Huawei ODU3601C-800 Users Manual

User Manual iSiteC ODU3601C CDMA Soft Base Station

System Description

Table of Contents

Chapter 1 System Overview .................................................................................................1-1

1.1 Introduction...............................................................................................................1-1

1.1.1 Network Solution of cdma2000 1X System........................................................1-1

1.1.2 Market Orientation of ODU3601C......................................................................1-3

1.2 System Feature.........................................................................................................1-3

1.3 Technical Index.........................................................................................................1-4

1.3.1 Engineering Index............................................................................................1-5

1.3.2 Protection Index...............................................................................................1-5

1.3.3 Performance Index...........................................................................................1-5

1.4 External Interface.......................................................................................................1-6

1.4.1 Um Interface....................................................................................................1-6

1.4.2 Baseband Data Interface..................................................................................1-9

1.4.3 Other Interface...............................................................................................1-10

1.5 Reliability Design.....................................................................................................1-10

1.5.1 Hardware Reliability Design............................................................................1-10

1.5.2 Software Reliability Design .............................................................................1-12

Chapter 2 Hardware Architecture.........................................................................................2-1

2.1 Overview...................................................................................................................2-1

2.1.1 Appearance.....................................................................................................2-1

2.1.2 Functional Structure.........................................................................................2-2

2.2 MTRM.......................................................................................................................2-2

2.2.1 Structure and Principle.....................................................................................2-3

2.2.2 External Interface.............................................................................................2-5

2.2.3 Key Index........................................................................................................2-6

2.3 MPAM.......................................................................................................................2-6

2.3.1 Structure and Principle.....................................................................................2-6

2.3.2 External Interface.............................................................................................2-8

2.3.3 Key Index........................................................................................................2-8

2.4 MFEM.......................................................................................................................2-8

2.4.1 Structure and Principle.....................................................................................2-8

2.4.2 External Interface.............................................................................................2-9

2.4.3 Key Index......................................................................................................2-10

2.5 MAPM.....................................................................................................................2-10

2.5.1 Structure and Principle...................................................................................2-10

2.5.2 External Interface...........................................................................................2-11

2.5.3 Key Index......................................................................................................2-11

2.6 MBKP.....................................................................................................................2-11

User Manual iSiteC ODU3601C CDMA Soft Base Station

2.7 Antenna and Feeder Subsystem...............................................................................2-12

System Description

Table of Contents

Chapter 3 System Function..................................................................................................3-1

3.1 RF Functions.............................................................................................................3-1

3.1.1 Power Control..................................................................................................3-1

3.1.2 Handoff...........................................................................................................3-3

3.1.3 Cell Breath ......................................................................................................3-3

3.1.4 Diversity Reception..........................................................................................3-4

3.1.5 Radio Configuration and Channel Support.........................................................3-4

3.2 Maintenance Function................................................................................................3-9

3.3 Lightning Protection.................................................................................................3-10

3.3.1 Lightning Protection for Power Supply.............................................................3-10

3.3.2 Lightning Protection for Antenna and Feeder System.......................................3-11

3.4 Configuration and Networking...................................................................................3-12

3.4.1 Cabinet Configuration.....................................................................................3-12

3.4.2 Site Configuration ..........................................................................................3-13

3.4.3 ODU3601C Networking..................................................................................3-14

Appendix A Performance of Receiver and Transmitter .......................................................A-1

A.1 Performance of Receiver .......................................................................................... A-1

A.1.1 Frequency Coverage ......................................................................................A-1

A.1.2 Access Probe Acquisition................................................................................ A-1

A.1.3 R-TCH Demodulation Performance..................................................................A-1

A.1.4 Receiving Performance................................................................................... A-8

A.1.5 Limitation on Emission.................................................................................... A-9

A.1.6 RSQI .............................................................................................................A-9

A.2 Performance of Transmitter..................................................................................... A-10

A.2.1 Frequency Requirement................................................................................ A-10

A.2.2 Modulation Requirement............................................................................... A-10

A.2.3 RF Output Power Requirement...................................................................... A-11

A.2.4 Limitation on Emission.................................................................................. A-11

Appendix B EMC Performance............................................................................................B-1

B.1 EMI Performance.....................................................................................................B-1

B.2 EMS Performance.................................................................................................... B-2

Appendix C Environment Requirement...............................................................................C-1

C.1 Storage Environment................................................................................................C-1

C.2 Transportation Environment......................................................................................C-2

C.3 Operation Environment.............................................................................................C-4

Appendix D Electromagnetic Radiation...............................................................................D-1

D.1 Introduction..............................................................................................................D-1

D.2 MPE........................................................................................................................D-1

D.3 Estimation of Exposure to Electromagnetic Field........................................................D-3

D.4 Calculation of Safe Distance.....................................................................................D-3

User Manual iSiteC ODU3601C CDMA Soft Base Station

D.4.1 S = power density [W/m2] see also MPE Limits.................................................D-4

System Description

Table of Contents

D.5 Location of BTS Antenna..........................................................................................D-4

D.5.1 Exclusion Zone...............................................................................................D-4

D.5.2 Guidelines on Selecting Antenna Location .......................................................D-4

Appendix E Standard Compliance.......................................................................................E-1

E.1 General Technical Specification................................................................................ E-1

E.2 Um Interface............................................................................................................ E-1

E.3 Abis Interface...........................................................................................................E-1

E.4 Lightning Protection.................................................................................................. E-2

E.5 Safety...................................................................................................................... E-3

E.6 EMC........................................................................................................................E-3

E.7 Environment.............................................................................................................E-5

Appendix F Abbreviation..................................................................................................... F-1

F.1 Abbreviation of Modules............................................................................................ F-1

F.2 Glossary.................................................................................................................. F-1

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User Manual iSiteC ODU3601C CDMA Soft Base Station

Chapter 1 System Overview

System Description

Chapter 1 System Overview

1.1 Introduction

The Mobile Communication System has experienced the first generation (analog system) and the second generation (digital system). As the one of the main development trends of the second generation, cdma2000 1X mobile communication system has been widely used for commercial purpose.

