BTS3900A GSM Technical Description-(V300R008_07)

BTS3900A GSMV300R008

Technical Description

Issue 07Date 2009-06-20

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Contents

About This Document.....................................................................................................................11 Changes in BTS3900A GSM Technical Description...........................................................1-12 Components of the BTS3900A.................................................................................................2-13 Logical Structure of the BTS3900A.........................................................................................3-14 Monitoring System of the BTS3900A ....................................................................................4-15 Reference Clocks of the BTS3900/BTS3900A........................................................................5-16 Signal Flow of the BTS3900/BTS3900A.................................................................................6-17 Topologies of the BTS...............................................................................................................7-18 Surge Protection Specifications of the BTS3900A...............................................................8-19 Configuration of the BTS3900/BTS3900A.............................................................................9-1

9.1 BTS3900/BTS3900A Configuration Principles..............................................................................................9-29.2 RF Cable Connections of the DRFUs.............................................................................................................9-89.3 RF Cable Connections of the GRFUs...........................................................................................................9-199.4 RF Cable Connections for the Coexistence of the DRFUs and GRFUs.......................................................9-229.5 CPRI Cable Connections of the RFUs..........................................................................................................9-259.6 Typical Configuration of the BTS3900/BTS3900A.....................................................................................9-27

BTS3900A GSMTechnical Description Contents

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Figures

Figure 2-1 BTS3900A..........................................................................................................................................2-2Figure 3-1 Logical structure of the BTS3900A....................................................................................................3-1Figure 4-1 Monitoring ports on the BBU.............................................................................................................4-1Figure 4-2 Components of the monitoring system...............................................................................................4-2Figure 6-1 DL traffic signal flow.........................................................................................................................6-1Figure 6-2 UL traffic signal flow.........................................................................................................................6-2Figure 6-3 Signaling flow.....................................................................................................................................6-3Figure 6-4 DL traffic signal flow.........................................................................................................................6-4Figure 6-5 UL traffic signal flow.........................................................................................................................6-5Figure 6-6 Signaling flow.....................................................................................................................................6-6Figure 6-7 DL traffic signal flow.........................................................................................................................6-7Figure 6-8 UL traffic signal flow.........................................................................................................................6-8Figure 6-9 Signaling flow.....................................................................................................................................6-9Figure 7-1 Star topology.......................................................................................................................................7-1Figure 7-2 Chain topology...................................................................................................................................7-2Figure 7-3 Tree topology......................................................................................................................................7-2Figure 7-4 Ring topology.....................................................................................................................................7-2Figure 7-5 Regrouping for disconnection in the ring topology............................................................................7-4Figure 7-6 Layer-2 networking topology.............................................................................................................7-4Figure 7-7 Layer-3 networking topology.............................................................................................................7-5Figure 7-8 Star topology.......................................................................................................................................7-5Figure 7-9 Chain topology...................................................................................................................................7-5Figure 7-10 Ring topology...................................................................................................................................7-6Figure 9-1 BBU slots............................................................................................................................................9-7Figure 9-2 Mapping between the RF cables and their colors...............................................................................9-8Figure 9-3 RF cable connections of S1 (Transmit Independency or Combining/transmit diversity)/S2 (TransmitIndependency or Combining)..............................................................................................................................9-10Figure 9-4 RF cable connections of the DRFU with Transmit Independency or Combining............................9-11Figure 9-5 RF cable connections of S2 (PBT)/S3 (Transmit Independency or Combining)/S4 (TransmitIndependency or Combining)..............................................................................................................................9-13Figure 9-6 RF cable connections of S3/3 configured with three DRFUs...........................................................9-14Figure 9-7 RF cable connections of S2 with 4-way RX diversity......................................................................9-15Figure 9-8 RF cable connections of S2 (transmit diversity)/S4 (transmit independency).................................9-16

BTS3900A GSMTechnical Description Figures


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Figure 9-9 RF cable connections of S5 (Transmit Independency or Combining)/S6 (Transmit Independency orCombining)..........................................................................................................................................................9-18Figure 9-10 RF cable connections of S7 (Transmit Independency or Combining)/S8 (Transmit Independency orCombining)..........................................................................................................................................................9-19Figure 9-11 Mapping between the RF signal cables and their colors................................................................9-19Figure 9-12 RF cable connections (1)................................................................................................................9-20Figure 9-13 RF cable connections (2)................................................................................................................9-21Figure 9-14 RF cable connections (3)................................................................................................................9-22Figure 9-15 Mapping between the RF cables and their colors...........................................................................9-22Figure 9-16 RF cable connections (1)................................................................................................................9-23Figure 9-17 RF cable connections (2)................................................................................................................9-24Figure 9-18 RF cable connections (3)................................................................................................................9-25Figure 9-19 Typical topology of the DRFUs.....................................................................................................9-26Figure 9-20 Typical topology of the GRFUs.....................................................................................................9-26

