Multiple RRUs in One Cell

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Multiple RRUs in One CellRAN12.0

Feature Parameter Description

Issue 03

Date 2010-12-20

HUAWEI TECHNOLOGIES CO., LTD.


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Copyright Huawei Technologies Co., Ltd. 2011. All rights reserved.

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All other trademarks and trade names mentioned in this document are the property of their respectiveholders.

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The purchased products, services and features are stipulated by the contract made between Huawei andthe customer. All or part of the products, services and features described in this document may not bewithin the purchase scope or the usage scope. Unless otherwise specified in the contract, all statements,

information, and recommendations in this document are provided "AS IS" without warranties, guarantees orrepresentations of any kind, either express or implied.

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

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WCDMA RANMultiple RRUs in One Cell Contents

Issue 03 (2010-12-20) Huawei Proprietary and ConfidentialCopyright Huawei Technologies Co., Ltd

ii

Contents

1 Introduction ................................................................................................................................1-11.1 Scope ............................................................................................................................................ 1-11.2 Intended Audience ........................................................................................................................ 1-11.3 Change History .............................................................................................................................. 1-1

2 Technical Description ..............................................................................................................2-12.1 Overview of Multiple RRUs in One Cell ........................................................................................ 2-12.2 Distributed Sector Configuration ................................................................................................... 2-12.3 0.5/0.5 Configuration ..................................................................................................................... 2-2

3 Engineering Guidelines...........................................................................................................3-13.1 Distributed Sector Configuration ................................................................................................... 3-13.2 0.5/0.5 Configuration ..................................................................................................................... 3-1

4 Parameters .................................................................................................................................4-15 Counters......................................................................................................................................5-16 Glossary ......................................................................................................................................6-17 Reference Documents .............................................................................................................7-1


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WCDMA RANMultiple RRUs in One Cell 1 Introduction

03 (2010-12-20) Huawei Proprietary and ConfidentialCopyright Huawei Technologies Co., Ltd

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1 Introduction

1.1 Scope

This document describes the Multiple RRUs in One Cell feature. It also describes the engineeringguidelines of this feature.

1.2 Intended Audience

This document is intended for:

Personnel who are familiar with WCDMA basics

Personnel who need to understand Multiple RRUs in One Cell

Personnel who work with Huawei products

1.3 Change History

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 Multiple RRUs in One Cell feature.

Editorial change: refers to the change in wording or the addition of the information that was notdescribed in the earlier version.

Document Issues

The document issues are as follows:

03 (2010-12-20)

02 (2010-06-20)

01 (2010-03-30)

Draft (2009-12-05)

03 (2010-12-20)

This is the document for the third commercial release of RAN12.0.

Compared with issue 02 (2010-06-20) of RAN12.0, this issue optimizes the description and thedocument is renamed from Cell Digital Combination and Splitto Multiple RRUs in One Cell.

02 (2010-06-20)

This is the document for the second commercial release of RAN12.0.

Compared with issue 01 (2010-03-30) of RAN12.0, this issue adds the information about RRUdouble-antenna receive mode in distributed sector configuration mode.

01 (2010-03-30)

This is the document for the first commercial release of RAN12.0.

Compared with issue Draft (2009-12-05) of RAN12.0, this issue optimizes the description.

Draft (2009-12-05)

This is the draft of the document for RAN12.0.


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WCDMA RANMultiple RRUs in One Cell 1 Introduction


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This is a new document.


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WCDMA RANMultiple RRUs in One Cell 2 Technical Description


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2 Technical Description

2.1 Overview of Multiple RRUs in One Cell

With the multiple RRUs in one cell feature, multiple RRUs can be used to cover different areas in onecell. In this case, the areas covered by one cell will be more flexible.

The Multiple RRUs in One Cell feature is adopted by distributed base stations. It is mainly applicable tocoverage scenarios such as indoor space, high-speed railways, and expressways.

The multiple RRUs in one cell feature is implemented by the following two modes.