This section first introduces the network solution of Huawei cdma2000 1X mobile communication system, and then the market orientation of Huawei base station ODU3601C.

1.1.1 Network Solution of cdma2000 1X System

The cdma2000 1X mobile communication system comprises the Base Station Subsystem (BSS) and the Core Network (CN).

The BSS comprises the Base Transceiver Station (including ODU3601), Base Station Controller (BSC), and Packet Control Function (PCF) which is usually integrated with BSC.

The CN comprises the packet domain network and circuit domain network. The equipment of packet domain interworks with Internet, and that of the circuit domain interworks with the conventional PLMN and PSTN/ISDN.

The system's operation and maintenance is implemented via Huawei integrated mobile network management system iManager M2000.

Position of ODU3601C in the network is shown in Figure 1-1. 　

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User Manual iSiteC ODU3601C CDMA Soft Base Station

MSMS

ODU3601C

ODU3601CODU3601C

ODU3601C

ODU3601CODU3601C

ODU3601C

ODU3601CODU3601C

cBTS3612

cBTS3612cBTS3612

cBTS3612

cBTS3612cBTS3612

BTS3601C

BTS3601CBTS3601C

MS: Mobile Station BSC: Base Station Controller ISDN: Integrated Services Digital Network PLMN: Public Land Mobile Network PSTN: Public Switched Telephone Network PCF: Packet Control Function BSS: Base Station Subsystem CN: Core Network

Mobile integrated

management system

BTS3601C

BTS3601CBTS3601C

BSC/PCF

Abis

A3/A7

cBTS3612

cBTS3612cBTS3612

Abis

BSC/PCF

BSS CN

A10/A11

A1/A2

System Description

Chapter 1 System Overview

Packet domain

network equipment

Circuit domain

network equipment

Internet

PLMN

PSTN/ISDN

Figure 1-1 Network structure of Huawei cdma2000 1X mobile communication system

l ODU3601C

ODU3601C is an outdoor one-carrier soft base station. It shares the baseband processing resource and main control clock resource with its upper-level BTS. It implements radio signal transmission and reception together with the upper-level BTS under the control of BSC.

l BTS3601C

BTS3601C is an outdoor one-carrier BTS. It transmits/receives radio signals so as to realize the communication between the radio system and the Mobile Station (MS).

l cBTS3612

cBTS3612 is a set of indoor BTS equipment. The maximum capacity of single cabinet contains 12 sector carriers. Same with BTS3601C, it also transmits/receives radio signals to accomplish the communication between the radio system and the MS.

l Base Station Controller (BSC)

BSC performs the following functions: BTS control and management, call connection and disconnection, mobility management, power control, and radio resource management. It provides stable and reliable radio connections for the upper-level services through soft/hard handoff.

l Packet Control Function (PCF)

PCF is used for the management of Radio-Packet (R-P) connection. As radio resources are limited, they should be released when subscribers are not sending or

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receiving information, but the Point-to-Point Protocol (PPP) connection must be maintained. PCF shields the radio mobility against the upper-level services through the handoff function.

l Mobile Station (MS)

MS is a set of mobile subscriber equipment that can originate and receive calls, and can communicate with BTS.

1.1.2 Market Orientation of ODU3601C

Huawei ODU3601C is fully compatible with IS-95A/B and IS-2000 standards. As illustrated in Figure 1-1, ODU3601C is located between other BTS (such as

BTS3601C and cBTS3612) and the MS. It is connected to the upper-level BTS (master BTS) with optical fibers, equivalent to the function of the Radio Frequency (RF) module of the upper-level BTS installed far away.　

ODU3601C is an outdoor base station, configured with only one carrier. It features small size, easy installation, flexible networking, less investment and fast network construction. ODU3601C can be used in residential quarters and urban hot spots / blind spots, and provide small-capacity wide-coverage for remote areas (such as rural area, grassland, highway, scenic spots).

System Description

Chapter 1 System Overview

ODU3601C shares the clock resource of the upper-level BTS, so no satellite antenna is needed. This feature makes ODU3601C an attractive application in indoor and underground environment where the installation of satellite antenna is difficult. 　

1.2 System Feature

I. Easy installation

Featuring small size, light weight and mains supply, ODU3601C does not require an equipment room or air conditioner. It neither requires a special tower as it can be easily installed on a metal post, stayed tower or on the wall. All these can reduce the site construction cost without affecting the network quality.

II. Wide application scope

ODU3601C is dust-proof, anti-burglary, water-proof, and damp-proof. With its protection performance in compliance with the IP55 (IEC 60529: Degrees of protection provided by enclosure), it operates normally in different whether conditions.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

III. Flexible coverage schemes

ODU3601C shares the baseband subsystem of master BTS for service processing. The I/Q digital modulated signals are transmitted between the ODU3601C and the master BTS through the optical fibers. ODU3601C supports various cascading methods with the master BTS to achieve flexible network coverage.　

