ENodeB Technical Description(V100R003C00_14)(PDF)-En

8/11/2019 ENodeB Technical Description(V100R003C00_14)(PDF)-En

1/133

eNodeB

V100R003C00

Technical Description

Issue 14

Date 2013-11-30

HUAWEI TECHNOLOGIES CO., LTD.


2/133

Copyright Huawei Technologies Co., Ltd. 2013. All rights reserved.

No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent of Huawei Technologies Co., Ltd. Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd. All other trademarks and trade names mentioned in this document are the property of their respective holders. Notice

The purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase 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 or representationsof 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 a warranty of any kind, express or implied.

Huawei Technologies Co., Ltd. Address: Huawei Industrial Base

Bantian, LonggangShenzhen 518129People's Republic of China

Website: http://www.huawei.com

Email: [email protected]

Issue 14 (2013-11-30) Huawei Proprietary and ConfidentialCopyright Huawei Technologies Co., Ltd.

i
http://www.huawei.com/


3/133

About This Document

PurposeThis document provides the LTE-SAE system architecture and the following information aboutthe eNodeB: basic functions, structures, environment monitoring principles, clock synchronization modes, operation and maintenance, reliability, topologies, typical hardwareconfigurations, and technical specifications.

Product VersionsThe following table lists the product versions related to this document.

Product Name Version

BTS3900 LTE V100R003C00

BTS3900A LTE V100R003C00

BTS3900L LTE V100R003C00

DBS3900 LTE V100R003C00

Intended AudienceThe intended audiences of this document are:

l Network planning engineersl Field engineersl System engineers

Organization1 Changes in the eNodeB Technical Description

eNodeBTechnical Description About This Document


ii


4/133

This chapter describes the changes in the eNodeB Technical Description .

2 LTE-SAE System Architecture

This chapter describes Long Term Evolution-System Architecture Evolution (LTE-SAE) system

architecture, including the position of eNodeBs in the system and the functions of the Network Elements (NEs) in the network.

3 eNodeB Functions

This chapter describes the functions of eNodeBs. As the radio access equipment in the LTE-SAE system, eNodeBs perform radio resource management, packet c ompression and ciphering,user plane packet routing, MME selection, and message scheduling and transmission.

4 eNodeB Structure

This chapter describes the structure of an eNodeB. eNodeBs are designed based on a distributedarchitecture. Each eNodeB consists of two basic types of component: baseband unit BBU3900

and Radio Frequency (RF) unit RRU or RFU.5 Environment Monitoring Principles

This chapter describes environment monitoring principles for eNodeBs. Environmentmonitoring detects the following environmental conditions of an eNodeB: temperature,humidity, water damage, smoke, unauthorized access, and power distribution faults. Toimplement environment monitoring, the eNodeB is equipped with environment monitoringdevices and configured with external environment alarms, including Boolean alarms and anEMUA alarm .

6 eNodeB Synchronization Modes

This chapter describes the clock synchronization modes of eNodeBs. eNodeBs supportsynchronization with the following clocks: GPS/RGPS clock, GLONASS clock, IEEE1588 V2clock, Clock over IP, synchronous Ethernet, 1 PPS+TOD clock, BITS clock, and E1/T1 lineclock. If an eNodeB fails to obtain clock signals, it works in free-run mode for a certain periodof time.

7 Operation and Maintenance of eNodeBs

This chapter describes operation and maintenance of eNodeBs. The operation and maintenance(OM) system of eNodeBs manages, monitors, and maintains the software, hardware, andconfiguration data of the eNodeBs. In addition, the OM system provides various OM modes tomeet requirements.

8 eNodeB Reliability

This chapter describes eNodeB reliability, which includes system reliability, hardwarereliability, and software reliability.

9 eNodeB Topologies

This chapter d escribes the topologi es on the S1 interface, topologies on the common public radiointerface (CPRI), and CPRI port specifications.

10 Typical Hardware Configurations of an eNodeB

This chapter describes the hardware configurations of an eNodeB.

11 Product Specifications



iii


5/133

Product specifications of the eNodeB include technical specifications of the BBU3900, radiofrequency unit (RFU), and remote radio unit (RRU) and engineering specifications of each typeof cabinet.

ConventionsSymbol Conventions

The symbols that may be found in this document are defined as follows.

Symbol Description

Indicates an imminently hazardous situation which, if notavoided, will result in death or serious injury.

Indicates a potentially hazardous situation which, if notavoided, could result in death or serious injury.

Indicates a potentially hazardous situation which, if notavoided, may result in minor or moderate injury.

Indicates a potentially hazardous situation which, if notavoided, could result in equipment damage, data loss,

performance deterioration, or unanticipated results.

NOTICE is used to address practices not related to personalinjury.

Calls attention to important information, best practices andtips.

NOTE is used to address information not related to personalinjury, equipment damage, and environment deterioration.

General Conventions

The general conventions that may be found in this document are defined as follows.

Convention Description

Times New Roman Normal paragraphs are in Times New Roman.

Boldface Names of files, directories, folders, and users are inboldface . For example, log in as user root .

Italic Book titles are in italics .

Courier New Examples of information displayed on the screen are inCourier New.

Command Conventions



iv


6/133

The command conventions that may be found in this document are defined as follows.


Boldface The keywords of a command line are in boldface .

Italic Command arguments are in italics .

[ ] Items (keywords or arguments) in brackets [ ] are optional.

{ x | y | ... } Optional items are grouped in braces and separated byvertical bars. One item is selected.

[ x | y | ... ] Optional items are grouped in brackets and separated byvertical bars. One item is selected or no item is selected.

{ x | y | ... } * Optional items are grouped in braces and separated byvertical bars. A minimum of one item or a maximum of allitems can be selected.

[ x | y | ... ] * Optional items are grouped in brackets and separated byvertical bars. Several items or no item can be selected.

GUI Conventions

The GUI conventions that may be found in this document are defined as follows.


Boldface Buttons, menus, parameters, tabs, window, and dialog titlesare in boldface . For example, click OK .

> Multi-level menus are in boldface and separated by the ">"signs. For example, choose File > Create > Folder .

Keyboard Operations

The keyboard operations that may be found in this document are defined as follows.

Format Description

Key Press the key. For example, press Enter and press Tab .

Key 1 +Key 2 Press the keys concurrently. For example, pressing Ctrl +Alt+A means the three keys should be pressed concurrently.

Key 1 , Key 2 Press the keys in turn. For example, pressing Alt , A meansthe two keys should be pressed in turn.

Mouse Operations



v


7/133

The mouse operations that may be found in this document are defined as follows.

Action Description

Click Select and release the primary mouse button without movingthe pointer.

Double-click Press the primary mouse button twice continuously andquickly without moving the pointer.