Distributed sector configuration mode (WRFD-010205 Cell Digital Combination and Split): It is mainlyapplicable to coverage scenarios such as indoor spots. In this mode, a maximum of 16 RRUs cancoexist in one cell to cover different areas.

0.5/0.5 configuration mode: It is mainly applicable to coverage scenarios such as high-speed railwaysand expressways. In this mode, a maximum of two RRUs can coexist in one cell to cover different

areas.

The following sections will describe the detailed information about the two configuration modes.

2.2 Distributed Sector Configuration

This section describes the feature WRFD-010205 Cell Digital Combination and Split.

The distributed sector configuration mode is mainly applicable to coverage scenarios such as indoorspots. In this configuration mode, a maximum of 16 RRUs can coexist in one cell.

The distributed sector configuration mode adopts digital combination and split to process the uplink anddownlink signals.Figure 2-1shows the process of the uplink digital combination and downlink digital split.

In uplink digital combination, the uplink signal from the transport channel of the current RRU and theuplink signal from the lower-level RRU are combined for transmission to the upper-level RRU or BBU. Indownlink digital split, the downlink signals from the upper-level RRU or BBU are sent to the transportchannel of the current RRU and the lower-level RRU simultaneously.

Figure 2-1 The process of the uplink digital combination and downlink digital split


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In distributed sector configuration mode, each RRU can be configured in single-antenna ordouble-antenna receive mode. Note that in the same sector, the antenna magnitude of all the RRU mustbe the same.

In distributed sector configuration mode, the digital combination of uplink signals increases the

background noises. If n RRUs coexist in one cell, then the increase of background noises equals 10 xlg(n). In an indoor environment, the health standards for electromagnetic radiation should be taken intoconsideration. Generally, the transmit power of an antenna is below 15 dBm, and the maximum transienttransmit power of a UE is above 21 dBm. Indoor coverage mainly focuses on capacity. It takes intoconsideration limited downlink power rather than limited uplink coverage. In addition, it does not havehigh requirements for uplink sensitivity. Therefore, the increase of background noises caused by digitalcombination does not affect system performance.

2.3 0.5/0.5 Configuration

The 0.5/0.5 configuration mode is mainly applicable to coverage scenarios such as high-speed railwaysand expressways. In this configuration mode, a maximum of two RRUs can coexist in one cell.

In the downlink, two RRUs transmit the same data; in the uplink, signals from two RRUs are consideredas signals from multiple antennas in one cell during demodulation, and therefore noise superimpose isnot caused.

Figure 2-2shows the 0.5/0.5 configuration.

Figure 2-2 The 0.5/0.5 configuration

In 0.5/0.5 configuration mode, a maximum of two RRUs can coexist in one cell and each RRU can be

configured in single-antenna or double-antenna receive mode. If the RRU receives signals insingle-antenna mode, the two-channel demodulation is applied to the cell. If the RRU receives signals indouble-antenna mode, the four-channel demodulation is applied to the cell. Compared with two-channeldemodulation, four-channel demodulation consumes twice the amount of baseband resources.

The 0.5/0.5 configuration mode solves the problem that the handover between two cells in one NodeBfails because the handover area is excessively small. In addition, this mode meets the requirements ofhigh-speed handover in the coverage scenarios such as high-speed railways and expressways. In thecase of traditional configuration, the handover between two cells in one NodeB for the UE in high-speedmotion fails easily because of fast signal attenuation and small handover area. In the case of 0.5/0.5configuration, two RRUs are located in the same cell but cover different areas. In this case, there is nohandover process for the UE in high-speed motion.Figure 2-3shows the comparison betweentraditional configuration and 0.5/0.5 configuration.


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Figure 2-3 Comparison between traditional configuration and 0.5/0.5 configuration


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WCDMA RANMultiple RRUs in One Cell 3 Engineering Guidelines


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3 Engineering Guidelines

3.1 Distributed Sector Configuration

This section describes the engineering guideline about the feature WRFD-010205 Cell DigitalCombination and Split.