The cascading distance can be either 10km or 70km, depending on the optical interface module used. For BTS3601C, total two ODU3601Cs can be cascaded, and the second ODU3601C can be placed 60km away. For cBTS3612, total six ODU3601Cs can be cascaded, and the sixth ODU3601C can be placed 90km away. 　

IV. Synchronization within the whole network

By adopting the automatic delay compensation technique developed by Huawei, the master BTS provides ODU3601C with precise clock synchronization signals via optical fibers. No GPS antenna is needed. This ensures synchronization within the whole network and lowers call drop ratio during handoffs.

System Description

Chapter 1 System Overview

V. Unified network planning

Though a logical base station, ODU3601C can be regarded as a normal entity in network planning, as it can be upgraded to be an independent cBTS3601C by adding the Micro-bts Baseband Processing Module (MBPM).

VI. Softer handoff

ODU3601C and the master BTS may cover neighboring cells. As the baseband processing of ODU3601C is implemented by the resource pool of the master BTS, the co-frequency handoff between the ODU3601C and the master BTS is the softer handoff.

VII. Support for multi-bands

ODU3601C supports 450MHz and 800MHz bands, therefore, it can be applied in the 450MHz communication system and the 800MHz communication system.

1.3 Technical Index

The technical indices include engineering, protection and performance indices. The engineering indices include power supply, power consumption, weight,

dimensions and other indices involved in engineering installation. The protection indices refer to the capabilities of the main external interfaces agains t

surge current.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

The performance indices refer to the technical parameters of its receiver/transmitter and the reliability indices of the whole system.

System Description

Chapter 1 System Overview

1.3.1 Engineering Index

Power supply

Power consumption

Weight

Operation environment

Cabinet dimensions

(height%width%depth)

1.3.2 Protection Index

E1 interface

RF feeder interface

AC power supply interface

(for connecting AC lightning

protection box)

Satellite feeder interface (for

connecting lightning arrestor

for satellite feeder)

~220V (150~300V AC) <300W (In normal temperature, while the heating plate is not working) 　

<500W (In low temperature, while the heating plate is working) <40kg

Temperature: -40âC~55âC Relative humidity 5%~100%

700mm%450mm%330mm

Differential mode 5kA, or common mode 10kA surge current Differential mode 8kA, or common mode 8kA surge current

Differential mode 40kA, or common mode 40kA surge current

Differential mode 8kA, or common mode 8kA surge current

1.3.3 Performance Index

I. Transmission

l 450MHz band

Working frequency

Channel bandwidth

Channel precision

Frequency tolerance Ÿ!

l 800MHz band

Transmit power

460~470MHz

1.23MHz 25kHz

0.05ppm

20W (the maximum value measured at the cabinet-top feeder port)

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User Manual iSiteC ODU3601C CDMA Soft Base Station

Frequency coverage

Channel bandwidth

System Description

Chapter 1 System Overview

869Ã894MHz

1.23MHz

Channel step length

Frequency tolerance Ÿ!

Transmit power

II. Reception

l 450MHz band

Signal receiving sensitivity

Working frequency

Channel bandwidth

Channel precision

l 800MHz band

Working frequency Channel bandwidth Channel step length

30kHz

0.05ppm

20W (the maximum value measured at the cabinet-top feeder port)

450Ã460MHz

1.23MHz 25kHz

-127dBm (RC3, and main and diversity reception)

824Ã849MHz

1.23MHz 30kHz

Signal receiving sensitivity

III. System reliability

Mean Time Between Failures

(MTBF)

Mean Time To Repair (MTTR) Ÿ

Availability ¦

1.4 External Interface

1.4.1 Um Interface

I. Overview

In Public Land Mobile Network (PLMN), MS is connected with the fixed part of the network through the radio channel. The radio channel allows the subscribers to be connected with the network and to enjoy telecommunication services.

-128dBm (RC3, and main and diversity reception)

100,000 hour

1 hour

99.999%

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User Manual iSiteC ODU3601C CDMA Soft Base Station

To implement interconnection between MS and BSS, systematic rules and standards should be established for signal transmission on radio channels. The standard for regulating radio channel signal transmission is called radio interface, or Um interface.

Um interface is the most important interface among the many interfaces of CDMA system. Firstly, standardized radio interface ensures that MSs of different manufacturers are fully compatible with different networks. This is one of the fundamental conditions for realizing the roaming function of CDMA system. Secondly, radio interface defines the spectrum availability and capacity of CDMA system.

Um interface is defined with the following features:

l Channel structure and access capacity. l Communication protocol between MS and BSS. l Maintenance and operation features. l Performance features. l Service features.

II. Um interface protocol model

System Description

Chapter 1 System Overview

Um interface protocol stack is in 3 layers, as shown in Figure 1-2.

Figure 1-2 Um interface layered structure

Layer 1 is the physical layer, that is, the bottom layer. It includes various physical channels, and provides a basic radio channel for the transmission of higher layer information.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

Layer 2 is the data link layer, including Medium Access Control (MAC) sublayer and Link Access Control (LAC) sublayer. The MAC sublayer performs the mapping between logical channels and physical channels, and provides Radio Link Protocol (RLP) function. The LAC sublayer performs such functions as authentication, Automatic Repeat Request (ARQ), addressing and packet organization.

Layer 3 is the top layer. It performs Radio Resource Management (RM), Mobility Management (MM) and Connection Management (CM) through the air interface.