Drag Press and hold the primary mouse button and move the pointer to a certain position.



vi


8/133

Contents

About Thi s Document.....................................................................................................................ii

1 Changes in the eNodeB Technical Description.......................................................................1

2 LTE-SAE System Architecture....................................................................................................9

3 eNodeB Functions.......................................................................................................................11

4 eNodeB Structure.........................................................................................................................134.1 Logical St ructure of BBU3900.....................................................................................................................................14

4.2 Logical St ructure of RRUs/RFUs.................................................................................................................................15

5 Environ ment Monitoring Principles........................................................................................18

6 eNodeB Synchronization Modes..............................................................................................22

7 Operatio n and Maintenance of eNodeBs................................................................................247.1 OM Modes....................................................................................................................................................................25

7.2 OM Funct ions...............................................................................................................................................................26

8 eNodeB Reliability......................................................................................................................298.1 System Reliability.........................................................................................................................................................30

8.2 Hardware Reliability.....................................................................................................................................................31

8.3 Software Reliability......................................................................................................................................................32

9 eNodeB Topologies.....................................................................................................................349.1 eNodeB T ransport Network Topologies.......................................................................................................................35

9.2 eNodeB C PRI-based Topologies..................................................................................................................................37

10 Typical Hardware Configurations of an eNodeB...............................................................4410.1 Typical Hardware Configurations and Subrack Numbers..........................................................................................45

10.2 Hardwar e Configurations of BTS3900 LTE..............................................................................................................51

10.3 Hardwar e Configurations of BTS3900A LTE............................................................................................................54

10.4 Hardwar e Configurations of BTS3900L LTE............................................................................................................57

10.5 Hardware Configurations of DBS3900 LTE..............................................................................................................60

11 Product Specifications..............................................................................................................6211.1 Technical Specifications for BBU3900......................................................................................................................63

11.2 Technical Specifications of RFUs..............................................................................................................................64

eNodeBTechnical Description Contents


vii


9/133

11.2.1 Technical Specifications of the LRFU....................................................................................................................65

11.2.2 Technical Specifications of the LRFUe...................................................................................................................68

11.2.3 Technical Specifications of the MRFU...................................................................................................................70

11.2.4 Technical Specifications of the MRFUd.................................................................................................................72

11.3 Technical Specifications of RRUs..............................................................................................................................75

11.3.1 Technical Specifications of the RRU3201..............................................................................................................77








11.3.9 Technical Specifications of the RRU3908............................................................................................................103

11.3.10 Technical Specifications of the RRU3928..........................................................................................................107

11.3.11 Technical Specifications of the RRU3929..........................................................................................................110

11.4 Engineering Specifications.......................................................................................................................................113

11.4.1 BTS3900 Engineering Specifications....................................................................................................................113

11.4.2 BTS3900L Engineering Specifications.................................................................................................................116

11.4.3 BTS3900A Engineering Specifications.................................................................................................................118

11.4.4 DBS3900 Engineering Specifications...................................................................................................................122

eNodeBTechnical Description Contents


viii


10/133

1 Changes in the eNodeB TechnicalDescription

This chapter describes the changes in the eNodeB Technical Description .

14 (2013-11-30)

This is the fourteenth official release.

Compared with issue 13 (2013-05-30) of V100R003C00, this issue does not add topics.

Compared wit h issue 13 (2013-05-30) of V100R003C00, this issue incorporates the changesdescribed in th e following table.

Topic Change Description

11.3.3 TechnicalSpecifications of theRRU3220

Changed the TMA support capability of RRU3220 to notsupported.

Compared with issue 13 (2013-05-30) of V100R003C00, this issue does not delete topics.

13 (2013-05-30)This is the thirteenth official release.


Compared with issue 12 (2013-01-24) of V100R003C00, this issue incorporates the changesdescribed in the following table.


10.1 Typical HardwareConfigurations and Subrack Numbers

Added auxiliary cabinets IBBS700D and IBBS700T.

eNodeBTechnical Description 1 Changes in the eNodeB Technical Description


1


11/133


11.2.4 TechnicalSpecifications of the

MRFUd

Modified the maximum power consumption.


12 (2013-01-24)

This is the twe lfth official releas e.

Compared wit h issue 11 (2012-10-19) of V100R003C00, this issue adds the following newsection:l 11.4 Engineering Specifications

Compared wit h issue 11 (2012-10-19) of V100R003C00, this issue incorporates the changesdescribed in th e following table.


4.2 Logical Structure of RRUs/RFUs

Changed the filter to duplexer in the logic structure of an RFmodule.


l Removed description about the BTS3900A (Ver.D1)cabinets, and renamed the BTS3900A (Ver.D2) cabinetsBTS3900A (Ver.D).

l Removed description about the DBS3900 (Ver.D1)cabinets, and renamed the DBS3900 (Ver.D2) cabinetsDBS3900 (Ver.D).

11.2.1 TechnicalSpecifications of the LRFU

l Removed description about the AWS frequency band.l Modified the maximum power consumption.

11.2.3 TechnicalSpecifications of the MRFU

Modified the receiver sensitivity when it operates in the 1800MHz frequency band.

11.2.4 Technical

Specifications of theMRFUd

l Modified the receiver sensitivity when it operates in the

1800 MHz frequency band.l Modified the maximum power consumption.


Modified the receiver sensitivity when it operates in the 700MHz frequency band (band 13).


Modified the bandwidth and maximum power consumption.



2


12/133


11.3.10 TechnicalSpecifications of the

RRU3928

Modified the receiver sensitivity


Modified the receiver sensitivity


11 (2012-10-19)

This is the elevent h official release.




11.2 TechnicalSpecifications of RFUs

Added the hybrid configuration rule for RFUs.

11.3 TechnicalSpecifications of RRUs Added the hybrid configuration rule for RRUs.

Compared wit h issue 10 (2012-09-20) of V100R003C00, this issue does not delete topics.

10 (2012-09-20)

This is the tenth official release.

Compared with issue 09 (2012-06-10) of V100R003C00, this issue adds the following newsection:l 11.1 Technical Specifications for BBU3900



7.2 OM Functions Added description about board-in-cabinet transportation.


Added the support for Ver.D cabinets.



3


13/133


11.2 TechnicalSpecifications of RFUs

Added the transmit and receive capabilities of the RFU, andthe frequency bands and RATs supported by the RFU.

11.3 TechnicalSpecifications of RRUs

Added the transmit and receive capabilities of the RRU, andthe frequency bands and RATs supported by the RRU.


Updated the weight specifications.


Added the RRU3908 V1's support for the 15 MHz bandwidth.


09 (2012-06-10)

This is the ninth official release.

Compared wit h issue 08 (2012-04-1 6) of V100R003C00, this issue does not add topics.

Compared with issue 08 (2012-04-16) of V100R003C00, this issue incorporates the changesdescribed in th e following table.


11.3 TechnicalSpecifications of RRUs

Updated the operating environment of RRUs.


Updated the output power of an RRU3841.


08 (2012-04-16)

This is the eighth official release.

Compared wit h issue 07 (2012-02-2 8) of V100R003C00, this issue adds the following newsection:l 11.3.8 Te chnical Sp ecifications of the RRU3841

Compared wit h issue 07 (2012-02-2 8) of V100R003C00, this issue incorporates the changes

described in th e following table.



4


14/133



The logical structure of time division duplex (TDD) remoteradio units (RRUs) is deleted.

9.2 eNodeB CPRI-basedTopologies

l The eNodeB CPRI-based topologies for TDD andRRU3232 common public radio interface (CPRI) portspecifications are deleted.

l The radio frequency (RF) CPRI port specifications aremodified.


Typical configurations for TDD are deleted.

11 Product Specifications l Specifications about receive (RX) sensitivity and power

consumption are added.l Specifications about radio frequency unit (RFU)

dimensions and weights are added.


07 (2012-02-28)

This is the seventh official release.




6 eNodeB SynchronizationModes

The GLONASS clock and free-running synchronizationmodes are added.

9.2 eNodeB CPRI-basedTopologies

CPRI port specifications are added.


06 (2011-11-25)

This is the sixt h official release.