FiguresBTS3900A GSM


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Tables

Table 4-1 Relationship between the monitoring modules or boards and the buses..............................................4-2Table 4-2 Functions of the monitoring system.....................................................................................................4-3Table 7-1 Comparison of topologies....................................................................................................................7-3Table 8-1 Surge protection specifications of the BTS3900A...............................................................................8-1Table 9-1 RF configuration principles of the BTS3900.......................................................................................9-3Table 9-2 Board configuration principles of the BBU.........................................................................................9-8Table 9-3 Configuration description (1)...............................................................................................................9-9Table 9-4 Configuration description (2).............................................................................................................9-12Table 9-5 Configuration description (3).............................................................................................................9-13Table 9-6 Configuration description (4).............................................................................................................9-15Table 9-7 Configuration description (5).............................................................................................................9-17Table 9-8 Configuration description (6).............................................................................................................9-18Table 9-9 Typical configurations of the antenna mode......................................................................................9-20Table 9-10 Two typical topologies.....................................................................................................................9-27Table 9-11 Typical configurations of the BTS3900A........................................................................................9-27

BTS3900A GSMTechnical Description Tables


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About This Document

PurposeThis document describes the BTS3900A GSM in terms of its components, software andhardware structure, logical structure, configuration types, signal flow, clock synchronizationmodes, and topologies.

Product VersionThe following table lists the product version related to this document.

Product Name Product VersionBTS3900A GSM (hereinafter referred to asBTS3900A)

V300R008

Intended AudienceThis document is intended for:l Network plannersl Field engineersl System engineers

Organization1 Changes in BTS3900A GSM Technical DescriptionThis describes the changes in BTS3900A GSM Technical Description.2 Components of the BTS3900AThe BTS3900A consists of the BBU3900, RFUs, power cabinet, and RF cabinet. The BBU3900is installed in the power cabinet, and the RFUs are installed in the RF cabinet.3 Logical Structure of the BTS3900AThe BTS3900A mainly consists of the BBU and RFUs. The logical structure of the BTS3900Aconsists of the RF subsystem, control subsystem, power subsystem, and antenna subsystem.4 Monitoring System of the BTS3900A

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The monitoring system of the BTS3900A implements power monitoring, fan monitoring, andenvironment monitoring.5 Reference Clocks of the BTS3900/BTS3900AThe BTS3900/BTS3900A supports four types of reference clocks: IP clock, line clock, free-runclock, and external clock.6 Signal Flow of the BTS3900/BTS3900AThe signal flow of the BTS3900/BTS3900A consists of the traffic signal flow and the signalingflow of the BTS. The BTS3900/BTS3900A signal flow is classified into the DL traffic signalflow, UL traffic signal flow, and signaling flow. The BTS3900/BTS3900A supports three typesof transmission mode: TDM, HDLC, and IP. The following sections describe the signal flow ofthe BTS3900/BTS3900A in three transmission modes respectively.7 Topologies of the BTSThe topologies of the BTS include the TDM networking, IP networking, and HDLC networking.Multiple topologies, such as star, chain, tree, and ring, are supported between the BBU3900 andthe RFUs. In practice, these topologies can be combined. Optimum utilization of the topologiescan improve the quality of service and lower the investment on the transmission equipment.8 Surge Protection Specifications of the BTS3900AThis describes the surge protection specifications of the BTS3900A. The surge protectionspecifications of the BTS3900A ports consist of the DC or AC power supply, antenna, signal,and dry contact alarms.9 Configuration of the BTS3900/BTS3900AThis describes the configuration principles of the BTS3900/BTS3900A, RF cable connections,CPRI cable connections, and typical configurations of the RFUs.

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

Symbol DescriptionIndicates a hazard with a high level of risk, which if notavoided, will result in death or serious injury.

Indicates a hazard with a medium or low level of risk, whichif not avoided, could result in minor or moderate injury.

Indicates a potentially hazardous situation, which if notavoided, could result in equipment damage, data loss,performance degradation, or unexpected results.Indicates a tip that may help you solve a problem or savetime.Provides additional information to emphasize or supplementimportant points of the main text.