III. Physical layer

1) Working band

Band Forward band Reverse band Duplex spacing Channel width Carrier spacing

450MHz 460 - 470MHz 450 - 460MHz 10MHz 1.23 MHz 1.25 MHz 800MHz 869 - 894 MHz 824 - 849 MHz 45MHz 1.23 MHz 1.23 MHz

2) Physical layer function

l Service bearer: the physical channel in the physical layer provides bearer for the

logical channel of the higher layer.

l Bit error check: the physical layer provides transmission service with error

protection function, including error checking and error correction.

l User identification: the physical layer provides an exclusive ID for every user by

code division.

3) Radio configuration

System Description

Chapter 1 System Overview

The physical layer supports multiple Radio Configurations (RCs). Different RCs support different traffic channel data rates. For detailed introduction, please refer to Section 3.1.5 Radio Configuration and Channel Support.

IV. Data link layer

Data link layer at Um interface includes two sublayers, MAC and LAC. The purpose of introducing MAC and LAC is to:

l Support higher level services (signaling, voice, packet data and circuit data). l Support data services of multiple rates. l Support packet data service and circuit data service of higher quality (QoS). l Support multi-media service, that is, processing voices, packet data and circuit

data of different QoS levels at the same time.

1) MAC sublayer To support data service and multi-media service, cdma2000 1X provides powerful

MAC layer to ensure the reliability of services. MAC layer provides two important functions:

l Radio Link Protocol (RLP), ensuring reliable transmission on the radio link.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

l Multiplex function and QoS function, with diversified services and higher service

quality.

2) LAC sublayer LAC layer performs such functions as Automatic Repeat Request (ARQ),

authentication and addressing.

V. Layer 3

The higher layer signaling performs the functions such as radio resource management, mobility management and call connection management on air interface.

1) Radio resource management The radio resource management functions include:

l Radio channel management

It is used to establish, operate and release radio channels, and help to realize soft handoff, softer handoff and hard handoff.

System Description

Chapter 1 System Overview

l Power control

Various power control technologies are used on Um interface to reduce the system interference and improve the system capacity.

2) Mobility management It is used to support the mobility features of the mobile subscriber, performing such

functions as registration, authentication and Temporary Mobile Subscriber Identity (TMSI) re-allocation.

3) Connection management It is used to setup, maintain and terminate calls.

1.4.2 Baseband Data Interface

ODU3601C communicates with the upper-level BTS through the baseband processing interface.

This interface adopts optical fibers to transmit I/Q digital modulated signals, and supports various cascading modes. For details, please refer to Section 1.2 System Feature.

The baseband data interface adopts automatic delay compensation technique. The precise clock synchronization signal is provided by the master BTS through the optical fiber.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

1.4.3 Other Interface

I. Test interface

The test interface provides 10MHz and 2s signals through MTRM that may be needed for test instruments.

II. Power supply interface

ODU3601C supports 220V AC power supply. It provides external 220V AC interface and 24V DC battery interface.

1.5 Reliability Design

Reliability design of a system is shown in the stability and reliability of the product during operation.

Huawei ODU3601C is designed based on the following standards:

System Description

Chapter 1 System Overview

l TIA/EIA/IS-95A CDMA Radio Interface Specifications l TIA/EIA/IS-95B CDMA Radio Interface Specifications l TIA/EIA/IS-2000 CDMA Radio Interface Specifications l TIA/EIA/IS-97D CDMA Base Station Minimum Performance Standard l Huawei product reliability design index and related technical specifications

With various measures taken, the design of boards is in strict accordance with the requirement of above standards pertaining to reliability.

1.5.1 Hardware Reliability Design

I. De-rating design

To improve system reliability and prolong the service life of components, components are carefully selected and strictly tested, and less stress (electrical stress and temperature stress) is to be borne in actual operation than its designed rating.

II. Selection and control of component

The category, specifications and manufacturers of the components are carefully selected and reviewed according to the requirements of the product reliability and maintainability. The replace ability and normalization of components is one of the main factors for the decision, which help to reduce the types of components used and hence improve the availability of the system.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

III. Board level reliability design

Many measures have been taken in board design to improve its reliability. Redundancy configuration is applied for key components to improve system reliability.

l Key circuits are designed by Huawei, which lays the foundation of high reliability. 　 l The hardware WATCHDOG is equipped for the board, and the board can

automatically reset in case of fault. 　

l The board is provided with the functions of over-current and over-voltage

protection and the function of temperature detection. 　

l Strict thermal analysis and simulation tests are conducted during the design of

boards for the purpose of ensuring longtime operation. 　

l The board software and important data is stored in the non-volatile memory, so

that the board can be restarted when software upgrading fails. 　

IV. Fault detection, location and recovery

The BTS system is equipped with the functions of self-detection and fault diagnosis that can record and output various fault information. Common software and hardware faults can be corrected automatically. 　

System Description

Chapter 1 System Overview

The hardware fault detection functions include fault locating, isolating and automatic switchover. The maintenance engineers can identify the faulty boards easily with the help of the maintenance console. 　

The ODU3601C system also supports the reloading of configuration data files and board execution programs.

V. Fault tolerance and exceptional protection

When faults occur, the system usually will not be blocked. The system will make a final confirmation on a hardware fault through repeated

detection, thus avoiding system reconfiguration or QoS deterioration due to contingent faults.

VI. Thermal design

The influence of temperature on the ODU3601C has been considered in the design. Thermal design primarily concerns the selection of components, circuit design

(including error tolerance, drift design and derating design), structure design and heat dissipation, so that the ODU3601C can work reliably in a wide range of temperatures.

