31013229-bts312 user manual
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Part 1 System Description
Table of Contents i.........................................................................................
Chapter 1 An Introduction to BTS312 1-1..........................................................
1.1 System Overview 1-1..............................................................................1.2 System Characteristics 1-2.....................................................................
1.2.1 Integrated RF Component Technology 1-2....................................
1.2.2 Mature RF Technology 1-2.............................................................
1.2.3 Advanced E-Abis Technology 1-2..................................................
1.2.4 Powerful O&M Functions 1-3..........................................................
1.3 Application Merits 1-3..............................................................................
1.3.1 Wide Coverage 1-3.........................................................................
1.3.2 Expenditure Reduction 1-4.............................................................
1.3.3 Smooth Evolution 1-4.....................................................................
1.3.4 Multiple Transmission Modes 1-4...................................................
1.4 Structure Overview 1-4...........................................................................
1.4.1 Logical Structure 1-4.......................................................................
1.4.2 Software Structure 1-6....................................................................
1.4.3 Cabinet Structure 1-7......................................................................
1.5 Main Functions 1-8..................................................................................
1.5.1 Basic Software Relative Functions 1-8...........................................
1.5.2 Basic Hardware Relative Functions 1-9..........................................
1.6 Technical Indices 1-9..............................................................................
Chapter 2 Hardware Architecture 2-1.................................................................
2.1 Overview 2-1...........................................................................................
2.2 TRX/CDU Frame 2-3...............................................................................
2.2.1 CDU 2-3..........................................................................................
2.2.2 EDU 2-4..........................................................................................
2.2.3 ECDU 2-5.......................................................................................
2.2.4 SCU 2-6..........................................................................................
2.2.5 TRX 2-6..........................................................................................2.2.6 PBU 2-10..........................................................................................
2.3 Common Resource Frame 2-12................................................................
2.3.1 PSU 2-12..........................................................................................
2.3.2 PMU 2-12..........................................................................................
2.3.3 TMU 2-14..........................................................................................
2.3.4 TES 2-17...........................................................................................
2.3.5 ASU 2-18..........................................................................................
2.3.6 ABB 2-20..........................................................................................
2.3.7 ABA 2-21..........................................................................................2.4 Other Parts of the Cabinet 2-21................................................................
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2.4.1 TDU 2-21..........................................................................................
2.4.2 FMU 2-23..........................................................................................
2.4.3 Switch Box 2-24................................................................................
2.4.4 Fan Box 2-24....................................................................................
2.4.5 Air Box 2-25......................................................................................
2.5 Antenna and Feeder System 2-25............................................................
2.5.1 Antenna 2-25....................................................................................
2.5.2 Feeder 2-27......................................................................................
2.5.3 Lightning Arrester 2-27.....................................................................
2.5.4 Tower-top Amplifier (Optional) 2-27..................................................
2.6 Power Supply System 2-28.......................................................................
2.6.1 Overview 2-28...................................................................................
2.6.2 Overall Structure 2-30.......................................................................
2.6.3 Technical Specifications 2-32...........................................................
2.7 Environment Monitoring System 2-36.......................................................
2.7.1 Outlook of Environment Monitoring instrument 2-36........................
2.7.2 Function Provided by Environment Monitoring Instrument 2-37.......
2.7.3 Environment Monitoring Instrument Inputs 2-37...............................
2.7.4 Alarm Indicators 2-38........................................................................
2.7.5 Executing Devices 2-38....................................................................
2.7.6 Communication 2-39.........................................................................
2.8 Lightning Protection System 2-39.............................................................2.8.1 Lightning Protection for DC Power Supply 2-40...............................
2.8.2 Lightning Protection for AC Power Supply 2-42...............................
2.8.3 Lightning Protection for Trunk Cables 2-43......................................
Chapter 3 Software Architecture 3-1..................................................................
3.1 Overview 3-1...........................................................................................
3.2 Signaling Control Processing (SCP) Program 3-2..................................
3.3 Baseband Signal Processing Program 3-4.............................................
3.4 Operation and Maintenance Program 3-5...............................................
Chapter 4 External Interfaces 4-1.......................................................................4.1 Abis Interface 4-1....................................................................................
4.1.1 Introduction 4-1...............................................................................
4.1.2 Physical Layer 4-6..........................................................................
4.1.3 Data Link Layer 4-7........................................................................
4.1.4 Layer 3-Traffic Management 4-8....................................................
4.1.5 Layer 3-Operation and Maintenance 4-12........................................
4.2 Um Interface 4-14.....................................................................................
4.2.1 Introduction 4-14...............................................................................
4.2.2 Interface Protocol Model 4-15...........................................................
4.2.3 Physical Layer 4-15..........................................................................
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4.2.4 Data Link Layer 4-20........................................................................
4.2.5 Signaling Layer 4-23.........................................................................
Chapter 5 Functions and Performance 5-1........................................................
5.1 Networking Functions 5-1.......................................................................
5.1.1 E1 Networking 5-1..........................................................................
5.1.2 SDH Networking 5-3.......................................................................
5.1.3 Networking for Satellite Transmission 5-4......................................
5.2 Main RF Functions 5-6............................................................................
5.3 Baseband Processing 5-8.......................................................................
5.3.1 Channel Types Supported 5-8........................................................
5.3.2 Channel Combinations Supported 5-9............................................
5.4 Signaling Processing 5-9........................................................................
5.5 Operation and Maintenance 5-12..............................................................
5.5.1 Software Loading 5-12......................................................................
5.5.2 Abis Interface Management 5-13......................................................
5.5.3 Air Interface Management 5-14........................................................
5.5.4 Testing Management 5-16................................................................
5.5.5 Status Management 5-16.................................................................
5.5.6 Processing of Event Reports 5-17....................................................
5.5.7 Equipment Management 5-18..........................................................
5.5.8 Site Configuration 5-20.....................................................................
5.5.9 Tracing Operations 5-20...................................................................5.5.10 Miscellaneous Functions 5-21........................................................
5.6 System Indices 5-21..................................................................................
5.7 Radio Interface Indices 5-23.....................................................................
5.7.1 Receiver Part 5-23............................................................................
5.7.2 Transmitter Part 5-26........................................................................
Chapter 6 Configuration and Typical Application 6-1.........................................
6.1 Configuration 6-1.....................................................................................
6.1.1 Cell Configuration 6-1.....................................................................
6.1.2 Configuration of the Common Resource Frame 6-2.......................6.1.3 Configuration of the TRX/CDU Frame 6-2......................................
6.1.4 Configuration of the Antenna 6-4....................................................
6.2 Typical Configuration 6-4........................................................................
6.2.1 S (4/4/4) Configuration 6-4.............................................................
6.2.2 S (2/2/2) Configuration 6-6.............................................................
6.2.3 O (6) Configuration 6-8...................................................................
6.2.4 O (4) Configuration 6-10...................................................................
Appendix A Abbreviations A-1............................................................................
Part 2 Maintenance Console Description
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Table of Contents i.........................................................................................
Chapter 1 Overview 1-1......................................................................................
1.1 Introduction to BTS Terminal Maintenance 1-1.......................................
1.2 Introduction to BTS Terminal Maintenance Operations 1-1....................
1.2.1 User Login 1-1................................................................................
1.2.2 Interface Operation 1-2...................................................................
Chapter 2 Site Maintenance 2-1.........................................................................