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

Convention DescriptionTimes New Roman Normal paragraphs are in Times New Roman.Boldface Names of files, directories, folders, and users are in

boldface. For example, log in as user root.Italic Book titles are in italics.Courier New Examples of information displayed on the screen are in

Courier New.

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

Convention DescriptionBoldface The keywords of a command line are in boldface.Italic Command arguments are in italics.[ ] Items (keywords or arguments) in brackets [ ] are optional.{ x | y | ... } Optional items are grouped in braces and separated by

vertical bars. One item is selected.[ x | y | ... ] Optional items are grouped in brackets and separated by

vertical bars. One item is selected or no item is selected.{ x | y | ... }* Optional items are grouped in braces and separated by

vertical bars. A minimum of one item or a maximum of allitems can be selected.

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

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

Convention DescriptionBoldface Buttons, menus, parameters, tabs, window, and dialog titles

are in boldface. For example, click OK.

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Convention Description> Multi-level menus are in boldface and separated by the ">"

signs. For example, choose File > Create > Folder .

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

Format DescriptionKey Press the key. For example, press Enter and press Tab.Key 1+Key 2 Press the keys concurrently. For example, pressing Ctrl+Alt

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

the two keys should be pressed in turn.

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

Action DescriptionClick Select and release the primary mouse button without moving

the pointer.Double-click Press the primary mouse button twice continuously and

quickly without moving the pointer.Drag Press and hold the primary mouse button and move the

pointer to a certain position.

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1 Changes in BTS3900A GSM TechnicalDescription

This describes the changes in BTS3900A GSM Technical Description.

07(2009-06-20)This is the sixth commercial release.Based on V300R008 06 (2009-04-20), the changes are as follows:The document name changes from BTS3900A GSM Product Description to BTS3900A GSMTechnical Description.Based on V300R008 06 (2009-04-20), no part is added, and the following information is deleted:l Introduction to the BTS3900A.l Power Distribution Modes of the BTS3900A.l Technical Specifications of the BTS3900A.

06(2009-04-20)This is the fifth commercial release.Based on V300R008 05 (2009-02-16), the changes are as follows:The description of IP/HDLC is added.

05(2009-02-16)This is the fourth commercial release.Based on V300R008 04 (2008-11-20), the changes are as follows:The name of antenna mode is changed.

04(2008-11-20)This is the third commercial release.Based on V300R008 03 (2008-07-15), new content and the changes are as follows:

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l The GRFU RF connection is added.l The description of configuration principles for the BTS3900A is modified.l The description of receiver specifications and Output Power is modified.l The description of values of power consumption is modified.l The description of the functions of the GRFU is modified.

03(2008-07-15)This is the second commercial release.Based on V300R008 02 (2008-04-30), no part is added or deleted, and the changes are as follows:l The description of BTS3900A monitoring system is modified.l The description of configuration principles for the BTS3900A is modified.l The figure of the DRFU RF connection is optimized.l The description of values of power consumption is modified.

02(2008-04-30)This is the initial commercial release.Based on V300R008 01 (2008-03-08), new content is as follows:l The description of configuration principles for the BTS3900A is added.

Based on V300R008 01 (2008-03-08), no part is deleted, and the following contents aremodified:l The description of the logical structure of the BTS3900A is optimized.l The description of the power distribution modes of the BTS3900A is optimized.l The description of the monitoring system of the BTS3900A is modified.l The description of the signal flow of the BTS3900/BTS3900A is modified.l The description of RF configuration principles for the BTS3900A is optimized.l In the description of RF cable connections of the DRFU, the figure of S2 (transmit

diversity), S4 (transmit independency), and the image of S2 (four-way receive diversity)are modified.

l The description of BTS OM functions is optimized.l The description of the ring networking is optimized.l The description of receiver specifications is modified.l The description of values of power consumption is modified.l The description of compliance standards for the BTS3900/BTS3900A is modified.

01(2008-03-08)This is the initial draft release.

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2 Components of the BTS3900AThe BTS3900A consists of the BBU3900, RFUs, power cabinet, and RF cabinet. The BBU3900is installed in the power cabinet, and the RFUs are installed in the RF cabinet.Figure 2-1 shows the BTS3900A.