Compared with issue 05 (2011-09-30) of V100R003C00, this issue adds the following newsection:l 11 Product Specifications



5


15/133



4.2 Logical Structure of RRUs/RFUs The description of an RRU and an RFU is added.

9 eNodeB Topologies The full names of LRRU and MRRU are added.


05 (2011-09-30)

This is the fifth official release.


Compared wit h issue 04 (2011-06-10) of V100R0 03C00, this issue incorporates the changesdescribed in the following table.


10.1 Typical Hardware Configurationsand Subrack Numbers

l The hardware quantities of a frequencydivision duplex (FDD) eNodeB in typicalconfigurations are modified.

l The hardware quantities of a time divisionduplex (TDD) eNodeB in typicalconfigurations are modified.

l Ver.B and Ver.C cabinets are distinguished between each other.

10.2 Hardware Configurations of BTS3900 LTE

The positions of the BTS3900 LTE componentsin typical configurations and the hardwareconfiguration descriptions are modified.

10.3 Hardware Configurations of BTS3900A LTE

The positions of the BTS3900A LTE componentsin typical configurations and the hardwareconfiguration descriptions are modified.

10.4 Hardware Configurations of BTS3900L LTE

The positions of the BTS3900L LTE componentsin typical configurations and the hardwareconfiguration descriptions are modified.

10.5 Hardware Configurations of DBS3900 LTE

The hardware configuration descriptions of theDBS3900 LTE are modified.

Hardware Configurations of DBS3900LTE TDD

The hardware configuration descriptions of theDBS3900 LTE TDD are modified.

Compared wit h issue 04 (2011-06-10 ) of V100R003C00, this issue does not delete topics.



6


16/133

04 (2011-06-10)

This is the fourth official release.


Compared with issue 03 (2011-04-15) of V100R003C00, this issue does not incorporate anychange.


03 (2011-04-15)

This is the third official release.


Compared with issue 02 (2011-03-15) of V100R003C00, this issue does not incorporate anychange.


02 (2011-03-15)

This is the sec ond officia l release.

Compared wit h issue 01 (2011-01-20) o f V100R003C00, this issue does not add topics.




Hardware quantities of a frequency division duplex (FDD)eNodeB in typical configurations are modified.

Hardware quantities of a time division duplex (TDD)eNodeB in typical configurations are modified.


01 (2011-01-20)

This is the first official release.

Compared with draft A (2010-12-15) of V100R003C00, this issue does not add topics.

Compared with draft A (2010-12-15) of V100R003C00, this issue incorporates the changesdescribed in the following table.



7


17/133



l The logical structures of FDD RRUs and RFUs are allillustrated in one figure.

l The figure showing the logical structure of TDD RRUswith 2T2R is deleted.

l The logical structures of TDD RRUs are all illustratedin one figure.

Compared with draft A (2010-12-15) of V100R003C00, this issue does not delete topics.

Draft A (2010-12-15)

This is the draft.




9 eNodeB Topologies The description of CPRI port rates is added.


Descriptions of RRU/RFU logical structures arecombined into one section.


Typical FDD/TDD configurations are updated.




8


18/133

2 LTE-SAE System ArchitectureThis chapter describes Long Term Evolution-System Architecture Evolution (LTE-SAE) systemarchitecture, including the position of eNodeBs in the system and the functions of the Network Elements (NEs) in the network.

eNodeB in the LTE-SAE System

The LTE-SAE system architecture consists of the E-UTRAN and EPC. Figure 2-1 shows thesystem architecture.

Figure 2-1 LTE-SAE system architecture

eNodeB: E-UTRAN NodeB E-UTRAN: EvolvedUTRAN

EPC: Evolved Packet Corenetwork

MME: MobilityManagement Entity

S-GW: Serving Gateway UE: User Equipment

As shown in Figure 2-1 , an eNodeB is radio access equipment in the LTE-SAE system. One or more eNodeBs constitute an E-UTRAN. An eNodeB communicates with a UE, another eNodeB,or the EPC through the Uu interface, X2 interface, or S1 interface, respectively.

eNodeBTechnical Description 2 LTE-SAE System Architecture


9


19/133

Functions of NEs

The NEs in the LTE-SAE system include eNodeBs, MMEs, and S-GWs. Table 2-1 describesthe functions of the NEs.

Table 2-1 Functions of the NEs in the LTE-SAE system

NE Function

eNodeB l Radio resource management, including radio bearer control, radioadmission control, connection mobility control, and scheduling

l Packet compression and cipheringl Routing of user plane data towards an S-GWl MME selectionl Scheduling and transmission of broadcast information and paging

messagesl Measurement and measurement reporting configuration

MME l Paging message distributionl Security controll Mobility management in idle model SAE bearer controll Ciphering and integrity protection of Non-Access Stratum (NAS)

signaling

S-GW l Termination of user plane packets that are generated for paging reasonl Support for user plane handovers caused by UE mobility

eNodeBTechnical Description 2 LTE-SAE System Architecture


10


20/133

3 eNodeB FunctionsThis chapter describes the functions of eNodeBs. As the radio access equipment in the LTE-SAE system, eNodeBs perform radio resource management, packet compression and ciphering,user plane packet routing, MME selection, and message scheduling and transmission.

Radio Resource Management

Radio resource management covers radio bearer control, admission control, mobilitymanagement, and dynamic resource allocation:

l Radio bearer control involves setup, maintenance, and release of radio bearers and resourceconfiguration for radio bearers.

l Admission control accepts or rejects radio bearer setup requests.l Mobility management involves management of radio resources for UEs in idle mode and

UEs in connected mode.l Dynamic resource allocation involves allocation and release of radio resources on the

control plane and user plane. The resources include the buffer, processes, and resource blocks.

Packet Compression and Ciphering

Packet compression and ciphering include the following functions:

l Header compression for downlink packets and header decompression for uplink packetsusing compression algorithms

l Encryption and decryption of packets using ciphering algorithms

User Plane Packet Routing

Each eNodeB provides routing of user plane packets towards an S-GW.

MME Selection

MME selection includes the following functions:

l Selection of an MME for a UE during the Attach procedure of the UE

eNodeBTechnical Description 3 eNodeB Functions


11


21/133

l Selection of an MME for a UE when the UE is in a network l Indirect determination of the route to an MME based on the information provided by the

UE when no routing information is available

Message Scheduling and TransmissionMessage scheduling and transmission include the following functions:

l Reception of paging messages and broadcast information from an MME and Operation andMaintenance (OM) messages from the Operation and Maintenance Center (OMC)

l Transmission of paging messages, broadcast information, and OM messages over the Uuinterface according to specific scheduling rules

eNodeBTechnical Description 3 eNodeB Functions


12


22/133

4 eNodeB StructureAbout This Chapter

This chapter describes the structure of an eNodeB. eNodeBs are designed based on a distributedarchitecture. Each eNodeB consists of two basic types of component: baseband unit BBU3900and Radio Frequency (RF) unit RRU or RFU.

4.1 Logical Structure of BBU3900BBU3900 consists of four logical subsystems: control, transport, baseband, and power andenvironment monitoring.

4.2 Logical S tructure of RRUs/RFUsAn remote ra dio unit (RRU) or radio frequency unit (RFU) contains logical units such as theCPRI module , transceiver (TRX), power module, power amplifier (PA), low noise amplifier (LNA), duple xer, and TX/RX switch.

eNodeBTechnical Description 4 eNodeB Structure


13


23/133

4.1 Logical Structure of BBU3900BBU3900 consists of four logical subsystems: control, transport, baseband, and power andenvironment monitoring.