In distributed sector configuration mode, one CPRI port supports a maximum of eight cascaded RRUs. Amaximum of eight RRUs coexist in one cell and a maximum of three distributed cells are supported.

The BBU enables digital combination of uplink signals from a maximum of two CPRI ports. A maximumof 16 RRUs can coexist in one cell.

Due to the delay, the length of the interconnection optical cables between the RRUs that are located inthe same cell and have neighboring coverage areas should be less than four kilometers.

In the case of the DBS3900 and iDBS3900, when the WBBPa board is configured, each RRU supportsonly the one-antenna receive mode; when other baseband boards are configured, each RRU cansupport the one-antenna or two-antenna receive mode.

In distributed sector configuration mode, the digital combination of uplink signals increases thebackground noises. When configuring the background noise of the cell, the increase of backgroundnoise caused by digital combination needs to be taken into consideration. The background noise of thecell is configured by the BackgroundNoise parameter.

For details on how to configure and activate the feature, see the RAN Reconfiguration Guide.

3.2 0.5/0.5 Configuration

In 0.5/0.5 configuration mode, one CPRI port supports a maximum of four RRUs, with two RRUscoexisting in one cell. Thus, a maximum of two cells are supported. The two RRUs that are connected to

different CPRI ports cannot be configured in one cell.

One BBU supports a maximum of six CPRI ports and a maximum of 24 RRUs, with two RRUs coexistingin one cell. Thus, a maximum of 12 cells are supported.

In four-channels demodulation mode, the number of cells supported by the WBBPb3 and WBBPb4boards in the DBS3900 or iDBS3900 decreases from 6 to 3. One WBBPb board (WBBPb1, WBBPb2,WBBPb3, or WBBPb4) supports three CPRI ports and three cells, with two RRUs coexisting in one cell.Thus, a maximum of six RRUs are supported.

A hybrid configuration of a cell in 0.5/0.5 configuration mode and an ordinary cell is not recommended.

Due to the delay, the length of the interconnection optical cables between the RRUs in the same cell

must be less than four kilometers.To activate the 0.5/0.5 configuration mode, configure the parameters as follows:

Run the MML command ADD SEC,

Configure the sector type SECT to REMOTE_SECTOR, and then configure the diversity mode DIVMto HALFFREQ(0.5/0.5 Mode).

Configure the cover type COVERTYPE.

If the COVERTYPE parameter is set to SAMEZONE (Same Cover Type), two RRUs cover the samearea and the total output power of the RRUs equals the output power of the cell.

If the COVERTYPE parameter is set to DIFFZONE (Different Cover Type), two RRUs coverdifferent areas and the output power of each RRU equals the output power of the cell.
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WCDMA RANMultiple RRUs in One Cell 3 Engineering Guidelines


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Configure the antenna magnitude ANTM through the MML command ADD SEC and the demodulationwork mode DEMMODE through the MML command ADD ULGROUP.

If the RRU uses the single-antenna receive mode, set the ANTM parameter to 2(two antennas), andset the DEMMODE to DEM_2_CHAN (2-Channels Demodulation Mode).

If the RRU uses the double-antenna receive mode, set the ANTM parameter to 4(four antennas),and set the DEMMODE to DEM_4_CHAN (4-Channels Demodulation Mode).

Run the MML command ADD LOCELL,

Configure the sector type SECT to REMOTE_SECTOR,

Configure the two TX way TTW to False. The cells in 0.5/0.5 configuration mode cannot use the twoTX way.

The cells in 0.5/0.5 configuration mode support the high speed access feature. To enable high speedaccess, set the high speed movement mode HISPM to TRUE. Then, you can specify the speed rate(SPR) for high speed access. For details, see theHigh Speed Access Feature Parameter Description.
http://high%20speed%20access.htm/http://high%20speed%20access.htm/http://high%20speed%20access.htm/http://high%20speed%20access.htm/


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WCDMA RANMultiple RRUs in One Cell 4 Parameters


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4 ParametersTable 4-1 Parameter description

ParameterID NE MML Command Meaning

BackgroundNoise

BSC6900

ADDUCELLCAC(Optional)MODUCELLCAC(Optional)

Meaning: If [Auto-Adaptive Background Noise UpdateSwitch] is set to OFF, it is used to set background noise ofthe cell. If [Auto-Adaptive Background Noise Update Switch]is set to ON, new background noise is restricted by thisparameter and BgnAbnormalThd. For detailed informationof this parameter, refer to the 3GPP TS 25.133.

