magnitude. The antenna channels are identified by antenna connectors at the cabinet top, hereinafter referred to as "antenna connector".



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ANT4SRN


ANTMIt refers to the magnitude of antennas in the sector. Do not use it when Sector Type is Distributed Sector.

CellCapacityAutoHandleSwitch

The algorithms with the above values represent are as follow:

TX_DIVERSITY_ON_TO_OFF: When TX Diversity is on to off, the algorithms of cell capacity auto handle is open.

TX_DIVERSITY_OFF_TO_ON: When TX Diversity is off to on, the algorithms of cell capacity auto handle is open.

CN1Cabinet No. of Power Amplifier1: Power Amplifier refers to the power amplify unit in RRU.

CN2Cabinet No. of Power Amplifier2: Power Amplifier refers to the power amplify unit in RRU.

DIVM TX Diversity Mode of Sector

DLFREQ DL Frequency Channel Number

HISPM High Speed Movement Mode of the Local Cell

LOCELL Local Cell ID

MXPWR

The maximum transmit power of the local cell is the maximum output power at the antenna connector on the cabinet top. The value must stay within the value range supported by the power amplifier; otherwise, the local cell is unavailable.

SECNIt is sequentially numbered in the site. Up to six sectors can be configured to one site.

SECT It indicates type of the sector.

SN1Slot No. of Power Amplifier1:Power Amplifier refers to the power amplify unit in RRU.

SN2Slot No. of Power Amplifier2:Power Amplifier refers to the power amplify unit in RRU.

SRN1Subrack No. of Power Amplifier1: Power Amplifier refers to the power amplify unit in RRU.

SRN2Subrack No. of Power Amplifier2: Power Amplifier refers to the power amplify unit in RRU.

STN It is the number of the site.

TxDiversityIndThis parameter indicates whether transmission diversity configuration of the cell is activated.

ULFREQ UL Frequency Channel Number



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ANT1N

It is the No. of the first antenna connector; There are one or more antenna channels in one sector. The number of the channels equals antenna magnitude. The antenna channels are identified by antenna connectors at the cabinet top, hereinafter referred to as "antenna connector".

5.2 Values and Ranges

Table 5-1 RRU redundancy parameter values and parameter ranges

Parameter ID

Default Value

GUI Value Range Actual Value Range

Unit MML Command

NE

ANT1N -R0A(Cabinet No.0A Ant), R0B(Cabinet No.0B Ant)

R0A, R0B NoneADD SEC(Mandatory)

NodeB

ANT1SRN - 20~254 20~254 NoneADD SEC(Mandatory)

NodeB



NodeB


NodeB



NodeB


NodeB



NodeB


NodeB

ANTM -1(single antenna), 2(two antennas), 4(four antennas)

1, 2, 4 NoneADD SEC(Mandatory)

NodeB

CellCapacityAutoHand

- TX_DIVERSITY_ON_

TX_DIVERSITY_ON

None ADD CELLALGO

RNC



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Parameter ID

Default Value


Unit MML Command

NE

leSwitchTO_OFF, TX_DIVERSITY_OFF_TO_ON

_TO_OFF,TX_DIVERSITY_OFF_TO_ON

SWITCH(Optional)

CN1MASTER

MASTER(Master cabinet)

MASTER NoneADD LOCELL(Optional)

NodeB

CN2MASTER

MASTER(Master cabinet)

MASTER NoneADD LOCELL(Optional)

NodeB

DIVMCOMMON_MODE

COMMON_MODE(Common Mode), HALFFREQ(0.5/0.5 Mode)

COMMON_MODE,HALFFREQ

NoneADD SEC(Optional)

NodeB

DLFREQ - 0~65535 0~65535 NoneADD LOCELL(Mandatory)

NodeB

HISPM

FALSE(ADD LOCELL)

FALSE (Not Support), TRUE (Support)

FALSE, TRUE NoneADD LOCELL(Optional)

NodeB

LOCELL - 0~268435455 0~268435455 NoneADD LOCELL(Mandatory)

NodeB

MXPWR - 0~500 0~50, step: 0.1 dB dBADD LOCELL(Mandatory)

NodeB

SECN - 0~5 0~5 NoneADD SEC(Mandatory)

NodeB

SECT

REMOTE_SECTOR(ADD SEC)-(ADD LOCELL)

REMOTE_SECTOR (Remote Sector), DIST_SECTOR (Distributed Sector)

REMOTE_SECTOR, DIST_SECTOR

NoneADD SEC(Optional)

NodeB

SN1 - 0 0 NoneADD LOCELL(Optional)

NodeB

SN2 - 0 0 NoneADD LOCELL(Optional)

NodeB



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Parameter ID

Default Value


Unit MML Command

NE

SRN1 - 20~254 20~254 NoneADD LOCELL(Mandatory)

NodeB

SRN2 - 20~254 20~254 NoneADD LOCELL(Optional)

NodeB

STN - 0~4294967295 0~4294967295 NoneADD SEC(Mandatory)

NodeB

TxDiversityInd

- TRUE, FALSE TRUE, FALSE NoneADD CELLSETUP(Mandatory)

RNC

ULFREQ - 0~65535 0~65535 NoneADD LOCELL(Mandatory)

NodeB



NodeB

The Default Value column is valid for only the optional parameters.

The "-" symbol indicates no default value.



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6 Reference Documents

The following lists the reference documents related to the feature:

1. Basic Feature Description of Huawei UMTS RAN11.0 V1.5

2. Optional Feature Description of Huawei UMTS RAN11.0 V1.5



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