Figure 4-1 shows the logical structure of BBU3900.

Figure 4-1 Logical structure of BBU3900

Control SubsystemThe functions of the control subsystem are implemented by the LTE main processingtransmission unit (LMPT).

This subsystem performs OM functions, processes signaling, and provides the system clock. Itmanages the entire eNodeB.

l The OM functions include configuration management, fault management, performancemanagement, security management, and deployment.

l The signaling involves Packet Data Convergence Protocol (PDCP) signaling on the Uuinterface and Stream Control Transmission Protocol (SCTP) signaling on the S1 and X2interfaces.

l The system clock can be one of the following types: Global Positioning System (GPS),Remote Global Positioning System (RGPS), IEEE1588 V2, synchronous Ethernet, or Clock over IP.

NOTE

To support the RGPS clock, an eNodeB must be equipped with a universal satellite card and clock unit (USCU).

Transport Subsystem

The functions of the transport subsystem are implemented by the LMPT and UTRPs, whichsupport IP over FE/GE and IP over E1/T1, respectively.

The transport subsystem performs the following functions:



14


24/133

l Provides ports for communication between the eNodeB and the EPC.l Provides the OM channel between the eNodeB and the Local Maintenance Terminal (LMT)

or M2000.l Provides ports for communication between the eNodeB and 2G/3G base stations so that

the E1/T1 transmission resources can be shared by the eNodeB and the 2G/3G base stations.

Baseband Subsystem

The functions of the baseband subsystem are implemented by LBBPs.

The baseband subsystem performs the functions for the user plane of the Uu interface, includinguplink and downlink scheduling and data processing. In addition, this subsystem provides theCommon Public Radio Interface (CPRI) for communication between BBU3900 and RF units.

l According to the indication of uplink scheduling result, the uplink processing modulereceives data over uplink channels, demodulates and decodes the data, assembles the data

into packets, and then transmits the data to the MME or S-GW through the transportsubsystem. In addition, the module performs measurements on uplink channels.

l According to the indication of downlink scheduling result, the downlink processing moduleassembles the data received from the transport subsystem into packets, encodes andmodulates the data, performs Multiple Input Multiple Output (MIMO) and OrthogonalFrequency Division Multiplex (OFDM) processing, and then transmits the signals over theCPRI interface.

l The CPRI interface is used for transmission of data between BBU3900 and RF units.

Power and Environment Monitoring Subsystem

The functions of the power and environment monitoring subsystem are implemented by theUPEU and environment monitoring units.

The power and environment monitoring subsystem performs the following functions:

l Supplies power to BBU3900.l Monitors power status of BBU3900.l Provides ports for connections to environment monitoring units and receives and forwards

signals from the environment monitoring units.

4.2 Logical Structure of RRUs/RFUsAn remote radio unit (RRU) or radio frequency unit (RFU) contains logical units such as theCPRI module, transceiver (TRX), power module, power amplifier (PA), low noise amplifier (LNA), duplexer, and TX/RX switch.

An RFU is a radio frequency unit, which is used for a macro eNodeB. RFUs modulate anddemodulate baseband signals and RF signals, process data, amplify power, and detect standingwaves.

An RRU is a remote radio unit. One or more RRUs constitute the RF part of a distributed eNodeB.RRUs modulate and demodulate baseband signals and RF signals, process data, amplify power,and detect standing waves.

Figure 4-2 shows the logical structure of RRUs and RFUs.



15


25/133

Figure 4-2 Logical structure of RRUs and RFUs

RRU3240 is designed with 2T4R, RRU3841 is designed with 4T4R, other RRUs and the LTEradio frequency unit (LRFU) are designed with 2T2R, and the multi-mode radio frequency unit(MRFU) is designed with 1T2R.

NOTE

In the preceding figures, m denotes the number of PAs, and n denotes the number of LNAs. For example,in the logical structure of the RRU with 4T4R, m and n are both equal to 4.

CPRI Module

A CPRI module performs the following functions:

l Receives downlink baseband data from BBU3900.l Transmits uplink baseband data to BBU3900.l

Forwards the data sent from the cascaded RRUs.

TRX

A TRX provides RX and TX channels.

l The TRX performs the following functions at an RX channel:

Down-converts the received signals to Intermediate Frequency (IF) signals.

Amplifies the IF signals. Performs analog-to-digital conversion.

Performs digital down-conversion.

Performs matched filtering.



16


26/133

Performs automatic gain control.l The TRX performs the following functions at a TX channel:

Performs deframing of In-phase or Quadrature (I/Q) signals on the CPRI interface.

Performs the following functions on the downlink IQ signals: filtering, digital-to-analogconversion, up-conversion, power amplification, and RF filtering. Reports TX power. Provides overload protection for PAs. Shuts down and opens the TX channel. Provides the closed-loop power control function. Filters downlink spread spectrum signals.

Power Module

A power module converts the input power into the power required by an RRU or RFU.

PA and LNA

A PA amplifies the low-power RF signals received from the TRX.

An LNA amplifies signals received from antennas.

Duplexer

A duplexer isolates the RX and TX signals so that signals can be received and transmittedsynchronously.



17


27/133

5 Environment Monitoring PrinciplesThis chapter describes environment monitoring principles for eNodeBs. Environmentmonitoring detects the following environmental conditions of an eNodeB: temperature,humidity, water damage, smoke, unauthorized access, and power distribution faults. Toimplement environment monitoring, the eNodeB is equipped with environment monitoringdevices and configured with external environment alarms, including Boolean alarms and anEMUA alarm.

Ports on a UPEUThe Universal Power and Environment Interface Unit (UPEU) is a mandatory board of aneNodeB. It is configured in slot 18 or 19 in BBU3900. A UPEU provides two EXT-ALM portsand two MON ports for connections to environment monitoring devices. The ports are described

as follows:l Each EXT-ALM port supports four Boolean inputs. The two ports are used for connections

to Boolean signal sensors and to dry contacts in a cabinet. The EXT-ALM ports can be connected to the environment monitoring ports, including

the alarm port and in-position signal port, on a +24 V DC/DC power subrack in aBTS3900 cabinet. In this way, PSU status is monitored.

The EXT-ALM ports can also be used for eight Boolean inputs from sensors, such asa door status sensor and water sensor. In this solution, data configuration is required.For example, door status and water damage alarms must be defined for the eNodeB.

l Each MON port supports one RS485 monitoring signal input. The two ports are used for

connections to environment monitoring devices inside and outside a cabinet. A MON port can be connected to an environment monitoring device in a cabinet. The

type of the device varies depending on the type of the cabinet.

For example, an APM30H cabinet is installed with a Central Monitoring Unit type A(CMUA) for centralized monitoring of environment in the APM30H cabinet. TheCMUA provides ports for connections to the door status sensor and smoke sensor andalso provides a port used for three Boolean signal inputs.

Signals of environmental alarms detected by the sensors connected to the CMUA are processed directly by the LMPT. Therefore, no data configuration is required.

A MON port can also be connected to an Environment Monitoring Unit type A (EMUA),which is an environment monitoring device outside an APM30H cabinet, for centralizedmonitoring of environment outside the APM30H cabinet.

eNodeBTechnical Description 5 Environment Monitoring Principles


18


28/133

The EMUA is 1 U high. It can be installed in a 19-inch rack with its depth exceeding300 mm or in a 19-inch cabinet.