2.1 Overview 2-1...........................................................................................
2.2 Site Administrationship 2-1.....................................................................
2.3 OpStart Site 2-3......................................................................................
2.4 View Resource 2-4..................................................................................
2.5 Forced Load SW 2-4...............................................................................
2.6 SW Activate 2-6......................................................................................
2.7 Site Hierarchical Reset 2-7.....................................................................
2.8 Site Test 2-9............................................................................................
2.9 Site Environment Monitoring 2-9.............................................................
Chapter 3 Cell Maintenance 3-1.........................................................................
3.1 Overview 3-1...........................................................................................
3.2 Cell Attributes Management 3-2..............................................................
3.3 Cell Extended Attribute Management 3-4...............................................
3.4 OpStart Cell 3-6......................................................................................
3.5 Change Cell Administrative State 3-6.....................................................3.6 Cell Performance Test 3-7......................................................................
Chapter 4 BT Maintenance 4-1..........................................................................
4.1 Overview 4-1...........................................................................................
4.2 OpStart BT 4-2........................................................................................
4.3 Change BT Administrative State 4-2.......................................................
4.4 BT Reinitialization 4-3.............................................................................
4.5 BT Test 4-4.............................................................................................
Chapter 5 Channel Maintenance 5-1..................................................................
5.1 Overview 5-1...........................................................................................5.2 Channel Attributes Management 5-2......................................................
5.3 OpStart Channel 5-3...............................................................................
5.4 Change Channel Administrative State 5-3..............................................
5.5 Loop Test 5-4..........................................................................................
Chapter 6 RC Maintenance 6-1..........................................................................
6.1 Overview 6-1...........................................................................................
6.2 RC Attributes Management 6-2...............................................................
6.3 RC Extended Attributes Management 6-3..............................................
6.4 OpStart RC 6-4.......................................................................................
6.5 Change RC Administrative State 6-4......................................................
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6.6 RC Reinitialization 6-5.............................................................................
Chapter 7 Board Maintenance 7-1.....................................................................
7.1 Overview 7-1...........................................................................................
7.1.1 Board Maintenance 7-1..................................................................
7.1.2 Board Maintenance Operations 7-2................................................
7.2 Board Reset 7-4......................................................................................
7.3 OpStart Board 7-4...................................................................................
7.4 Board Self-test 7-5..................................................................................
7.5 Change Board Administrative State 7-5..................................................
7.6 Board Information 7-6.............................................................................
7.7 Loop Test 7-7..........................................................................................
7.8 Board Alarm 7-8......................................................................................
7.9 Clock Operation 7-9................................................................................
7.10 Set Antenna and Feeder Parameters 7-10.............................................
7.11 CDU Operation 7-11...............................................................................
Part 3 BTS Maintenance
Table of Contents i.........................................................................................
Chapter 1 Routine Maintenance Instructions 1-1...............................................
1.1 Routine Maintenance Overview 1-1........................................................
1.1.1 Purpose of Routine Maintenance 1-1.............................................
1.1.2 Routine Maintenance Classification 1-1.........................................
1.1.3 BTS Routine Maintenance Record & Instructions 1-2....................
1.2 Weekly Maintenance Instructions 1-8.....................................................
1.3 Monthly Maintenance Instructions 1-9....................................................
1.4 Quarterly Maintenance Instructions 1-10..................................................
1.5 Yearly Maintenance Instructions 1-11.......................................................
1.6 Return Loss, VSWR and Reflection Coefficient 1-12................................
Chapter 2 Fault Analysis and Location 2-1.........................................................
2.1 Communication Fault 2-1........................................................................
2.1.1 Introduction to MSs Search for the Network 2-1............................2.1.2 Call Failure 2-2...............................................................................
2.1.3 No Voice Heard after the Call is Connected 2-5.............................
2.1.4 Unidirectional Talk 2-6....................................................................
2.1.5 Poor Voice Quality 2-7....................................................................
2.1.6 Conversation Interruption 2-8.........................................................
2.1.7 Cross Talk 2-8................................................................................
2.1.8 Mobile Station Frequently Disconnected from the Network 2-9......
2.1.9 Immediate Assignment Rejection 2-10.............................................
2.2 Network Fault 2-10....................................................................................2.2.1 Mobile Station Fails to Find a Network 2-10.....................................
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2.2.2 Mobile Station Fails to Access the Network 2-12.............................
2.2.3 MS Frequent Location Updating 2-14...............................................
2.3 Loading Fault 2-15....................................................................................
2.3.1 Software Loading Failure 2-15..........................................................
2.3.2 Base Station Initialization Failure 2-17.............................................
2.4 Signaling Fault 2-19..................................................................................
2.4.1 OML Link Blocked 2-19....................................................................
2.4.2 RSL Link Blocked 2-19.....................................................................
2.5 Antenna and Feeder System Fault 2-20...................................................
2.5.1 Fault Description 2-20.......................................................................
2.5.2 Introduction to the Antenna and Feeder System 2-21......................
2.5.3 Fault Analysis and Location 2-21......................................................
2.5.4 Troubleshooting Procedure 2-21......................................................
2.6 Optical Channel Fault 2-22.......................................................................
2.6.1 Fault Description 2-22.......................................................................
2.6.2 Fault Analysis and Location 2-22......................................................
2.6.3 Troubleshooting Procedure 2-22......................................................
2.7 Board Fault 2-23.......................................................................................
2.7.1 TMU 2-23..........................................................................................
2.7.2 CDU 2-25..........................................................................................
2.7.3 EDU 2-29..........................................................................................
2.7.4 SCU 2-32..........................................................................................2.7.5 TRX 2-34..........................................................................................
2.7.6 PBU 2-36..........................................................................................
2.7.7 PMU 2-38..........................................................................................
2.7.8 PSU 2-42..........................................................................................
2.7.9 TEU 2-43..........................................................................................
2.7.10 TES 2-45.........................................................................................
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HUAWEI
1. System Description
2. Maintenance Console Description
3. BTS Maintenance
M900/M1800 Base Transceiver Station (BTS312)
User Manual
V300R002
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M900/M1800 Base Transceiver Station (BTS312)
User Manual
Manual Version T2-030129-20040310-C-4.03
Product Version V300R002
BOM 31013229
Huawei Technologies Co., Ltd. provides customers with comprehensive technical support
and service. Please feel free to contact our local office or company headquarters.
Huawei Technologies Co., Ltd.
Address: Administration Building, Huawei Technologies Co., Ltd.,
Bantian, Longgang District, Shenzhen, P. R. China
Postal Code: 518129
Website: http://www.huawei.com
Email: support@huawei.com
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Copyright 2004 Huawei Technologies Co., Ltd.
All Rights Reserved
No part of this manual may be reproduced or transmitted in any form or by any
means without prior written consent of Huawei Technologies Co., Ltd.