BTS3900A GSMTechnical Description 2 Components of the BTS3900A


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Figure 2-1 BTS3900A

The function modules of the BTS3900A are described as follows:l The BBU3900 is a baseband processing unit that enables interaction between the BTS and

the BSC.l The RFU performs modulation, demodulation, data processing, and combining and

dividing for baseband signals and RF signals. The RFU can be a DRFU or a GRFU. TheDRFU supports two carriers while the GRFU supports more than two carriers.

l The power cabinet houses the BBU3900 and the RF cabinet houses the RFUs. In addition,the power cabinet and the RF cabinet provide functions such as power distribution, heatdissipation, and surge protection. The power cabinet has two types: APM30 and APM30H.The APM30H can be configured in the areas of poor air quality.

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3 Logical Structure of the BTS3900AThe BTS3900A mainly consists of the BBU and RFUs. The logical structure of the BTS3900Aconsists of the RF subsystem, control subsystem, power subsystem, and antenna subsystem.Figure 3-1 shows the logical structure of the BTS3900A.

Figure 3-1 Logical structure of the BTS3900A

The logical subsystems of the BTS3900A are described as follows:l RF subsystem, implemented by the RFUs

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l Control subsystem: implemented by the BBUl Power subsystem, implemented by the following modules:

PDU Power subrack (AC/DC) DCDU-02 DCDU-03 Battery

l Antenna subsystem, implemented by the following modules: Antenna Bias-Tee GATM TMA

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4 Monitoring System of the BTS3900AThe monitoring system of the BTS3900A implements power monitoring, fan monitoring, andenvironment monitoring.

Monitoring Ports on the BBUFigure 4-1 shows the monitoring ports on the BBU.

Figure 4-1 Monitoring ports on the BBU

l The BBU can provide a maximum of 2 RS485 buses and 16 Boolean signal inputs.l The modules connected to RS485 bus 0 cannot be connected to RS485 bus 1and the

modules connected to RS485 bus 1 cannot be connected to RS485 bus 0.l If two PMUs are configured and the settings of their DIP switches are the same, the two

PMUs cannot be connected to the same bus.

Components of the Monitoring SystemFigure 4-2 shows the components of the monitoring system.

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Figure 4-2 Components of the monitoring system

NOTE

RS485 bus 0 is indicated by bus0. RS485 bus 1 is indicated by bus1.

Table 4-1 describes the relationship between the monitoring modules or boards and the buses.

Table 4-1 Relationship between the monitoring modules or boards and the busesModule or Board BusFMUA (mandatory) bus0GATM2 (optional) bus0PMU (mandatory) bus1AFMU (mandatory) bus1GATM1 (optional) bus1EMUA (optional) bus1

Functions of the Monitoring SystemTable 4-2 describes the functions of the monitoring system.

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Table 4-2 Functions of the monitoring systemModule or Board FunctionFAN l Detects fan faults.

l Adjusts the fan speed.l Detects the fan speed and temperature of

the fans.GATM Reports alarms related to RET control

signals.EMUA l Communicates with the BBU through the

RS485 port, through which two RS485signals are transmitted.

l Detects the input voltage.l Provides ports for connections to the

humidity and temperature sensor of 12 VDC/24 V DC current type.

l Provides ports for detecting the inputBoolean signals of dry contact type and ofOC type.

l Provides ports for six external Booleanoutputs of relay node type.

PMU l Communicates with the BBU through theRS232/RS422 serial port.

l Manages the power system and batterycharging and discharging.

l Reports the detection results about waterdamage, smoke, door status, andcustomized Boolean values and alsoreports the ambient humidity andtemperature, battery temperature, andcustomized analog values.

l Detects power distribution and reportsrelated alarms.

DCDU Monitors the operating status of surgeprotection.

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Module or Board FunctionFMUA l Collects the alarm information about the

intra-cabinet environment on thetemperature, humidity, smoke, waterdamage, and door status.

l Collects the alarm information about thesurge protection of the DCDU-02.

l Monitors the operating status of fans andadjusts the fan speed based on thetemperature or under the control of theBBU.

l Stops the rotation of the fans when theambient temperature is low.

l Detects the temperature and reports relatedalarms.

l Supports the cascading and extension ofRS485 ports.

l Supports the cascading of FMUAs.

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5 Reference Clocks of the BTS3900/BTS3900AThe BTS3900/BTS3900A supports four types of reference clocks: IP clock, line clock, free-runclock, and external clock.

IP ClockThe IP clock acts as the clock source of the BTS3900/BTS3900A when the BTS uses the IP overFE transmission mode. The IP clock requires the configuration of the IP clock server in thenetwork. The IP clock server carries the reference clock information in the UDP data packet,and then transmits the clock packets to the BTS. The BTS then resolves the clocks signals fromthe clock packet and uses these signals as reference clock source.