The EMUA provides dedicated ports for connections to sensors such as door status,smoke, water, temperature, and humidity sensors. In addition, the EMUA provides

extended ports for 32 Boolean and analog signal inputs. If the EMUA is used to monitor environment outside a cabinet, data configuration is required. If the dedicated ports onthe EMUA are insufficient for environment monitoring, the extended ports can be usedand related data configuration is required.

The alarm monitoring devices connected to the UPEU (such as dry contacts, sensors, and theEMU) are collectively called peer alarm devices in the subsequent sections.

Connections to EXT-ALM Ports

The type of the cable connected to an EXT-ALM port varies depending on the type of the peer

alarm device.l If the peer alarm device is a +24 V DC/DC power subrack in a cabinet, two signal cables

are required. For details about how to install the cables, see the BTS3900 (Ver.B) LTE Installation Guide or BTS3900 (Ver.C) Installation Guide .

Connect one end of an in-position signal cable for the PSU (DC/DC) to the EXT-ALM0 port and the other end to the in-position signal port on the power subrack.

Connect one end of a monitoring signal cable for the PSU (DC/DC) to the EXT-ALM1 port and the other end to the alarm port on the power subrack.

l If the peer alarm devices are Boolean signal sensors, add a terminal to one end of a BBUalarm cable by referring to Table 5-1 , connect the terminal to a Boolean signal sensor, andthen connect the RJ45 connector at the other end of the cable to the EXT-ALM0 or EXT-ALM1 port.

Table 5-1 Pin assignment for wires of the BBU alarm cable

AlarmPort

X1 End X2 End WireColor

Description PinAssignment

EXT-ALM0

X1.1 X2.1 Orange andwhite

Boolean input 1+ Twisted pair

X1.2 X2.2 Orange Boolean input 1-(GND)

X1.3 X2.3 Green andwhite


X1.6 X2.6 Green Boolean input 2-(GND)

X1.5 X2.5 Blue andwhite


X1.4 X2.4 Blue Boolean input 3-

(GND)



19


29/133

AlarmPort

X1 End X2 End WireColor

Description PinAssignment

X1.7 X2.7 Brown and

white


X1.8 X2.8 Brown Boolean input 4-(GND)

EXT-ALM1

X1.1 X2.1 Orange andwhite


X1.2 X2.2 Orange Boolean input 5-(GND)

X1.3 X2.3 Green andwhite


X1.6 X2.6 Green Boolean input 6-(GND)

X1.5 X2.5 Blue andwhite


X1.4 X2.4 Blue Boolean input 7-(GND)

X1.7 X2.7 Brown andwhite


X1.8 X2.8 Brown Boolean input 8-(GND)

The EXT-ALM0 port is connected to dry contacts 0 to 3, and the EXT-ALM1 port is connectedto dry contacts 4 to 7.

Connections to MON PortsThe UPEU can be connected to either a unit in a cabinet or an EMUA outside a cabinet.

If the UPEU needs to be connected to a unit in a cabinet, cable connections vary depending onthe type of the cabinet.

l In an APM30H cabinet, connect one end of a monitoring signal cable between the CMUAand the BBU to the MON1 port on the UPEU and the other end of the cable to the COM_IN

port on the CMUA. For details about how to install the cable, see the BBU3900 InstallationGuide .

l In an RFC, connect one end of a monitoring signal cable between the CMUA and the BBUto the MON0 port on the UPEU and the other end of the cable to the COM_IN port on theCMUA. For details about how to install the cable, see the BTS3900A (Ver.B) LTE

Installation Guide or BTS3900A (Ver.C) Installation Guide .l In a BTS3900 cabinet, connect one end of a monitoring signal cable for the PMU to the

MON0 port on the UPEU and the other end of the cable to the COM port on the PMU. In



20


30/133

addition, connect one end of a monitoring signal cable for the FAN unit to the MON1 porton the UPEU and the other end of the cable to the COM IN port on the FAN unit. For detailsabout how to install the cable, see the BTS3900 (Ver.B) LTE Installation Guide or BTS3900(Ver.C) Installation Guide .

If the UPEU needs to be connected to an EMUA outside a cabinet, connect one end of an RS485monitoring signal cable to an unused MON port on the UPEU and the other end of the cable toa 2-input RS485 port on the EMUA.

NOTE

If both MON ports on the UPEU are in use, configure a Universal Environment Interface Unit (UEIU) in theeNodeB. Then, connect one end of an RS485 monitoring signal cable to the MON0 port on the UEIU and theother end of the cable to a 2-input RS485 port on the EMUA.



21


31/133

6 eNodeB Synchronization ModesThis chapter describes the clock synchronization modes of eNodeBs. eNodeBs supportsynchronization with the following clocks: GPS/RGPS clock, GLONASS clock, IEEE1588 V2clock, Clock over IP, synchronous Ethernet, 1 PPS+TOD clock, BITS clock, and E1/T1 lineclock. If an eNodeB fails to obtain clock signals, it works in free-run mode for a certain periodof time.

Synchronization refers to maintenance of the relation that at a valid point of time, the phase error or frequency error between two or more signals stays within the specified range. There are twotypes of synchronization: frequency synchronization and time synchronization.

l Frequency synchronization means that the frequency of a signal is the same as the referencefrequency but the origin of the timescale for the signal does not need to be the same as that

for the reference clock.l Time synchronization is also referred to as time-of-day synchronization, where the origin

of the timescale for a signal needs to be synchronized with the Universal Time Coordinated(UTC). Therefore, time synchronization implies synchronization in absolute time. TheUTC time is a universal timing standard, in which the atomic clock is maintained accuratelyto ensure time synchronization across the world, with the precision to microseconds.

The subsequent sections describe the preceding reference clocks. For details about clock synchronization, see the Synchronization Feature Parameter Description .

GPS/RGPS Clock

Synchronization with a GPS or RGPS clock requires that each eNodeB be equipped with a GPSor RGPS receiver. Using the receiver, the eNodeB receives GPS or RGPS clock signals with the

precision to microseconds. In synchronization with a GPS or RGPS clock, both frequencysynchronization and time synchronization are applicable. To implement synchronization withan RGPS clock, the eNodeB must be equipped with a USCU.

GLONASS Clock

If an eNodeB synchronizes with the GLONASS clock, it achieves synchronization by obtainingclock signals from a GLONASS receiver. The GLONASS clock supports both frequencysynchronization and time synchronization, with a precision to microseconds. To synchronizewith the GLONASS clock, an eNodeB must be equipped with a USCU board.

eNodeBTechnical Description 6 eNodeB Synchronization Modes


22


32/133

IEEE1588 V2 Clock

IEEE1588 defines the Precision Time Protocol (PTP), which targets synchronization of clocksin the Ethernet, with the precision to microseconds. In synchronization with an IEEE1588 V2clock, both frequency synchronization and time synchronization are applicable.

Clock over IP

Clock over IP is a Huawei proprietary frequency synchronization technology, in whichfrequency synchronization packets are transmitted over IP. Clock-over-IP signals are transmittedto eNodeBs based on a server/client architecture. In synchronization with a clock over IP, onlyfrequency synchronization is applicable, with the frequency accuracy lower than 0.05 ppm.

Synchronous Ethernet

The synchronous Ethernet technology has the basic principles that a downstream node traces

the upstream clock by recovering clock signals from the serial data bit streams received at the physical layer. In synchronous Ethernet, only frequency synchronization is applicable, with thefrequency accuracy lower than 0.05 ppm.