Trademarks
, HUAWEI, C&C08, EAST8000, HONET, , ViewPoint, INtess, ETS, DMC,
TELLIN, InfoLink, Netkey, Quidway, SYNLOCK, Radium, M900/M1800,
TELESIGHT, Quidview, Musa, Airbridge, Tellwin, Inmedia, VRP, DOPRA, iTELLIN,
HUAWEI OptiX, C&C08iNET, NETENGINE, OptiX, iSite, U-SYS, iMUSE, OpenEye,
Lansway, SmartAX, infoX, TopEng are trademarks of Huawei Technologies Co.,
Ltd.
All other trademarks mentioned in this manual are the property of their respective
holders.
Notice
The information in this manual is subject to change without notice. Every effort has
been made in the preparation of this manual to ensure accuracy of the contents, but
all statements, information, and recommendations in this manual do not constitute
the warranty of any kind, express or implied.
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About This Manual
Release Notes
The product version that corresponds to the manual is M900/M1800 Base Transceiver
Station (BTS312) V300R002.
Related Manuals
The following manuals provide more information about the M900/M1800 Base
Transceiver Station (BTS312).
Manual Content
M900/M1800 Base TransceiverStation (BTS312) User Manual
It provides an overall introduction to the BTS312, includingthe software structure, hardware structure, applications,technical specifications and maintenance method.
M900/M1800 Base Transceiver Station(BTS312) Installation Manual
It provides information for the system installation, includingthe hardware installation and software installation.
Organization of the Manual
M900/M1800 Base Transceiver Station (BTS312) User Manual describes such
contents of the BTS312as the product features, architecture, and working principle of
each functional part. It includes 3 volumes and their contents are listed as follows:
System Description gives a general description of the BTS312, including the key
features, technical indices, functions, and operation and maintenance structure, and
users can get the basic information of BTS312.
Maintenance Console Description is used to guide users how to operate the local
maintenance console. It describes every operation by means of interface, and helps
users to get familiar with the routine operation of the BTS312, and learn about its
running status.
BTS Maintenance introduced the routine maintenance instructions, faulty analysis and
location of BTS312.
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HUAWEI
M900/M1800 Base Transceiver Station (BTS312)User Manual
Part 1 System Description
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User ManualM900/M1800 Base Transceiver Station (BTS312)
System DescriptionTable of Contents
i
Table of Contents
Chapter 1 An Introduction to BTS312 ......................................................................................... 1-11.1 System Overview............................................................................................................... 1-11.2 System Characteristics...................................................................................................... 1-2
1.2.1 Integrated RF Component Technology................................................................... 1-21.2.2 Mature RF Technology............................................................................................ 1-21.2.3 Advanced E-Abis Technology................................................................................. 1-21.2.4 Powerful O&M Functions ........................................................................................ 1-3
1.3 Application Merits............................................................................................................... 1-31.3.1 Wide Coverage........................................................................................................ 1-31.3.2 Expenditure Reduction............................................................................................ 1-41.3.3 Smooth Evolution.................................................................................................... 1-41.3.4 Multiple Transmission Modes.................................................................................. 1-4
1.4 Structure Overview ............................................................................................................ 1-41.4.1 Logical Structure ..................................................................................................... 1-41.4.2 Software Structure .................................................................................................. 1-61.4.3 Cabinet Structure .................................................................................................... 1-7
1.5 Main Functions................................................................................................................... 1-81.5.1 Basic Software Relative Functions.......................................................................... 1-81.5.2 Basic Hardware Relative Functions ........................................................................ 1-9
1.6 Technical Indices ............................................................................................................... 1-9Chapter 2 Hardware Architecture ................................................................................................2-1
2.1 Overview............................................................................................................................ 2-12.2 TRX/CDU Frame................................................................................................................ 2-3
2.2.1 CDU......................................................................................................................... 2-32.2.2 EDU......................................................................................................................... 2-42.2.3 ECDU ...................................................................................................................... 2-52.2.4 SCU......................................................................................................................... 2-62.2.5 TRX ......................................................................................................................... 2-62.2.6 PBU....................................................................................................................... 2-10
2.3 Common Resource Frame .............................................................................................. 2-122.3.1 PSU....................................................................................................................... 2-122.3.2 PMU ......................................................................................................................2-122.3.3 TMU....................................................................................................................... 2-142.3.4 TES ....................................................................................................................... 2-172.3.5 ASU....................................................................................................................... 2-182.3.6 ABB ....................................................................................................................... 2-202.3.7 ABA ....................................................................................................................... 2-21
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User ManualM900/M1800 Base Transceiver Station (BTS312)
System DescriptionTable of Contents
ii
2.4 Other Parts of the Cabinet ............................................................................................... 2-212.4.1 TDU....................................................................................................................... 2-212.4.2 FMU....................................................................................................................... 2-232.4.3 Switch Box............................................................................................................. 2-24
2.4.4 Fan Box................................................................................................................. 2-242.4.5 Air Box................................................................................................................... 2-25
2.5 Antenna and Feeder System........................................................................................... 2-252.5.1 Antenna................................................................................................................. 2-252.5.2 Feeder................................................................................................................... 2-272.5.3 Lightning Arrester.................................................................................................. 2-272.5.4 Tower-top Amplifier (Optional) .............................................................................. 2-27
2.6 Power Supply System...................................................................................................... 2-282.6.1 Overview ............................................................................................................... 2-282.6.2 Overall Structure ................................................................................................... 2-302.6.3 Technical Specifications........................................................................................ 2-32
2.7 Environment Monitoring System...................................................................................... 2-362.7.1 Outlook of Environment Monitoring instrument..................................................... 2-362.7.2 Function Provided by Environment Monitoring Instrument ................................... 2-372.7.3 Environment Monitoring Instrument Inputs ........................................................... 2-372.7.4 Alarm Indicators .................................................................................................... 2-382.7.5 Executing Devices................................................................................................. 2-382.7.6 Communication ..................................................................................................... 2-39
2.8 Lightning Protection System............................................................................................ 2-392.8.1 Lightning Protection for DC Power Supply............................................................ 2-402.8.2 Lightning Protection for AC Power Supply............................................................ 2-422.8.3 Lightning Protection for Trunk Cables................................................................... 2-43
Chapter 3 Software Architecture ................................................................................................. 3-13.1 Overview............................................................................................................................ 3-13.2 Signaling Control Processing (SCP) Program................................................................... 3-23.3 Baseband Signal Processing Program.............................................................................. 3-43.4 Operation and Maintenance Program ............................................................................... 3-5