The first consideration in thermal design is to balance the heat distribution of the system. Corresponding measures are taken in the place where heat is more likely to be accumulated.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

VII. Maintainability

The purpose of maintainability design is to define the workload and nature of the maintenance, so as to cut the maintenance time. The main approaches adopted include standardization, modularization, error prevention, and testability improvement, which can simplify the maintenance work.

VIII. EMC design

The design ensures that ODU3601C will not degrade to an unacceptable level due to the electromagnetic interference from other equipment in the same electromagnetic environment. Neither the ODU3601C will cause other equipment in the same electromagnetic environment to degrade to an unacceptable level.

IX. Lightning protection

To eliminate the probability of lightning damage on the ODU3601C system, proper measures are taken with respect to the lightning protection for DC power supply and antenna & feeder system. For details, please refer to "3.3 Lightning Protection".

System Description

Chapter 1 System Overview

1.5.2 Software Reliability Design

Software reliability mainly includes protection performance and fault tolerance capability.

I. Protection performance

The key to improve software reliability is to reduce software defects. Software reliability of ODU3601C is ensured through the quality control in the whole process from system requirement analysis, system design to system test.

Starting from the requirement analysis, software development process follows the regulations such as Capability Mature Mode (CMM), which aim to control faults in the initial stage.

In software design, much attention is devoted to the designing method and implementation: the software is designed in a modular structure, and in a loose coupling mechanism. When a fault occurs to one module, other modules will not be affected. In addition, preventive measures such as fault detection, isolating and clearing are also applied to improve the system reliability. Other effective methods include code read-through, inspection, and unit test.

Various software tests are conducted to improve the software reliability. Test engineers participate the whole software development process, from unit test to system test. They make plans strictly following the demand of the upper -level flow,

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which ensure the improvement of software reliability. Additionally, test plans are modified and improved with the tests.

II. Fault toler ance capability

Fault tolerance capability of the software system me ans that the whole system would not collapse when a minor software fault occurs. That is, the system has the self-healing capability. The fault tolerance of BTS3601 software is represented in the following aspects:

l All boards work on a real-time operating system of high reliability. l If software loading fails, the system can return to the version that was

successfully loaded last time.

l Important operations are recorded in log files. l Different authority levels are provided for operations, so as to prevent users from

performing unauthorized operations.

l Warnings are given for the operations that will cause system reboot (such as

reset operation). The operator is required to confirm such operations.

System Description

Chapter 1 System Overview

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User Manual iSiteC ODU3601C CDMA Soft Base Station

Chapter 2 Hardware Architecture

System Description

Chapter 2 Hardware Architecture

2.1 Overview

2.1.1 Appearance

I. Cabinet appearance

Figure 2-1 shows the appearance of an ODU3601C cabinet. The cabinet dimensions are: 700mm % 450mm % 330mm (height % width % depth).

Figure 2-1 ODU3601C cabinet

II. Cabinet feature

l Excellent electrical conductivity and shielding effect. l Equipped with thermal tube for heat exhaustion, free of noise l Water-proof, sun-screening, anti-burglary features make it suitable for outdoor

installation.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

l Small size, light weight and attractive appearance. l Modular structure, making installation and maintenance easy.

System Description

Chapter 2 Hardware Architecture

2.1.2 Functional Structure

The ODU3601C has a compact and highly integrated structure. It consists of Micro-bts Transceiver Module (MTRM), Micro-bts Power Amplifier Module (MPAM), Micro-bts Radio Frequency Front End Module (MFEM), Micro-bts Ac-dc Power supply Module (MAPM), and the antenna & feeder system.

The functional structure is shown in Figure 2-2.

Optical

BTS or ODU3601C

ODU3601C

220VAC

MTRB: Micro-bts Transceiver Board MTRM: Micro-bts Transceiver Module MPAU: Micro-bts Power Amplifier Unit MMCB: Micro-bts Monitor & Control Board MPAM: Micro-bts Power Amplifier Module MAPM: Micro-bts Ac-dc Power Supply Module MRDU: Micro-bts Divide And Duplexer Receive Filter Unit MFEM: Micro-bts Radio Frequency Front End Module MLNA: Micro-bts Low-Noise Amplifier

fier

Optical fier

Heating plate

MTRB

MTRM

MAPM

RS485

+27VDC

RS-485

TX RXM RXD

MPAU

MPAM

MMCB

MFEM

MRDUMLNA

Figure 2-2 Functional structure of ODU3601C

ODU3601C performs the functions of RF signal transceiving and amplification, and the conversion of baseband signals. The functions of various modules are detailed in the following sections.

2.2 MTRM

Micro-bts Transceiver Module (MTRM) consists of MTRB and heating plate. The heating plate ensures that MTRB can start and operate normally in low

temperature. MTRB modulates/demodulates baseband I/Q signals, performs up/down conversion,

and supports the function of cascading via optical fiber.

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User Manual iSiteC ODU3601C CDMA Soft Base Station

2.2.1 Structure and Principle

MTRM consists of Micro-bts Intermediate Frequency Unit (MIFU) and Micro-bts Radio up-down Converter Unit (MRCU).

The functional structure is shown in Figure 2-3.

System Description

Chapter 2 Hardware Architecture

MRCU

Main receiver

Diversity receiver

Local oscillator

Transmiter

MPAM

MPAM MAPM

MAPM

BTS or ODU3601C

ODU3601C

MAPM

MIFU

RS485

RS485 RS485

RS485

Optical interface sub-unit

+27V

Control

Control sub-unit

sub-unit

CPU

FIR

DAGC

Section multiplexer

FIR

Down

converter

Down

converter

MAPM

Clock sub-unit

ADC

DAC

Filter

Heating plate

Figure 2-3 Functional structure of MTRM

I. MIFU

MIFU consists of up converter, down converter, multiplexer/demultiplexer, optical interface, clock, CPU, and power supply sub-units. It is in charge of the conversion between analog intermediate frequency signals and digital baseband signals, and the control of MTRB. 　