1 PPS+TOD Clock

In synchronization with a 1 PPS+TOD clock, the eNodeB obtains 1 PPS signals and Time of Day (TOD) signals to implement time synchronization. The 1 PPS signals are used for timesynchronization. The TOD signals are used to transmit the time information, type of the referenceclock, and working status of the reference clock.

BITS ClockIn synchronization with a BITS clock, the eNodeB is connected to a BITS synchronizationnetwork through the BITS clock card in the eNodeB to obtain frequency synchronization signals.After phase lock and frequency division, the main clock unit in the eNodeB converts thesynchronization signals into various types of clock signals required for the eNodeB. Toimplement synchronization with a BITS clock, the eNodeB must be equipped with a USCU.

E1/T1 Line Clock

In synchronization with an E1/T1 line clock, the eNodeB obtains frequency synchronizationsignals from the physical layer of E1/T1 lines. This clock synchronization mode is applicablewhen S1 data is transmitted over an E1/T1 network. To implement synchronization with an E1/T1 line clock, the eNodeB must be equipped with a UTRP.

Free-Run

Without an external clock source, a base station continues to work for at least 90 days in free-run mode.

eNodeBTechnical Description 6 eNodeB Synchronization Modes


23


33/133

7 Operation and Maintenance of eNodeBsAbout This Chapter

This chapter describes operation and maintenance of eNodeBs. The operation and maintenance(OM) system of eNodeBs manages, monitors, and maintains the software, hardware, andconfiguration data of the eNodeBs. In addition, the OM system provides various OM modes tomeet requirements.

7.1 OM ModesThis section describes the operation and maintenance (OM) modes for eNodeBs.

7.2 OM Func tionsThis section d escribes the OM functions of eNodeBs, covering configuration management, faultmanagement, performance management, security management, software management,deployment management, equip ment management, and inventory management.

eNodeBTechnical Description 7 Operation and Maintenance of eNodeBs


24


34/133

7.1 OM ModesThis section describes the operation and maintenance (OM) modes for eNodeBs.

eNodeBs support both local and remote operation and maintenance.

l In local OM mode, maintenance personnel use the Local Maintenance Terminal (LMT) tooperate and maintain a single eNodeB.

l In remote OM mode, maintenance personnel use the M2000 or LMT to operate andmaintain eNodeBs in a centralized manner in the operation and maintenance center (OMC).

Figure 7-1 OM system of eNodeBs

As shown in Figure 7-1 , the OM system of eNodeBs consists of the following elements:

l LMT: is mainly used to assist eNodeB deployment, identify faults, and rectify faults locally.l M2000: is Huawei centralized OM system, which consists of the M2000 server and the

M2000 client. M2000 can be connected to eNodeBs of different models and versionsthrough an OM network for remote centralized operation and maintenance. This mode isrecommended when eNodeBs communicate with M2000 properly.

l eNodeB: is the object of the operation and maintenance.

The required OM software, as described in Table 7-1 , must be installed on maintenanceterminals for operation and maintenance of eNodeBs.



25


35/133

Table 7-1 OM software

Software Function

iManager M2000 l Topology managementl Fault managementl Configuration managementl Performance managementl Security managementl Software and hardware management

LMT l Man-machine language (MML)command execution

l Alarm managementl Batch processingl Tracing managementl Performance monitoringl Self-check managementl Software managementl Comprehensive maintenance and

commissioning

7.2 OM FunctionsThis section describes the OM functions of eNodeBs, covering configuration management, faultmanagement, performance management, security management, software management,deployment management, equipment management, and inventory management.

Configuration Management

Configuration management includes data configuration, query, export, backup and restore, andconfiguration synchronization with M2000.

The data configuration is based on Managed Objects (MOs) of the following categories: device,transport, and service. These categories are independent of each other. Generally, modificationsof the service configuration do not require modifications of the device configuration, andmodifications of the device configuration do not require modifications of the serviceconfiguration either.

Fault Management

Fault management includes fault detection, fault isolation and self-healing, alarm reporting, andalarm correlation. The faults might be related to hardware, environment, software, transmission,cells, and different types of services in cells.



26


36/133

l Fault isolation and self-healing bring the following advantages: (1) prevents a fault in some part of an eNodeB from affecting the entire eNodeB; (2) re-establishes a cell of lower specifications to minimize the impact of the fault on services.

l The alarm correlation function enables the system to report only the alarm indicating the

root fault and the ultimate impact on services though there are chains of problems caused by the root fault.

Performance Management

Performance management includes the periodic control on eNodeB performance measurementand the collection, storage, and reporting of performance statistics.

eNodeBs collect performance statistics every 15 or 60 minutes. If communication between aneNodeB and the mobile Element Management System (EMS) fails, the eNodeB can store amaximum of three days of performance measurement results. The performance measurementcovers eNodeB-level and cell-level performance, neighboring cells, transmission, standardinterfaces, and the device usage.

eNodeBs support real-time monitoring of Key Performance Indicators (KPIs) at intervals of oneminute, which helps detect and identify faults in time.

Security Management

Security management provides the eNodeB authentication and access control functions, whichinclude user account management, rights management, login management, identityauthentication, and operation authentication.

In addition, security management involves security control on the channels between eNodeBsand an EMS. The channels support encryption using Secure Socket Layer (SSL) or IP Security(IPSec).

Security management provides network- and user-level security service. It provides thefollowing functions:l Encryption: encryption of important user informationl Authentication: management of user accounts and authentication of usersl Access control: control of operation accessl Security protocol: support for SSL and IPSec

Software ManagementSoftware management includes software version management, software version upgrade, and

patch management.

l Software version management involves query, backup, and restore of software versions.l Software version upgrade can be performed on a batch of eNodeBs remotely. With the one-

click upgrade wizard provided by M2000, users can perform health checks before and after the upgrade and back up, download, and activate the software. During this process, userscan check the upgrade status and results. eNodeBs support automatic updates of configurations during upgrades, and users only need to follow the instructions in theupgrade wizard. In addition, eNodeBs support rapid version rollback by running a singlecommand, reducing the impact of upgrade failures on the system.



27


37/133

l Patch management includes query, download, loading, activation, deactivation, rollback,and removal of patches. Installing patches does not affect system services.

Deployment Management

The eNodeB deployment solutions include board-ready transportation, automatic discovery of eNodeBs, initial configuration by using a USB disk, and remote deployment. These solutionsgreatly reduce the workload and efforts of field installation personnel. No computer is required.The personnel only need to install the hardware.

l Board-in-cabinet transportation indicates that base stations come with RFUs, PMUs, PSUs,and BBU3900s installed and with cables laid. Board-in-cabinet transportation shortensonsite hardware installation duration.

l With the automatic discovery of the eNodeB, users do not need to set the IP addresses of the eNodeB and EMS.

l Users can download software and data of an eNodeB from a USB disk, thereby saving timeespecially when the bandwidth of transmission between the eNodeB and the EMS isinsufficient.

l During remote deployment, software commissioning is performed in the Operation andMaintenance Center (OMC) rather than on site. Customers can perform acceptance testson the eNodeB deployment in the OMC.

NOTE

The security of the USB port is ensured by encryption.

Equipment Management

Equipment management includes data configuration, status management, and fault detectionand handling for all the devices in an eNodeB. On the device panel, users can view the devicestatus and perform blocking, reset, and switchover.

Inventory Management

Inventory management includes collection and reporting of the inventory information abouteNodeBs. With inventory management, users can manage network equipment (NE) assets in theOMC in a centralized manner.