Chapter 4 External Interfaces....................................................................................................... 4-1
4.1 Abis Interface..................................................................................................................... 4-14.1.1 Introduction.............................................................................................................. 4-14.1.2 Physical Layer......................................................................................................... 4-64.1.3 Data Link Layer ....................................................................................................... 4-74.1.4 Layer 3 - Traffic Management................................................................................. 4-84.1.5 Layer 3 - Operation and Maintenance .................................................................. 4-12
4.2 Um Interface .................................................................................................................... 4-144.2.1 Introduction............................................................................................................ 4-144.2.2 Interface Protocol Model ....................................................................................... 4-154.2.3 Physical Layer....................................................................................................... 4-15
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User ManualM900/M1800 Base Transceiver Station (BTS312)
System DescriptionTable of Contents
iii
4.2.4 Data Link Layer ..................................................................................................... 4-204.2.5 Signaling Layer...................................................................................................... 4-23
Chapter 5 Functions and Performance....................................................................................... 5-15.1 Networking Functions ........................................................................................................ 5-1
5.1.1 E1 Networking......................................................................................................... 5-15.1.2 SDH Networking...................................................................................................... 5-35.1.3 Networking for Satellite Transmission..................................................................... 5-4
5.2 Main RF Functions............................................................................................................. 5-65.3 Baseband Processing........................................................................................................ 5-8
5.3.1 Channel Types Supported ...................................................................................... 5-85.3.2 Channel Combinations Supported .......................................................................... 5-9
5.4 Signaling Processing ......................................................................................................... 5-95.5 Operation and Maintenance ............................................................................................ 5-12
5.5.1 Software Loading .................................................................................................. 5-125.5.2 Abis Interface Management .................................................................................. 5-135.5.3 Air Interface Management..................................................................................... 5-145.5.4 Testing Management ............................................................................................ 5-165.5.5 Status Management.............................................................................................. 5-165.5.6 Processing of Event Reports................................................................................. 5-175.5.7 Equipment Management ....................................................................................... 5-185.5.8 Site Configuration.................................................................................................. 5-205.5.9 Tracing Operations................................................................................................5-205.5.10 Miscellaneous Functions..................................................................................... 5-21
5.6 System Indices................................................................................................................. 5-215.7 Radio Interface Indices.................................................................................................... 5-23
5.7.1 Receiver Part......................................................................................................... 5-235.7.2 Transmitter Part..................................................................................................... 5-26
Chapter 6 Configuration and Typical Application...................................................................... 6-16.1 Configuration...................................................................................................................... 6-1
6.1.1 Cell Configuration.................................................................................................... 6-16.1.2 Configuration of the Common Resource Frame ..................................................... 6-26.1.3 Configuration of the TRX/CDU Frame .................................................................... 6-2
6.1.4 Configuration of the Antenna .................................................................................. 6-4
6.2 Typical Configuration......................................................................................................... 6-46.2.1 S (4/4/4) Configuration............................................................................................ 6-46.2.2 S (2/2/2) Configuration............................................................................................ 6-66.2.3 O (6) Configuration.................................................................................................. 6-86.2.4 O (4) Configuration................................................................................................ 6-10
Appendix A Abbreviations ...........................................................................................................A-1
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User ManualM900/M1800 Base Transceiver Station (BTS312)
System DescriptionChapter 1 An Introduction to BTS312
1-1
Chapter 1 An Introduction to BTS3121.1 System Overview
In a GSM network, a Base Transceiver Station (BTS) belongs to the radio part of the
base station subsystem, i.e. transmitting functions are performed by BTS. Figure 1-1
shows that a BTS is a set of transceiver equipment that serves a certain cell and is
controlled by the BSC (Base Station Controller).
MSC: Mobile Switching Center BSC: Base Station Controller SMC: Short Message Center
HLR: Home Location Register BTS: Base Transceiver Station VM: Voice Mailbox
AUC: AUthentication Center MS: Mobile Station OMC: Operation/Maintenance Center
VLR: Visitor Location Register EIR: Equipment Identify Register
Other MSC/VLR
MAP
M900 BTS
M900 BTS SMC&VMOMC
M900/M1800 BSC
TUP , ISUP
MAP
A interface
MSHLR/AUC/EIR
M900/M1800 MSC/VLR
M1800 BTSM900 BTS
PSTN
ISDNPSPDN
Um interface
MS
LAN/WAN
Figure 1-1Position of the BTSs in the GSM system
A BTS connects with the BSC via the Abis interface. The air interface (Um interface),
is used to realize the radio transmission between the BTS and the MS as well as the
associated control functions.
The BTS processes messages on layer 1, layer 2, and non-transparent transmission
layer 3 on radio links and performs the related control functions, including:
z Interfacing with the BSC
z Radio channel management
z Operation and maintenance functions
z Signaling protocol functions
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User ManualM900/M1800 Base Transceiver Station (BTS312)
System DescriptionChapter 1 An Introduction to BTS312
1-2
1.2 System Characteristics
The M900/M1800 BTS312 is designed as a typical all-in-one BTS by taking full
consideration of the requirements of capacity, configuration, installation, power supply,
transmission, and services. Its characteristics are as follows.
1.2.1 Integrated RF Component Technology
z Expansion based on the inheritance of the investment: BTS expansion can make
the utmost of all the antenna and feeder parts.
z Modular structure with good performance: RF combiner, divider and low noise
amplifier are integrated in CDU (Combining and Distribution Unit). All parts for
TRX processing including baseband processing, RF processing, poweramplification and power supply are all integrated in one TRX (Transceiver unit).
Modular structure can reduce internal cable connections, improve system
reliability and facilitate installation and maintenance.
z Intelligent CDU: Fine monitor and control function, excellent O&M, level 2
standing wave ratio alarm, low noise amplifier alarm, TTA (Tower Top Amplifier)
alarm, TTA power supply. Auto protection against emergency: Close
transmission power when transmit path antenna feeder is abnormal; power off to
bypass LNA (Low Noise Amplifier) when TTA is abnormal so as to ensure
normal system operation. Receive gain can be adjusted via remote control to
ensure the sensitivity of the receive system.
1.2.2 Mature RF Technology
z RF hopping and baseband frequency hopping are provided to improve system
anti-interference capability. It has good performance in practical application.
z Advanced digital RF technology is adopted to raise batch consistency,
manufacture scalability and stability of the RF system.
1.2.3 Advanced E-Abis Technology
The E-Abis (Enhanced Abis) supports various transmission modes and complex
topologies, e.g. SDH, E1, microwave, satellite, etc.
The E-Abis includes the following techniques:
z APL (Advanced Phase Locking) technique solves the problem of clock jittery, by
using high-precision clock and characteristic software phase lock technique. The
problems such as SDH clock phase jittery, signal out of lock during transmission
via satellite are solved.
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User ManualM900/M1800 Base Transceiver Station (BTS312)
System DescriptionChapter 1 An Introduction to BTS312
1-4
1.3.2 Expenditure Reduction
z It supports multiplexing of 15:1, hence greatly reducing transmission
expenditure.
z Transmission equipment such as SDH is integrated, providing a solution for
future upgrade and wideband radio access and reducing transmission equipment
investment.
z High reliability: Centralized power supply while providing power to various
modules in a distributed way. BTS312 can provide DC +24V, DC -48V and AC
220V to satisfy different power supply requirement.
1.3.3 Smooth Evolution
z Mixed dual band plug-in of 900MHz and 1800MHz modules of 6 cells.
z GPRS (General Packet Radio Service), which helps to realize smooth evolution
from 2G to 2.5G.
1.3.4 Multiple Transmission Modes
z Multiple built-in transmission modes: 75 /E1, 120/E1 and SDH. The BTS has
powerful transmission adaptability.
1.4 Structure Overview
1.4.1 Logical Structure
In the GSM system, the BTS functions as a radio relay, connected with the MS via the
Um interface on one side and to the BSC via the Abis interface on the other side.
The logical structure of the BTS is shown in Figure 1-2.