Line ClockThe BBU3900 directly extracts the clock from the E1/T1 interface. Then, the BBU exports theprecise 2 MHz and 8 kHz clocks after frequency dividing, phase locking, and phase adjusting.The 2 MHz and 8 kHz clocks are used for bit synchronization and frame synchronization in theBTS. The line clock consists of the trace BSC clock and trace transmission clock. The BTSextracts the clock signals from the BSC through the E1/T1 interface and uses them as thereference clock source. When the transmission mode of the BTS is upgraded from E1/T1 modeto IP mode, if there is no IP clock, the BTS extracts the clock signals from the transmissionnetwork through the E1/T1 interface and use them as the reference clock source.

Free-Run ClockIn the absence of external clocks, the internal free-run clock ensures that the BTS keeps workingproperly for at least seven days.

External ClockIf the BBU3900 is configured with the USCU, the USCU can receive the external clock signalsfor the GTMU. The USCU supports clock signals including the GPS clock signal, RGPS clocksignal, and BITS clock signal.

BTS3900A GSMTechnical Description 5 Reference Clocks of the BTS3900/BTS3900A


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6 Signal Flow of the BTS3900/BTS3900AThe signal flow of the BTS3900/BTS3900A consists of the traffic signal flow and the signalingflow of the BTS. The BTS3900/BTS3900A signal flow is classified into the DL traffic signalflow, UL traffic signal flow, and signaling flow. The BTS3900/BTS3900A supports three typesof transmission mode: TDM, HDLC, and IP. The following sections describe the signal flow ofthe BTS3900/BTS3900A in three transmission modes respectively.

TDM TransmissionDL Traffic Signal FlowThe DL traffic signal flow is transmitted from the BSC to the MS through the BTS3900/BTS3900A. In the BTS3900/BTS3900A, the BBU and RFUs work together to process the DLtraffic signals. Figure 6-1 shows the DL traffic signal flow of the BTS3900/BTS3900A.

Figure 6-1 DL traffic signal flow

The DL traffic signal flow is as follows:1. The E1 signals from the BSC are transmitted to the BBU through the E1 cable.2. After receiving the E1 signals, the BBU processes the E1 signals as follows:

(1) Extracts clock signals from the E1 signals

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(2) Configures the BTS system based on the data configuration on the OML(3) Encapsulates the E1 data in the format of the CPRI frame, and then transmits the data

to the RFU through the CPRI signal cable3. After receiving the signals, the RFU processes the signals as follows:

(1) Decapsulates the high-speed CPRI frames to obtain the baseband signals(2) Transmits the baseband signals to the relevant operation units for encryption and

interleaving(3) Converts the digital signals into the analog signals and modulates the analog signals

into RF signals(4) Combines or divides the RF signals based on its own configuration(5) Transmits the combined or divided signals through the feeder and antenna

UL Traffic Signal FlowOpposite to the DL traffic signal flow, the UL traffic signal flow is transmitted from the MS tothe BSC through the BTS3900/BTS3900A. In the BTS3900/BTS3900A, the BBU and RFUswork together to process the UL traffic signals. Figure 6-2 shows the UL traffic signal flow.

Figure 6-2 UL traffic signal flow

The UL traffic signal flow is as follows:1. The antenna receives the signals sent from the MS. If the TMA is configured, the received

signals are amplified by the TMA and then transmitted to the RFU through the feeder.2. After receiving the UL signals, the RFU processes the signals as follows:

(1) Divides the UL signals from the antenna or diversity RX port(2) Converts the divided analog signals into the digital signals to obtain the baseband

signals(3) Transmits the baseband signals to the relevant operation units for decryption and de-

interleaving(4) Encapsulates the processed data in the format of the CPRI frame, and then transmits

the data to the BBU through the CPRI signal cable3. After receiving the signals, the BBU processes the signals as follows:

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(1) Decapsulates the high-speed CPRI frames to obtain the baseband signals(2) Encapsulates the baseband signals in the format of the E1 frame, and then transmits

the signals to the BSC through the E1 cableSignaling FlowThe BTS3900/BTS3900A signaling flow refers to the signaling on the Abis interface. The BBUserves as the control unit and works with the RFUs to process the signaling. Figure 6-3 showsthe signaling flow.