28


38/133

8 eNodeB ReliabilityAbout This Chapter

This chapter describes eNodeB reliability, which includes system reliability, hardwarereliability, and software reliability.

8.1 System ReliabilitySystem reliability is ensured by using the intra-board baseband resource pool, LMPT coldredundancy, and RRU channel cross-connection under MIMO.

8.2 Hardware Reliability

Hardware rel iability is ensured by the anti-misinsertion design of boards, overtemperature protection, reliable power supply, and surge protection design.

8.3 Software ReliabilitySoftware reli ability is ensured by the redundancy of important files and data and the powerfulerror toleranc e of software.

eNodeBTechnical Description 8 eNodeB Reliability


29


39/133

8.1 System Reliability

System reliability is ensured by using the intra-board baseband resource pool, LMPT coldredundancy, and RRU channel cross-connection under MIMO.

Intra-Board Baseband Resource Pool

Intra-board b aseband res ource pool is designed to enable dynamic allocation of basebandresources based on the specifications and load status of an LBBP. This increases the usage of

baseband resources and improves system reliability.

The functions of the baseband resource pool are as follows:

l If all resources of an LBBP are used to serve a single cell, users are allocated different baseband resources in a fair manner based on the baseband load on the LBBP.

l Full redundancy of intra- or inter-cell baseband resources is achieved. When some basebandresources are unavailable, the associated services can be diverted to other available

baseband resources. In this way, the services in the cell can be restored.

LMPT Cold Redundancy

Each eNodeB supports LMPT cold redundancy, in which two LMPTs in BBU3900 work inactive/standby mode. When the active LMPT experiences a major fault or a user runs theswitchover command, an active/standby switchover is performed automatically or manually,respectively.

LMPT cold redundancy prevents system collapse caused by LMPT failures and therefore ensuressystem reliability of eNodeBs. An active/standby switchover, however, interrupts eNodeBservices for less than three minutes.

RRU Channel Cross-Connection Under MIMO

RRU channel cross-connection under MIMO is implemented by cross-connections of RF jumpers between RRUs/RFUs and antennas and data switching in the connected LBBP. Thisfunction improves reliability of the entire network with no requirement for additional hardware.It partially achieves self-healing, preventing permanent failures to provide services in cellscaused by faults in a single RRU or RFU.

This function is applicable in scenarios where three sectors are configured on three 2T2R RFunits. When an RRU or RFU serving a sector fails, the sector is degraded from MIMO to SingleInput Single Output (SISO), preventing total service failure in the entire sector. At the sametime, another sector using the RRU or RFU is also degraded from MIMO to SISO. After thefault of the RRU or RFU is rectified, the sectors change from SISO back to MIMO automatically.In this way, self-healing is achieved.

Figure 8-1 shows the cable connections between RRUs and antennas and data streams. Thecable connections and service data flows for RFUs are the same as those for RRUs.



30


40/133

Figure 8-1 Cross-connections between RRUs and antennas under MIMO and data streams

l In the uplink as shown in Figure 8-1 , the CPRI ports receive data from RRU 0 and RRU

1. After user plane data of sector 0 is separated from data of the other sectors, the user planedata of sector 0 is sent to the module in the LBBP that processes data of sector 0.

l In the downlink as shown in Figure 8-1 , user plane data of sector 0 in the LBBP is sentthrough different CPRI ports to RRU 0 and RRU 1.

l If RRU 0 shown in Figure 8-1 is faulty, user plane data of sector 0 can be exchangedthrough RRU 1.

8.2 Hardware ReliabilityHardware reliability is ensured by the anti-misinsertion design of boards, overtemperature

protection, reliable power supply, and surge protection design.

Anti-misinsertion Design of Boards

When a board of one type is inserted into a slot for another type of board, the board cannotconnect to the backplane. This protects the equipment from damage.



31


41/133

Overtemperature Protection

When the temperature near the PA in an RF unit of an eNodeB is too high, the eNodeB generatesovertemperature alarms and immediately shuts down the PA. This protects PA from damage

caused by overtemperature.

Reliable Power Supply

The reliable power supply is achieved using the following techniques:l Support for wide-range voltages and surge protectionl Power failure protection for programs and datal Protection of power supply against overvoltage, overcurrent, and reverse connection of

positive and negative poles on boards

Surge Protection DesignSurge protection is applied to AC and DC power ports and various input and output signal portssuch as E1/T1 and FE/GE ports of eNodeBs.

8.3 Software ReliabilitySoftware reliability is ensured by the redundancy of important files and data and the powerfulerror tolerance of software.

RedundancyeNodeBs provide the redundancy function for important files and data, such as software versionsand data configuration files, to ensure proper operation of the eNodeBs when errors occur inthese files and data.

l Redundancy of software versions: An eNodeB stores software versions, including theBootROM version, in different areas to provide redundancy. If the active version isabnormal, the eNodeB switches to the backup version.

l Redundancy of data configuration files: An eNodeB stores data configuration files indifferent areas to provide redundancy. If the current file is damaged, the eNodeB cancontinue working properly by loading the backup file.

l Redundancy of boards: Two boards of the same type can work in active/standby mode.When the active board fails or is faulty, the standby board takes over, ensuring proper operation of the eNodeB.

Error Tolerance

When software errors occur, eNodeBs will not collapse, because of their self-healing capability.The software error tolerance covers the following aspects:

l Scheduled check of key resources: eNodeBs perform occupancy check on softwareresources. If resource hang-up occurs in an eNodeB due to software errors, the eNodeBcan release the unavailable resources in time and export logs and alarms.



32


42/133

l Task monitoring: eNodeBs monitor the running status of every task for all types of errorsand faults, if any. When an error or a fault occurs in a task, an alarm is reported and self-healing measures are taken to restore the task.

l Data check: eNodeBs perform scheduled or event-triggered data consistency checks and

restore data consistency selectively or preferentially. In addition, eNodeBs generate relatedlogs and alarms.

l Watchdog: eNodeBs detect system faults through the software and hardware watchdogs.When an error occurs in an eNodeB, the eNodeB automatically resets to restore itself to anormal running status.



33


43/133

9 eNodeB TopologiesAbout This Chapter

This chapter describes the topologies on the S1 interface, topologies on the common public radiointerface (CPRI), and CPRI port specifications.

9.1 eNodeB Transport Network TopologieseNodeBs support the star, chain, and tree topologies on IP networks.

9.2 eNodeB CPRI-based TopologieseNodeBs sup port various topologies on the common public radio interface (CPRI): remote radio

units (RRUs) support the star, chain, hot backup ring, intra-board cold backup ring, and inter- board cold ba ckup ring topologies; radio frequency units (RFUs) support the star topology. Inaddition to to pologies, CPRI specifications cover the number of CPRI ports on a board or radiofrequency (R F) module, CPRI data rate, cascading capability, and maximum distance betweena baseband u nit (BBU) and an RF module.

eNodeBTechnical Description 9 eNodeB Topologies


34


44/133

9.1 eNodeB Transport Network Topologies

eNodeBs support the star, chain, and tree topologies on IP networks.An eNodeB communicates with a mobility management entity (MME) or serving gateway (S-GW) through an S1 interface based on E1/T1 or FE/GE transmission. (FE is short for fastEthernet, and GE is short for gigabit Ethernet.) The S1 interface supports the star, chain, andtree topologies, as shown in Figure 9-1 .