TRX
TRX
TRX
CDU
CDU
CDU
FHBUS
TTA TTA
TTA TTA
TTA TTA
PMUPSU
FMU
TDU
TMU
TEU TES
Abis
E1
Fiber(Optinal)
Common Unit Signaling Processor Unit Antenna Feeder Unit
External Alarm
Um
CBUS/TBUS/DBUS
BSC
ABB&ABA
Figure 1-2BTS312 logical structure
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As shown in Figure 1-2, the hardware of BTS312 includes the following three
functional parts: common unit, carrier unit and antenna unit.
I. Common Unit
The common unit consists of the Timing/transmission and Management Unit (TMU),
the Timing Distribution Unit (TDU), the Transmission Extension Unit (TEU), the
Transmission Extension power Supply unit (TES), the Fan Monitor Unit (FMU), the
Power Supply Unit (PSU), the Power Monitoring Unit (PMU), the switch box, the fan
box and the air box.
z TMU is the basic transmission and control function entity in a BTS
z TDU is installed on the top of the cabinet.
z TEU is an optional unit used for SDH transmission.
z TES is the power supply unit of TEU.z FMU within the fan box controls the normal operation of fans and reports alarms
in case of fan failure.
z PSU is the power supply unit for the whole system.
z PMU is the power monitoring unit.
z ABB is the Abis bypass board for the BTS312 in the chain networking.
z ABA is the Abis bypass assistant board.
z Switch box: distributed power supply is adopted to improve the reliability of
power supply.
z Fan box: FMU is installed within the fan box.
z Air box is the inlet for the cool air. It is part of the cooling system to guarantee
the normal operation of BTS.
II. Carrier unit
The carrier unit comprises Transceiver (TRX) unit, Power Booster Unit (PBU),
Combiner and Divider Unit (CDU), Enhanced Duplexer Unit (EDU) and Simple
Combiner Unit (SCU).
z TRX is a software and hardware entity that performs all processing functions of
one carrier.
z PBU is the output power booster of TRX. It also provides the function of alarm
collection.
z CDU supports broadband hybrid combining. At the transmitting end, signals of 2
channels are combined into 1 (2-into-1), while at the receiving end signals from 2
channels are divided into 4 (or 8 in case of only one channel) channels.
z EDU is a low-loss duplex divider unit which can achieve the transmitting and
diversity receiving of signals for two TRXs.
z SCU fulfills 4-into-1 combining. It is used to save CDUs.
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III. Antenna unit
Antenna unit implements the receiving and transmitting of RF signals. It includes the
antenna, feeder, low-loss transmission cable and lightning arrester.
1.4.2 Software Structure
BTS software not only performs the protocol functions specified in the signaling model
shown in Figure 1-3, but also implements BTS operation, maintenance and testing
functions.
Based on different hardware entities, BTS software consists of:
z Radio interface signal processing unit, i.e., the Um interface media access layer
running in the digital signal processing unit of the TRX module,z Signaling processing unit, including radio resources management (RR), Abis
interface link layer protocol (LAPD), Abis interface media access control layer,
Um interface link layer protocol (LAPDm), etc. which run in the signaling
processing unit of TRX module,
z Operation and maintenance unit, including BTS fault management, performance
management, configuration management, security management, data
management, Abis interface transmission control and local man-machine
interface, which run in the TMU unit.
z BTS software also includes the programs handling the communication among
various units in BTS.
MM
RR
LAPDm
Sign.
Layer 1
L3
L2
L1
LAPDm
Sign.
Layer 1
Sign.
LAPD
Layer 1
MS
Um
LAPD
Sign.
Layer 1
SCCP
MTP
BTSM
RR BSSAP
Abis
BTS BSC
RR
CM
BTSM
CM: Connection Management LAPD: Link Access Protocol on D channelMM: Mobility Management LAPDm: Link Access Protocol on Dm channelRR: Radio Resource Management SCCP: Signaling Connection Control PartBTSM: BTS Management MTP: Message Transfer PartBSSAP: Base Station Subsystem Application Part
Figure 1-3BTS signaling structure
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1.4.3 Cabinet Structure
I. Dimensions
The cabinet of the BTS312 is designed in accordance with the IEC297 standard, with
the following dimensions:
HeightWidthDepth=1880mm650mm500mm.
The cabinet is shown in Figure 1-4.
(1) TRX/CDUframe
(2) Rack (3) Common resource frame (4) Switch box (5) Small fan box
(6) Air box (7) Large fan box (8) Front door (9) Back plate
Figure 1-4General view of the cabinet
II. Cabinet features
z Standard cabinet.
z Strong and simple structure.
z
Aluminum alloys are used to reduce the cabinet's weight.
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z Good shielding effect and conductivity.
z Wind tunnels ensure good ventilation and heat dissipation.
z Simple and convenient installation and maintenance.
1.5 Main Functions
Basic functions provided by BTS312 software and hardware are listed below.
1.5.1 Basic Software Relative Functions
The BTS312 has the following main functions:
z Support both 900MHz and 1800MHz frequency systems.
z Support EGSM/RGSM extended frequency band services.
z All data services prescribed in Phase II+.
z Support GPRS.
z Support Phase I/Phase II /Phase II+ compatible LAPDm protocol.
z Support Phase I/Phase II/Phase II+ compatible system message issuing and
resources instruction.
z Support CS-1/CS-2/CS-3/CS-4 radio channel coding scheme.
z Support FR (Full Rate) / EFR (Enhanced Full Rate) / HR (Half Rate) and all
kinds of speech coding scheme.
z Support broadcast short message and point-to-point short message.
z Support paging queue.z Support A5/1, A5/2 encryption/decryption.
z Support basic data dynamic configuration.
z Support basic data dynamic configuration.
z Support measurement report preprocessing.
z Support Abis,10:1, 12:1 and 15:1signaling multiplexing.
z Support BCCH carrier cooperation.
z Support immediate assignment combination and paging combination, boosting
the radio channel efficiency.
z Support discontinuous transmission (DTX) enhancing the anti-interference ability
and reducing the power consumption. Support DRX.
z Support omni cell and directional cell.
z Support chain/tree/start/loop networking.
z Support locked, fast pull-in, holdover and free run clock modes.
z Support synchronous, asynchronous and quasi-synchronous handover.
z Support Um interface tracing and internal interface tracing.
z Support remote and local loading of software.
z Support dynamic and static power control.
z Support satellite transmission and Abis 16k signaling transmission.
z Support extended cell.
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Weight bearing requirement: 400kg/m2
(with 10% tolerance)
z Power consumption
Maximum power consumption of a single cabinet: 2400W
z Receiving sensitivity
-110dBm (GSM900), -109dBm (GSM1800)
z Transmitting power
TRX output power: 40W (46dBm) or 60W (47.8dBm)
TRX+PBU output power: 80W (49dBm)
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Chapter 2 Hardware Architecture
2.1 Overview
A BTS312 cabinet mainly comprises a common resource frame and a TRX/CDU
frame, which can be flexibly configured according to the user demands. There are
also some other elements like TDU, switch box, fan box, air box, etc.
The hardware architecture of the BTS312 cabinet is shown in Figure 2-1.