MFEM

MHPA

l Up converter

The up converter accomplishes wave filtering, digital up conversion and digital-analog conversion of the signals in the transmit path.

On receiving the baseband I/Q signals that have been de-multiplexed, it performs digital up conversion after baseband filtering. Then the digital intermediate frequency signals are converted into analog intermediate frequency signals after digital-analog conversion and wave filtering. At last, the analog intermediate frequency signals are sent to the transmitter in MRCU through Radio Frequency (RF) interface.

l Down converter

The down converter accomplishes the analog-digital conversion, digital down conversion and baseband filtering of the signals in the receive path.

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On receiving the analog intermediate frequency signals from the radio interface, it converts them into digital intermediate frequency signals via analog-digital conversion. Then the digital intermediate frequency signals are converted into baseband I/Q signals via digital down conversion and baseband filtering. As last, the I/Q signals are transmitted to the demultiplexer/multiplexer.

l Demultiplexer/multiplexer

Under the control of the CPU, the demultiplexer/multiplexer de-multiplexes the forward I/Q signals, and multiplexes the reverse I/Q signals. At the same time, it multiplexes/de-multiplexes the Operation & Maintenance (O&M) signals of the OML.

l Optical interface sub-unit

This sub-unit consists of two optical interface modules. The optical interface modules perform channel coding/decoding, and accomplish optical-electrical and electrical-optical signal conversion. They are respectively connected with upper-level BTS (or ODU3601C) and the lower-level ODU3601C to realize optical fiber cascading.

System Description

Chapter 2 Hardware Architecture

If the upper-level BTS is cBTS3612, this optical interface sub-unit is connected to the BTS Resource Distribution Module (BRDM) optical interface of cBTS3612. If the upper-level BTS is BTS3601C or ODU3601C, it is connected to the Micro-bts Transceiver Module (MTRM) optical interface of BTS3601C or ODU3601C.

l Clock sub-unit

The clock sub-unit generates all the clocks needed by MIFU, including the clocks for up/down conversion, analog-digital conversion (ADC), and digital-analog conversion (DAC). At the same time, it also provides the reference clock for the MRCU.

l CPU

The CPU is in charge of the control of MTRB, including the initialization upon power-on, alarm collecting and reporting, and processing related O&M messages. The O&M messages are received from or sent to the upper-level BTS by the multiplex/demultiplex sub-unit of the digital MIFU.

l Control sub-unit and heating plate

The control sub-unit and the heating plate enable MTRM to start and normally operate in low temperature.

When the internal module temperature is lower than -5âC, the heating plate will be first started to heat the module. Other boards of the module will not be powered unless the module temperature rises to the set value.

l Power supply sub-unit

With input voltage of +27V, the power supply sub-unit provides power to MIFU and MRCU.

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II. MRCU

MRCU consists of transmitter, main/diversity receiver and local oscillator. It up-converts, amplifies, and performs spurious-suppressive wave filtering for the intermediate frequency signals output by MIFU. It also performs analog down-conversion, amplification, channel-selective wave filtering and receiving noise factor control over the main/diversity receiving signal input from the MFEM. 　

l Transmitter

On receiving the modulated analog intermediate frequency signals output by MIFU, the transmitter converts them to specified RF band after two times of up conversions. Before and after the up conversion, wave filtering, signal amplification and power control are performed so as to ensure that the output RF signals meet the protocol requirements on power level, Adjacent Channel Power Radio (ACPR) and spuriousness.

l Main/diversity receiver

The main/diversity receiver converts the RF signals output by MFEM to specified intermediate frequency signals via down conversion, and performs wave filtering, signal amplification and power control before and after the down conversion, so as to ensure that the intermediate frequency signals output can be received by MIFU.

System Description

Chapter 2 Hardware Architecture

l Local oscillator

The local oscillator consists of the intermediate frequency source and transmit/receive RF synthesizer. The intermediate frequency source generates the local frequency signals for intermediate frequency up conversion in transmit path. The RF synthesizer generates the local frequency signals for the up- conversion of the transmit path and the local frequency signals for the down conversion of main/diversity receive path.

2.2.2 External Interface

There are interfaces between MTRM and MPAM/MFEM, upper-level BTS, lower -level ODU3601C and power supply module.　

l RF interface to MPAM

The RF transmitting signal is output via this interface to MPAM, where the signal is amplified and then output.

l RF interface to MFEM

The main/diversity RF receiving signal output by MFEM is received via this interface.

l Optical interface to upper-level BTS (or ODU3601C)

Through this interface, the ODU3601C shares the baseband processing resources of upper-level BTS, and performs the functions of receiving configuration messages, reporting alarm information, etc.

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And the ODU3601C can also be casecaded to the upper-level ODU3601C through this interface.

l Optical interface to MTRM of lower-level ODU3601C

This interface is used to cascade ODU3601C.

l Alarm interface

MTRM is connected with MBKP through a connector. It collects the alarm information through the RS485 serial bus on MBKP sent by other modules, sends the information through the optical interface to the upper-level BTS.

This interface is also used to transmit control signals and power detection signals for MPAM.

l Power supply interface

This interface is used to supply power to MTRM. 　