Figure 9-1 Topologies on the S1 interface

Table 9-1 describes usage scenarios and characteristics of the preceding topologies.



35


45/133

Table 9-1 Usage scenarios and characteristics of the topologies

Topolog y

Usage Scenario Advantage Disadvantage

Star

The star topology is themost common topologyand is applicable todensely populated areas.

l Each eNodeB isdirectly connected toan MME or S-GWthrough a transportnetwork. This simpletopology features easyengineering,maintenance, andcapacity expansion.

l Each eNodeB directlyexchanges data with anMME or S-GW.Signals travel throughfew nodes, andtherefore network reliability is high.

The star topology requiresmore transport resources thanthe other topologies.

Chain

The chain topology isapplicable to belt-shaped and sparsely

populated areas, such asareas along highwaysand railways.

This topology helps reduceexpenditure ontransmission equipment,engineering, and leasedtransmission cables.

l Signals travel throughmany nodes, which lowersnetwork reliability.

l Each lower-level eNodeBoccupies sometransmission bandwidth of its upper-level eNodeB.Reliability of the upper-level eNodeB affectsoperation of the lower-level eNodeB.

l The number of levels in achain topology cannotexceed five.



36


46/133

Topolog y

Usage Scenario Advantage Disadvantage

Tree

The tree topology isapplicable to areas withcomplicated network architecture, sitedistribution, andsubscriber distribution,for example, hot spotareas in whichsubscribers are widelydistributed.

This topology helps reduceexpenditure ontransmission equipment,engineering, and leasedtransmission cables.

l Signals travel throughmany nodes, which lowersnetwork reliability.

l Each lower-level eNodeBoccupies sometransmission bandwidth of its upper-level eNodeB.Reliability of the upper-level eNodeB affectsoperation of the lower-level eNodeB.

l The number of levels in atree topology cannotexceed five.

9.2 eNodeB CPRI-based TopologieseNodeBs support various topologies on the common public radio interface (CPRI): remote radiounits (RRUs) support the star, chain, hot backup ring, intra-board cold backup ring, and inter-

board cold backup ring topologies; radio frequency units (RFUs) support the star topology. Inaddition to topologies, CPRI specifications cover the number of CPRI ports on a board or radiofrequency (RF) module, CPRI data rate, cascading capability, and maximum distance betweena baseband unit (BBU) and an RF module.

CPRI-based Topologies

On the CPRI interface, eNodeBs support the star, chain, and ring topologies.

Figure 9-2 shows the star topology.



37


47/133

Figure 9-2 Star

The star topology has the following advantages:

l Transmission reliability is high. When an RRU/RFU or an optical cable is faulty, only therelated sector is affected.

l This topology is easy. Installation and maintenance are convenient.

The disadvantage is that the star topology requires a larger number of optical cables than other topologies.

Figure 9-3 shows the chain topology.

Figure 9-3 Chain

The chain topology helps reduce expenditure on transmission equipment.

The chain topology has the following disadvantages:

l The number of cascading levels and cascading distances are restricted.l RRUs working in different modes cannot be cascaded.



38


48/133

l Faults in an upper-level RRU may affect the operation of its lower-level RRUs.

NOTE

RFUs do not support the chain topology.

Ring topologies are classified into the following types: hot backup ring, intra-board cold backupring, and inter-board cold backup ring. Figure 9-4 , Figure 9-5 , and Figure 9-6 show thesetopologies respectively.

Figure 9-4 Hot backup ring

In the hot backup ring topology, two CPRI links transmit identical service data, but the LTE baseband processing unit (LBBP) where the cell is established and the RRU process data on onelink only. If a CPRI port is faulty, services are switched over to the other CPRI link, with amaximum interruption time of 500 ms. If the LBBP where the cell is established is faulty, thecell is reestablished on the other LBBP, with a maximum service interruption time of 20s.

NOTE

The hot backup ring topology has the following constraints:l Only ports 0, 1, and 2 on the two LBBPs can be used in this topology.l The two LBBPs are installed in two slots among slots 0, 1, 2, and 3 in the BBU. If one is installed in slot 0,

the other can be installed only in slot 2 or 3.l

If the two LBBPs are installed in slots 2 and 3 in the BBU, a maximum of three rings are supported betweenthe LBBPs. In other situations, only one ring is supported.



39


49/133

Figure 9-5 Intra-board cold backup ring

In the intra-board cold backup ring topology, if a CPRI port is faulty, the cell is reestablished,with a service interruption time shorter than 20s.

Figure 9-6 Inter-board cold backup ring

In the inter-board cold-backup ring topology, if a CPRI port or LBBP is faulty, the cell isreestablished on the LBBP or the other LBBP, with a service interruption time shorter than 20s.

The advantage of ring topologies is that they are a redundancy type of the chain topology andtherefore provide higher transmission reliability.

Ring topologies have the following disadvantages:

l The number of cascading levels and cascading distances are restricted.l RRUs working in different modes cannot be cascaded.l Faults on the forwarding link of an upper-level RRU affect the operation of its lower-level

RRUs.



40


50/133

NOTE

RFUs do not support the ring topologies.

Specifications of CPRI Ports

The number of cells supported varies according to CPRI data rates, as listed in Table 9-2 .

Table 9-2 CPRI data rate and the number of cells supported

CPRIDataRate(Gbit/s)

Number of Cells Supported (4 x 4MIMO)

Number of Cells Supported (2 x 2MIMO)

1.25 Due to the limited transmission bandwidth of CPRI ports, a 4x4 MIMO

cell is not recommended.

1

2.5 1 if the cell bandwidth is less than or equal to 10 MHz

l 2 if the cell bandwidth is less thanor equal to 10 MHz

l 1 if the cell bandwidth is 15 MHz or 20 MHz

4.9 l 2 if the cell bandwidth is less thanor equal to 10 MHz


l 4 if the cell bandwidth is less thanor equal to 10 MHz


Table 9-3 lists the specifications of CPRI ports on different LBBPs.

Table 9-3 Specifications of CPRI ports on LBBPs

Board Number of CPRIPorts

CPRI Data Rate(Gbit/s)

Topology

LBBPc 6 1.25, 2.5, or 4.9 Star, chain, or ring

Table 9-4 lists the specifications of CPRI ports on different RF modules.

Table 9-4 Specifications of CPRI ports on RF modules

Module

Numberof CPRIPorts

CPRI DataRate (Gbit/s)

Topology Cascading Levels MaximumDistancefrom theBBU (km)

LRFU 2 1.25 or 2.5 Star N/A N/A



41


51/133

Module

Numberof CPRIPorts

CPRI DataRate (Gbit/s)

Topology Cascading Levels MaximumDistancefrom the

BBU (km)LRFUe

2 1.25, 2.5, or 4.9 Star N/A N/A

MRFU V2

2 1.25 or 2.5 Star N/A N/A

MRFUd

2 1.25, 2.5, or 4.9 Star N/A N/A

RRU3201

2 1.25 or 2.5 Star, chain,or ring

l Three levels aresupported if thecell bandwidth isless than or equal to 5 MHz.

l Two levels aresupported if thecell bandwidth is10 MHz.

l Cascading is notrecommended if the cell

bandwidth isgreater than or equal to 15MHz.

20

RRU3203


20

RRU3220


20

RRU3221

2 1.25, 2.5, or 4.9 Star, chain,or ring

20

RRU3222


20

RRU3808

2 1.25 or 2.5 Star, chain,or r

Documents

ENodeB Technical Description(V100R003C00_14)(PDF)-En