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TX
RX
TRX
TX
RX
TRX
TX
RX
TRX
TX
RX
TRXCDU
TX
RX
TRX
TX
RX
TRX
TX
RX
TRX
TX
RX
TRXCDUCDU
TX
RX
TRX
TX
RX
TRX
TX
RX
TRX
TX
RX
TRXCDUCDU
AIR BOX
FAN BOXFAN BOX
P
M
P
S
U
P
S
U
P
S
U
P
S
U
P
S
U
P
S
U U
T
M
U
T
M
U
T
U
E
T
U
E
T
E
S
AIR BOX
SWITCH BOX
FAN BOX
TDU
CDU
CDU: Combiner and Divider Unit TRX: TransceiverPMU: Power supply Management Unit TMU: Timing/Transmission Management UnitPSU: Power Supply Unit TES: Transmission Extension power SupplyTEU: Transmission Extension Unit TDU: Timing Distribution Unit
Figure 2-1Hardware architecture of the BTS312 cabinet
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EDU
Test coupler Amp. feeder
Divider
Duplexer
LNA
Alarm and control unit
Tx signal input
Rx signal output
Divider
Rx signal output
LNA
Amp. feederTx signal input Duplexer Test coupler
Figure 2-3Functional blocks of the EDU
Besides the combining and dividing functions, the EDU also provides the following
alarm detection functions:
z VSWR (Voltage Standing Wave Ratio) monitoring: Monitoring the status of the
antenna system. When the VSWR exceeds the threshold 2.5:1, the EDU reports
alarm.
z Low noise amplifier fault alarm: The status of the LNA can be determined based
on the power supply current. When the current exceeds a certain level, alarm
signals and indications are generated.
z
Tower-top amplifier alarm: When there is tower-top amplifier in service, EDUdetermines the operation status of the amplifier according to the working current
of amplifier. If the current exceeds preset value or there is no current, alarm
signal will be generated.
z Control functions: Remotely control the low noise amplifier attenuation (dynamic
control 15 levels, in steps of 1dB) both in the main receiving path and diversity
receiving path, supply/cut feeder depends on whether tower-top amplifier is
equipped, cut the feeder to the amplifier in case of alarm.
2.2.3 ECDU
The functions and external interfaces (including dimensions) of ECDU are the same
as that of CDU. It implements combination of transmitted signals, dividing of received
signals, and duplex functions. The difference is that the maximum power input of
ECDU reaches 100W.
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2.2.4 SCU
I. General
SCU combines the signals from 4 TRXs into 1 channel for transmission. It employs
the electric bridge with 3dB power loss to achieve the broadband combing. Used
together with CDU, it can achieve the combination of signals from multiple TRXs. The
introduction of SCU is to reduce the number of CDUs, hence saving costs.
II. Structure and function
The functional blocks of the SCU are shown in Figure 2-4.
SCU
1
2
3
4
CombinerTx signal input
Combiner
Tx signal outputCombiner
Figure 2-4Functional blocks of the SCU
2.2.5 TRX
I. General
TRX is the key part of the BTS which receives various types of management and
configuration information issued by the TMU and reports its status and alarm
information to the TMU.
The TRX separates the received information from the mobile stations through
demodulation and balancing into signaling and speech information, and transmits
them upward (i.e. to BSC and MSC). The downlink signaling and speech information
is sent to the CDU and the antenna after being processed by the TRX.
With a modular structure, the TRX module contains both the baseband processing
unit, and the radio frequency unit.
II. Structure and functions
The structure of the TRX unit is shown in Figure 2-5. It includes the baseband signal
processing unit (TBU) and the radio frequency signal processing unit (RPU).
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SCP DSP CUITDP PAU
RCU
TBU RPU
DBUS FH _BUS
CBUS
TIMING_BUS
Clock processing part
Send
Main receiverDiversity receiver
SCP: Signaling Processing Unit DSP: Digital Signal Processing Unit CUI: Carrier Unit InterfacePAU: Power Amplifier Unit RCU: Receiving Unit TDP: Transmitter Driver and PLL unitRPU: RF signal Processing Unit TBPU: TRX Baseband signal Processing UnitCBUS: Control Bus FH_BUS: Frequency Hopping Bus DBUS: Data Bus
Figure 2-5Structure of the TRX unit
1) Baseband signal processing unit (TBU)
The TBU consists mainly of the Signaling Processing Unit (SCP), the Digital Signal
Processing unit (DSP), and the Carrier Unit Interface (CUI). As the GSM system is a
time division multiplexing system, the operation of the TRX relies on various clocks.
So the TRX contains some clock processing logical units.
z Signaling processing unit (SCP)
The SCP processes signaling protocols on different BTS interfaces, including the
layer 2 protocol LAPDm with the mobile station (MS), the layer 2 protocol LAPD with
the BSC interface, and the layer 2 protocol (DCL) with the operation & maintenance
module (OMU), as well as layer 3 non-transparent messages.
The SCP also handles DSP program loading and alarm processing of the whole TRX
module.
z Digital signal processing unit (DSP)
The DSP performs such functions as signal encoding/decoding, signal demodulation,
interleaving and de-interleaving, and speech/data communication with the TRAU.
It sends the signaling received from the MS to the SCP, receives signaling sent from
the SCP, and performs corresponding encoding/decoding according to related
protocols. It sends the downlink data via the CUI to the carrier unit RPU.
z Carrier unit interface (CUI)
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The CUI is the interface between the DSP and the RPU. It supports baseband
hopping, and according to system configuration can work in either hopping or
non-hopping mode (when the system works in the RF hopping mode, the hopping
interface works in non-hopping mode and the hopping functions are completed by thecarrier unit).
The CUI samples and filters the uplink intermediate frequency signals sent from the
RPU, and sends them to the DSP for demodulation and combination.
z Clock processing part
The TRX extracts clocks sent from the TMU over the clock buses. To ensure the
reliability, the clock buses work in active/standby mode. These clocks include the
frame clock, the octet bit clock, and the frame number.
The clock processing part in the TRX first chooses either the active clock or thestandby clock, then makes frequency division calculation and generates the timeslot
number and bit clocks required by the local TRX.
2) Radio frequency signal processing unit (RPU)
The RPU consists of 3 parts: Receiving Unit (RCU), Transmitter Driver and PLL unit
(TDP), and Power Amplification Unit (PAU).
z Receiving unit (RCU)
The RCU provides diversity reception functions, that is, the receiver consists of two
completely independent channels, and the input signals come from the main antenna
and diversity antenna. In complicated radio transmission areas where one antenna
receives very poor signal, the signal received from the other (diversity) antenna may
be of a better quality.
The BTS receives signals from both the main channel and the diversity channel, then
handles demodulation after combination algorithms. It can provide 3~5dB diversity
gain, thus improving the communication quality.
Each receiving channel consists of down conversion circuits. The received signals are
sent to the frequency mixer after filtering and amplification, so as to generate
intermediate frequency signals, which after further filtering and amplification aredirectly sent to the baseband unit for digital demodulation processing.
z Transmitter Driver and PLL unit (TDP)
This unit consists of 3 parts, transmitter excitation, frequency synthesizer, and PLL
testing.
Transmitter excitation unit directly modulates the I and Q signals sent from the
baseband unit through the orthogonal modulator into the radio signals for
transmission. This works rather simple and reliable.