2.2.3 Key Index

System Description

Chapter 2 Hardware Architecture

l Supported band: 450MHz band and 800MHz band l Power supply: +27V DC l Power consumption of MTRB: 40W; Power consumption of heating plate: 110W l Module size: L % W % T = 430mm % 250mm % 65mm

2.3 MPAM

2.3.1 Structure and Principle

Micro-bts Power Amplifier Module (MPAM) consists of Micro-bts Power Amplifier Unit (MPAU) and Micro-bts Monitor & Control Board (MMCB).

The structure is shown in Figure 2-4.

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MTRM

MTRM RF input

RF input

MAPM

MTRM

+27V

RS-485

Linear power

amplifier

MCU

Alarm circuit

Linear power

MPAU

A/D

MMCB

amplifier

System Description

Chapter 2 Hardware Architecture

Antenna

Transmit power

detection

Figure 2-4 Structure of MPAM module

I. MPAU

MPAU consists of two parts: linear power amplifier and alarm circuit. The power amplifier amplifies the RF signals from MTRM. The amplified RF signals

are then sent to MFEM through the backplane. The alarm circuit monitors the status of power amplifier and generates

over-temperature alarm, over-excited alarm and gain decrease alarm signals when conditions satisfied. The alarm signals will be sent to MMCB, where they will be processed and reported to MTRM.

The output power of MPAU can be adjusted by controlling the RF output signal of MTRM.

II. MMCB

MMCB monitors the operation status of MPAU on the real-time basis, reports the detected alarm, measures the transmit power of MPAU, and accomplishes closed-loop power control for the front end RF channel to ensure a constant gain for the whole analog channel. It can also power off the amplifier as instructed.

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2.3.2 External Interface

MPAM provides the following external interfaces:

l RF interface to MTRM

MPAM is connected with MTRM through RF cable and receives RF output signals from MTRM.

l RF interface to MFEM

MPAM is connected with MFEM through RF cable. It sends RF signals to MFEM, which will be finally transmitted through the feeder system.

l Alarm interface

MPAM module is connected with MBKP through a connector. It sends alarm signals through the RS485 serial bus on MBKP to MTRM for processing.

l Power supply interface

It supplies power to the module through MBKP.

System Description

Chapter 2 Hardware Architecture

2.3.3 Key Index

l Supported band: 450MHz band and 800MHz band l Average output power: ¦ 40W (for 450MHz band)

¦ 28W (for 800MHz band)

l Power supply: +26V~+28V DC l Power consumption: 230W l Module size: L % W % T= 430mm % 250mm % 70mm (excluding heat tube

radiator)

2.4 MFEM

2.4.1 Structure and Principle

Micro-bts Radio Frequency Front End Module (MFEM) consists of Micro-bts Divide and Duplexer Receive Filter Unit (MRDU) and Micro-bts Low-Noise Amplifier (MLNA).

The functional structure is shown in Figure 2-5.

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MLNA MRDU

RXD-OUT

RXD-Test

System Description

Chapter 2 Hardware Architecture

RXD-ANT

RXM-OUT RXM-Test

-IN

TX-Test

TX/RXM-ANT

Figure 2-5 Structure of MFEM

I. MRDU

MRDU contains a duplexer and a diversity receive filter.

l Duplexer

The duplexer is used to isolate transmit signals and receive signals, suppress transmission spurious and reduce antenna quantity.

l Diversity receiving filter

Signals received from the diversity antenna are filtered first by the diversity receiving filter in MRDU, then sent to MLNA for low-noise amplification.

II. MLNA unit

This unit contains 2 independent low-noise amplifiers and a MLNA status detection unit.

l Low-noise amplifier

It performs low-noise amplification for main and diversity signals.

l MLNA status detection unit

The status monitoring circuit monitors the working voltage and current of MLNA, and triggers an alarm when fault is detected.

2.4.2 External Interface

MFEM is connected with the feeder and other modules through RF cables. It provides the following external interfaces: 　

l Interface to MPAM

On the transmit channel, MFEM receives RF signals amplified by MPAM, sends them through the duplexer of MRDU to the antenna system for transmission.

l Interface to MTRM

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On the receive channel, MFEM receives main/diversity RF signals from the antenna system, and after low-noise amplification by MLNA, sends them to MTRM for processing.

l Interface to the antenna system l RF signal monitoring port

On the RF signal monitoring ports, the transmit signal is coupled and output by MRDU, while the main/diversity receive signal is coupled and output by MLNA.

l Power supply interface

It supplies power to the module through MBKP.

2.4.3 Key Index

l Supported band: 450MHz band and 800MHz band l Power supply: 20V~32V DC　 l Power consumption: 11W　 l Dimensions: L % W % T = 430mm % 250mm % 60mm 　

System Description

Chapter 2 Hardware Architecture

2.5 MAPM

2.5.1 Structure and Principle

The functional structure of MAPM is shown in Figure 2-6. MAPM consists of AC/DC converter, power monitor & control unit, and battery management unit.

~220VAC

AC/DC power converter

Battery management

Power monitor &

control unit

unit

+27VDC

RS485

4 dry nodes

Battery interface

Figure 2-6 Structure of MAPM module

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The AC/DC conversion unit converts Ã220V AC power (mains) into +27V DC power. The power monitor & control unit performs status detection and alarm reporting. The battery management unit performs energy charging and discharging for batteries.