GUI Value Range: 0~621Actual Value Range: -112~-50, step:0.1Unit: dBm

Default Value: 61

SECT NodeB MODLOCELL(Mandatory)ADDLOCELL(Mandatory)

Meaning: sector type

GUI Value Range: LOCAL_SECTOR(Local Sector),REMOTE_SECTOR(Remote Sector),DIST_SECTOR(Distribute Sector)Actual Value Range: LOCAL_SECTOR,REMOTE_SECTOR, DIST_SECTORUnit: NoneDefault Value: -

SECT NodeB MOD

SEC(Optional)ADD SEC(Optional)

Meaning: Sector type

GUI Value Range: LOCAL_SECTOR(Local Sector),REMOTE_SECTOR(Remote Sector),DIST_SECTOR(Distribute Sector)Actual Value Range: LOCAL_SECTOR,REMOTE_SECTOR, DIST_SECTORUnit: NoneDefault Value: LOCAL_SECTOR

DIVM NodeB ADD SEC(Optional) Meaning: Diversity mode of the sector

GUI Value Range: COMMON_MODE(Common Mode),

HALFFREQ(Half Frequency)Actual Value Range: COMMON_MODE, HALFFREQUnit: NoneDefault Value: COMMON_MODE

COVERTYPE

NodeB ADD SEC(Optional) Meaning: Cover type of the sector

GUI Value Range: SAMEZONE(Same Zone),DIFFZONE(Different Zone)Actual Value Range: SAMEZONE, DIFFZONEUnit: NoneDefault Value: -


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WCDMA RANMultiple RRUs in One Cell 4 Parameters


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ParameterID

NE MML Command Meaning

ANTM NodeB ADD SEC(Optional) Meaning: Magnitude of antennas in the sector

GUI Value Range: 1, 2, 4Actual Value Range: 1, 2, 4Unit: NoneDefault Value: -

DEMMODE NodeB ADDULGROUP(Mandatory)

Meaning: It is the Demodulation Work Mode of the uplinkresource group.

GUI Value Range: DEM_2_CHAN(2-ChannelsDemodulation Mode), DEM_4_CHAN(4-ChannelsDemodulation Mode), DEM_ECON_4_CHAN(Economical4-Channels Demodulation Mode)

Actual Value Range: DEM_2_CHAN, DEM_4_CHAN,DEM_ECON_4_CHANUnit: NoneDefault Value: -

TTW NodeB MODLOCELL(Optional)ADDLOCELL(Optional)

Meaning: Two Tx way of the local cell

GUI Value Range: FALSE(False), TRUE(True)Actual Value Range: FALSE, TRUEUnit: NoneDefault Value: False

HISPM NodeB MOD

LOCELL(Optional)ADDLOCELL(Optional)

Meaning: High speed movement mode

GUI Value Range: FALSE(False), TRUE(True)Actual Value Range: FALSE, TRUEUnit: NoneDefault Value: False

SPR NodeB MODLOCELL(Optional)ADDLOCELL(Optional)

Meaning: Speed rate

GUI Value Range: 250, 400, 500Actual Value Range: 250, 400, 500Unit: km/hDefault Value: -


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WCDMA RANMultiple RRUs in One Cell 5 Counters


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5 CountersThere are no specific counters associated with this feature.


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WCDMA RANMultiple RRUs in One Cell 6 Glossary


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6 GlossaryFor the acronyms, abbreviations, terms, and definitions, see theGlossary.
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WCDMA RANMultiple RRUs in One Cell 7 Reference Documents


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7 Reference DocumentsNone.