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After modulation, the signal controlled by the APC provides the power amplifier unit
(PAU) with a certain power level.
The transmitter excitation unit also provides the dynamic and static power control at
the base station. Static power control (the maximum transmission power of the base
station) is specified during network planning. In contrast, dynamic power control is
performed during communication. Static power control has 0~10 levels (level 0 is
46dBm), decrementing by 2dBm each level. Dynamic power control has 0~15 levels,
decrementing by 2dBm each level.
To reduce noise in the radio environment and improves the network capacity and
service quality, the base station transmission power should be kept as low as possible
as long as the communication quality can be ensured. So each traffic channel is kept
at the lowest possible dynamic power level, with all idle channels transmission shut
down.
Moreover, transmitter excitation also provides the over-power alarm signal and
under-power alarm signal of the TRX. When the TRX output power is 3dB higher than
the specified level, over-power alarm will be generated. When the TRX output power
is 3dB lower than the specified level, under-power alarm will be generated.
Frequency synthesizer is the essential part of the whole transceiver. It generates
various local oscillation for the up/down frequency conversions, such as transmitter
local oscillation, receiver local oscillation, and PLL test local oscillation. Each of the
transmitter local oscillation and receiver local oscillation has two loops to achievehopping loop switchover.PLL testing is designed for TRX loopback testing. It attenuates part of the signals
coupled by the power amplifier output into the receiving frequency band through
frequency conversion, then sends them to the receiver after coupling. It is used to
check the TRX transmit channel and the receive channel.
z Power amplifier unit (PAU)
The PAU mainly performs radio signal amplification. Its maximum output power level
can be 46dBm or 47.8dBm. It also provides feed sampling signals controlled by the
transmitter APC, and the following alarm information:
z Over-temperature alarm, when the temperature of the power amplifier exceeds
85C, the power amplifier unit reports the high-temperature alarm via the
baseband unit, and automatically turns off the power amplifier.
z Over standing wave alarm, when the standing wave at the power amplifier output
end exceeds 3.5, it reports standing wave alarm to the baseband unit.
III. Interface
External interfaces of the TRX module includes:
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Input coupling & delay filtering
Amp. & phase control 60W power amplify
Power Synthesizer Module
Alarm collect & outputControl signal generation
Alarm Management Module
26V
26V
8V
8V
Alarm collectionPower amplify control
Alarm output
26V
TRXpoweroutput
PBU
CoupleOutput
PBU
poweroutput
Powermodule
Power
synthesize
andde
tect
Figure 2-6Functional blocks of PBU
The PBU couples the 40W power signals output from the TRX into main channel
signals and coupled channel signals. The main channel signals, after delay filtering,
enter the power synthesizer unit. The coupled channel signals are amplified into 60W
signals before being sent to the power synthesizer unit. To obtain final combined
signals, amplitude and phase control will be conducted on the 2 channels of input
signals.
The generation of control signals and the collecting/reporting of alarms are completedby the alarm management module. While the coupling, controlling and synthesizing of
power signals are performed by the power synthesizer module.
1) Power synthesizer module
Under the control of alarm management module, the power synthesizer module
amplifies TRX output signals, and at the same time provides power control and alarm
information, and alarm signals to the alarm management module, which detects
power amplification functionality and reports alarms.
2) Alarm management module
The alarm management module receives from the power synthesizer module the
power control and alarm information, and alarm signals. It is responsible for the
detection of power amplification functionality and the control over amplitude and
phase. It also reports the relevant alarms.
3) Power supply module
The power supply module supplies power to the power synthesizer module and the
alarm management module.
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2.3 Common Resource Frame
The common resource frame is the most import part of the cabinet. It includes 14
slots. Except for slots No.8 and No.9 which are reserved, other slots are respectivelyconfigured (from left to right) with PSUs (6 slots), PMU, TMU, TES and TEU.
Configurations of the TES and the TEU are optional.
2.3.1 PSU
PSU is a built in power supply module.
Depending on the power supply mode, BTS312 uses the power supply module of
different models. When 220V AC is adopted, the BTS uses the power supply module
with 220V AC input and +26V DC output. When +48V DC is adopted, it uses themodule with +48V DC input and +26V DC output. When +24V DC is used, no power
supply module is needed.
One PCU can supply power to two TRXs in N+1 flow-equalization hot-standby mode.
The working current of the module is 25A.
Note:For detailed descriptions, please refer to section 2.6, "Power Supply System".
2.3.2 PMU
I. General
PMU (Power Monitoring Unit) is close to the power supply module, managing the
power supply of the module. There are two types of PMUs: PMU for the DC/DC
module and PMU for the AC/DC module. The main difference between these two is
the battery management function. To reduce work load, both the AC/DC module and
the DC/DC module share one monitoring board.
II. Functions
Following describes the AC/DC module monitoring board.
1) Control
z Switch on/off of the power module (remote control available), with an output
signal of 12V/10mA
z Floating/equalizing charge of battery and current limit control
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z Connect/disconnect control of battery protection load, with a 230.5V output
low-voltage alarm, loading power-on/off condition
2) Switch signals
z
AC mains on/off signal and high-/low-voltage signal (12V/10mA)z Four fault status parameters (12V/10mA) provided to the monitoring board by 4
AC/DC modules
z Fan monitoring status parameters (normally, 12V/10mA)
z Fuse on/off status parameters of external battery (-0.3V
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2.3.3 TMU
I. General
TMU is located in the common frame of M900/M1800 BTS312. It is the timing,
transmission and management function entity of BTS312. It has the following main
functions:
z Provides channel multiplexing and flexible networking modes (including star-,
tree-, and chain- connections).
z Provides Man-Machine Interfaces (MMI) and operation & maintenance links for
software loading, fault management, configuration management, performance
management and security management, etc.
z Provides centralized BTS clock and its management, and clock hot standby
function.
z Provides alarm signal input ports, and handles external alarm collection and
control.
Two TMUs can be configured in the basic cabinet, providing clock source in hot
standby mode and serving to increase the number of E1 interfaces (each TMU
provides 4 E1 interfaces). In combined cabinet configurations, TMU boards are
configured in the basic cabinet only.
II. Structure and working principle
The functional blocks of the TMU are shown in Figure 2-8.
MCK
OMU
BIU
EAC
DBUS
CBUSMMI
BSC
MCK
Active TMU
Environment Monitors
Abis
TDU
Standby TMU
BIU
TBUS
Maintenance Terminal
RS485
External clock
BSC: Base Station Control TMU: Timing/Transmission and Management UnitBIU: Base Station Interface Unit OMU: Operation and Maintenance Unit TDU: Timing Distribution UnitEAC: External Alarm Collector MCK: Main Clock module DBUS: Data BusCBUS: Control Bus TBUS: Timing Bus
Figure 2-8Functional blocks of the TMU
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1) Base station interface unit (BIU)
The BIU handles conversion and reconversion between digital signals of the BTS
internal HWs and the HDB3 codes (on E1 lines). It switches timeslots on HW to
achieve flexible timeslot configuration, extracts superior clock signals, supportsexternal clock input, and outputs accurate clock signals through phase locking and
frequency division. It synchronizes internal bus data transmission, or generates
free-run clock signals when superior clocks are not available (due to E1 line or BSC
fault) to synchronize internal bus data transmission, and generates alarm and reports
them to OMU.