2.5.2 External Interface

The external interfaces of MAPM are shown in Figure 2-6.

l AC input interface

Local mains are input through this interface.

l DC output interface

This interface is connected with the MBKP through which it supplies 27V DC power to other modules.

l Battery interface

The external batteries can be connected with the MAPM through this interface so as to supply power to the ODU3601C in the case of AC power failure.

System Description

Chapter 2 Hardware Architecture

l Alarm interface

MPAM is connected with MBKP through a connector. It sends alarm signals through the RS485 serial bus on MBKP to MTRM for processing.

l Dry nodes

One of the four dry nodes is used to detect failure alarms of the AC lightning arrester, while the other three are used to monitor the Uninterrupted Power Supply (UPS).

2.5.3 Key Index

l Phases of AC input: Single phase l Rated voltage of AC input: 220V AC l Fluctuation range of AC input voltage: 150~300V AC l Overvoltage protection point of AC input: 310V AC　 l Undervoltage protection point of AC input: 140V AC　 l Dimensions: L % W % T = 430mm % 250mm % 90mm　

2.6 MBKP

The backplane ODU3601C is the same as that of BTS3601C. The only difference is that the slot 1 is not configured (with MBPM) when used for ODU3601C.

ODU3601C consists of four modules: MAPM, MTRM, MFEM, and MPAM. MBKP is used to connect these four modules.

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The power supply module supplies +27V DC power to other functional modules through the MBKP.

The alarm signals of MPAM and MAPM are sent to MTRM through the RS485 bus on MBKP. MTRM then transmits the signals through the optical fiber to the upper-level BTS. The OMU of upper-level BTS processes these signals and sends them through OML to BSC.

2.7 Antenna and Feeder Subsystem

The clock synchronization signal of ODU3601C is provided by the upper -level BTS through the optical fiber. So the antenna and feeder system of ODU3601C only has RF antenna and has no dual-satellite synchronization antenna.

The antenna and feeder subsystem transmits the modulated RF signals and receives the signals from MS.

RF antenna & feeder is composed of the antenna, jumper from antenna to feeder, feeder, and the jumper from feeder to cabinet-top, as shown in Figure 2-7.

System Description

Chapter 2 Hardware Architecture

RF antenna

Jumper

Feeder

ODU3601C

Jumper

Figure 2-7 Structure of RF antenna & feeder

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Note:

If the distance from the antenna to the ODU3601C cabinet is within 15 meters, jumpers can be used directly to connect the antenna and the cabinet. Detailed installation procedures are described in the

Installation Manual.

I. Antenna

Antenna is the end point of transmitting and start point of receiving. Antenna type, gain, coverage pattern and front-to-rear ratio may affect the system performance. The network designer should choose antenna properly based on the subscriber number and system coverage.

1) Antenna gain Antenna gain is the capability of the antenna to radiate the input power in specific

directions. Normally, the higher gain, the larger coverage. But there may be blind area in the vicinity.

System Description

Chapter 2 Hardware Architecture

2) Antenna pattern Antenna pattern describes the radiation intensity of the antenna in all directions. In

the field of telecommunication, it usually means a horizontal pattern. BTS antenna is available in two types: omni antenna and directional antenna. The directional antenna includes the following types: 120â, 90â , 65â and 33â.

3) Polarization Polarization is used to describe the direction of the electrical field. The mobile

communication system often uses uni-polarization antennas. Bi-polarization antennae, with the two polarization directions perpendicular to each other, have been used recently to reduce the quantity of antennae.　

4) Diversity technology Electrical wave propagation in urban area has the following features:

l Field intensity value changes slowly with places and times. It changes in the rule

of logarithmic normal distribution, which is called slow attenuation.

l Field intensity transient value attenuates selectively due to multi-path

transmission. The attenuation rules falls in Rayleigh distribution, which is called fast attenuation.

Either fast attenuation or slow attenuation impairs the quality of communication or even interrupts the call. Diversity technology is one of the most effective technologies to tackle the problem. Diversity receiving and combining tec hnology can be used to minimize the attenuation when there is little correlation between the two attenuated signals.

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There are two types of diversity technologies: polarized diversity and space diversity. In the present mobile communication system, horizontal space diversity and polarized

diversity are both supported. Theoretical conclusion shows that space diversity is effective when the distance between two antennae is over 10 wavelengths.

Polarized diversity facilitates antenna installation and saves space, therefore it is used more and more extensively.

5) Antenna isolation The receiving/transmitting antenna must be installed with sufficient isolation to

minimize the effect on the receiver. The isolation space is subject to the out-band noise of the transmitter and the sensitivity of the receiver.　

II. Feeder

Normally, the standard 7/8 inch or 5/4 inch feeders are used to connect the outdoor antenna and indoor cabinet. In the site installation, 7/16 DIN connectors should be prepared based on the actual length of feeders.

System Description

Chapter 2 Hardware Architecture

Three grounding cable clips for lightning protection should be applied at the tower top (or building roof), feeder middle, and the wall hole through which feeder is led indoor. If the feeder is excessively long, additional cable clips are needed.

Since 7/8 inch feeder should not be bent, the tower top (or building roof) antenna and the feeder, indoor cabinet and the feeder should be connected via jumpers. The jumpers provided by Huawei are 1/2 inch, 3.5m long, and with 7/16DIN connectors.

At the 450MHz band, the loss is about 2.65dB every 100m for 7/8 inch feeder, and about 1.87dB every 100m for 5/4 inch feeder.

At the 800MHz band, the loss is about 3.9dB every 100m for 7/8 inch feeder, and about 2.8dB every 100m for 5/4 inch feeder.

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