One BIU module can support a maximum of 4 E1 lines. The BIU modules on the two
TMU boards in one cabinet can be mutually extended, and the data on the 8 mutually
extended E1 lines can be freely switched. The E1 interfaces on the BIU module can
be respectively connected to the BSC or to the higher/lower level BTS to completestar, tree, and chain connections.
2) Operation and maintenance unit (OMU)
The OMU module is the core control and processing center of the TMU. Through the
OMU, performance parameters of various BIU and MCK units can be directly
configured.
The OMU receives fault alarms, handles fault management, and communicates via
internal control buses with the CPU of various units (TRX, CDU, PMU, TES, etc.) in
the BTS, so as to complete the operation and maintenance of the whole system.
It collectively loads and saves the software of various BTS units before loading
software for each unit according to demands. Moreover, it supports the Man-Machine
Interface (MMI) connecting to the PC.
The Flash memory of the OMU module can store two different versions of BTS
software. One is the software currently used by the BTS and the other one is the
previous BTS software. It can load either version according to the requirements to
each board.
When the software on the BTS needs to be upgraded, the new version can be loaded
from the BSC through OML and saved on the OMU to replace the old version.
Meanwhile, the OMU keeps the original software version of the BTS as a backup, in
case the loading should fail.
3) Main clock module (MCK)
The MCK is configured with an OCXO (oven controlled crystal oscillator) compliant
with the stratum 3 A standard, and phase-locking and frequency-division circuits.
According to system configuration, the MCK can work in the free-run mode or
software phase-locked mode to output a reference clock SREF with a stability better
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1) Power supply module
The power supply module of the TES board includes two parts, the DC/DC
conversion circuit and the DC/AC conversion circuit. The DC/DC conversion circuit
converts two +24V DC supplies into +5V DC and one +24V DC supply into 5V DC.The DC/AC conversion circuit converts +24V DC into 75V AC ringing current.
The ringing current is featured by high performance ringing current signal sources,
sine wave output, low distortion, light weight, and high power density. Its output
voltage is 75V AC, and its output current is 40mA, with a standard tone of 25Hz.
Note:Figure 2-9 shows that TES can provide power for 2 TEU boards. So one TEU board can be configured
in the 6 carrier cabinets of M900/ M1800 BTS312, and two TEU boards in 12 carrier cabinets.
2) Communication module
The main function of the communication module is to handle the communication
between TES and TMU, between TES and TEU, and to acquire the PCB version No.
and cabinet No. of the TES board.
The serial port communication between TES and TMU is implemented through
RS485 standard. TES is connected with CBUS3 via the level conversion circuit. The
serial port communication between TES and TEU adopts the point-to-point mode,
with the serial port level as the TTL level.
Communication with TMU mainly includes reporting transmission network information
and transmission board information from TEU to TMU, as well as reporting TES board
status information to TMU.
Communication with TEU is mainly to acquire transmission network and base station
transmission board information.
III. Indices
The board's size is 280mm233mm, occupying one standard board position.
2.3.5 ASU
Due to the complexity of network, the base station is required to support multiple
external interfaces and flexible networking modes.
Besides the E1 interfaces, M900/M1800 BTS312 also has the built-in transmission
system. It supports the 155M SDH optical interfaces. All these interfaces are provided
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z Orderwire: 1
z Ethernet interface: 1
z User RS232 port (point to point): 1
z
Network management interface: Ethernet/RS232
2.3.6 ABB
I. General
In practice, chain networking is usually adopted in BSS networking. This networking
mode has the advantage of simple structure and low cost, but also it has the
disadvantage that when power failure occurs at a site, all services of the downstream
sites will be interrupted. ABB provides of Abis interface bypass function as a solution
to the problem above.
II. Functions
ABB is applied in the environment of BTS chain networking. It is in charge of the BTS
transmission trunk. When power failure occurs at a certain level (in the middle) of
BTS in the chain networking, ABB will bypass the Abis transmission line off this site,
and directly connect it to the downstream BTS. In this way, even if power failure
occurs at the middle level site in chain networking environment, the services of the
downstream site will not be affected. See Figure 2-10.
BSCABB
TMU
ABB
TMU
ABB
TMU
Site1 Site2 Site3
Figure 2-10ABB working principle
ABB can also perform loop back at the transmission line, so that in the case of powerfailure at the last level BTS, ABB will loop back the E1 signal for BSC to detect the
quality of the entire transmission link.
III. Location of Board
ABB shares the same slot with TEU, therefore the size of the board and the interface
definition is consistent with TEU. BTS312 has two TEU slots, but ABB can only select
the TEU0 slot.
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2.3.7 ABA
I. General
ABA realizes the communication between ABB and TMU. ABB communicates with
TMU via CBUS3. But the slot of ABB does not provide the connection with CBUS3.
Therefore, ABA is used to provide the connection between them. Via ABA, part of the
signals from ABB (e.g. the signals of ABA on position) can be transmitted to CBUS3
on the backplane of common resource frame.
II. Location of Board
ABA shares the same slot with TES in BTS312, therefore the size of the board and
the interface definition is consistent with TES.
2.4 Other Parts of the Cabinet
2.4.1 TDU
The TDU is at the top of BTS cabinet, serving as the control center of BTS clock
transfer. It receives the clock source (SREF, OBCLK, FCLK, FN) from TMU, and
forwards the clock source to the TRXs in this cabinet and the parts in other cabinets.
TDU can also transfer other signals (e.g. alarm signals).
The main functions of the TDU are:
Provides bus-control interface
1) Clock Bus
In the simplex RS485 bus structure, it distributes the clocks generated by the active
TMU in the basic cabinet to various extension cabinets, The clock signal process is
shown in Figure 2-11.
TMU TDUBoards in the maincabinet
Boards in theextension cabinet
A-bis
Figure 2-11BTS clock signal process
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The TDU of each cabinet is connected to the bus. After receiving clock signals, it
transfers them to the TRX in the local cabinet.
The TDU of the last cabinet is connected to an adapter. All the TDUs form a
chrysanthemum ring of a clock bus, as shown in Figure 2-12.
UDC
UDC
U
DC
U
DC
U
DC
U
DC
M
P
P S UU U
T
XR
XR
XR
T
XR
P S U M
T T T
UDC
UDC
U
DC
U
DC
DC
DC
U U
UMP
U
M
T
Extension Cabinet Basic Cabinet
XR
XR
XR
T
XR
T T T
X X XR
T
XR
T T T
R R
X XR
XR
T
XR
T T T
XR
XR
XR
T
XR
T T T
X X XR
T
XR
T T T
R R
R
Figure 2-12Clock bus connection in a synchronous cell
2) Data Bus (DBUS)
DBUS is for the data connection between TMU and TRX. Each TMU provides 2 full
duplex DBUS link and TRX connection, called DBUS1 and DBUS2.
The physical feature of DBUS is differential RS485, TDMA synchronous bus and
distribution of 32 timeslots is similar to that of PCM.
The active TMU has DBUS connections to each TRX in the same cabinet. The active
and standby links are led from the main cabinet to the 24 TRXs in the local cabinet
group. There is no
top related