Figure 6-3 Signaling flow

The signaling flow is as follows:1. The signaling data received from the BSC is transmitted to the BBU through the Abis

interface.2. The BBU encapsulates the signaling data in the format of the CPRI frame, and then

transmits the signaling data to the RFU through the CPRI signal cable.3. The RFU decapsulates the CPRI signals into the baseband signals, and then transmits the

baseband signals to the relevant operation units for processing.4. The RFU encapsulates the data of its own status in the format of the CPRI frame, and then

transmits the data to the BBU through the CPRI signal cable.5. The BBU decapsulates the received CPRI signals to obtain the baseband signals.6. The BBU analyzes and processes the baseband signals to obtain the BTS status, and then

sends the status data to the BSC on the Abis interface.

HDLC TransmissionDL Traffic Signal FlowThe DL traffic signal flow is transmitted from the BSC to the MS through the BTS3900/BTS3900A. In the BTS3900/BTS3900A, the BBU and RFUs work together to process the DLtraffic signals. Figure 6-4 shows the DL traffic signal flow of the BTS3900/BTS3900A.



6-3


The DL traffic signal flow is as follows:1. The BSC encapsulates the service data in the format of the HDLC data packet, and then

transmits the data to the BBU through the E1 cable.2. After receiving the E1 signals, the BBU processes the E1 signals as follows:

(1) Extracts the clock signals from the E1 signal(2) Resolves the data packet in the HDLC format from the E1 timeslot signals bound to

the HDLC channel, and then configures the BTS system based on the ESL and OMLdata resolved from the data packet

(3) Encapsulates the HDLC service data in the format of the CPRI frame, and thentransmits the data to the RFU through the CPRI signal cable

3. After receiving the signals, the RFU processes the signals as follows:(1) Decapsulates the high-speed CPRI frames and HDLC packets to obtain the baseband

signals(2) Transmits the baseband signals to the relevant operation units for encryption and







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interleaving(4) Encapsulates the processed signal in the format of the CPRI frame, and then transmits

the signal to the BBU through the CPRI signal cable3. After receiving the signals, the BBU processes the signals as follows:

(1) Decapsulates the high-speed CPRI frames to obtain the data in the format of the HDLCframe

(2) Finds the HDLC transmission channel corresponding to this HDLC data packet, andthen transmits the data in the format of the E1 frame to the BSC through the E1 cable

Signaling FlowThe BTS3900/BTS3900A signaling flow refers to the signaling on the Abis interface. The BBUserves as the control unit and works with the RFUs to process the signaling. Figure 6-6 showsthe signal flow of signaling processing.



6-5


The signaling flow is as follows:1. The BBU receives the signaling data from the BSC through the E1 cable.2. The BBU receives the relevant signaling data and processes the signaling data as required.3. The BBU encapsulates the signaling data to be processed by the RFU in the format of the

CPRI frame, and then transmits the signaling data to the RFU through the CPRI signalcable.

4. The RFU decapsulates the received CPRI signals and processes the signals as required.5. The RFU encapsulates the data of its own status in the format of the CPRI frame, and then

transmits the data to the BBU through the CPRI signal cable.6. The BBU decapsulates the received CPRI signals to obtain the data of the RFU status.7. The BBU analyzes and processes the baseband signals to obtain the BTS status, and then

sends the status data to the BSC on the Abis interface.

IP TransmissionDL Traffic Signal FlowThe DL traffic signal flow is transmitted from the BSC to the MS through the BTS3900/BTS3900A. In the BTS3900/BTS3900A, the BBU and RFUs work together to process the DLtraffic signals. Figure 6-7 shows the DL traffic signal flow of the BTS3900/BTS3900A.




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The DL traffic signal flow is as follows:1. The BSC encapsulates the service data in the UDP payload, and then transmits the IP packet

to the BBU through FE transmission.2. After receiving the IP packet, the BBU processes the packet as follows:

(1) If the current clock mode is configured to the IP clock, the clock packet is identifiedfrom the IP packet. The clock information is resolved from the clock packet for clocksynchronization.

(2) Identifies the packet on the ESL and OML and configures the BTS system based onthe resolved data.

(3) Identifies the service packet and deletes the UDP/IP header of the service packet.Encapsulates the service data in HDLC format and transmits the data to the RFU inthe format of the CPRI frame.

3. After receiving the signals, the RFU processes the signals as follows:(1) Decapsulates the high-speed CPRI frames and HDLC packets to obtain the baseband

signals(2) Transmits the baseband signals to the relevant operation units for encryption and






6-7






interleaving(4) Encapsulates the processed signal in the format of the HDLC frame and then in the

format of the CPRI frame, and then transmits the signal to the BBU through the CPRIsignal cable

3. After receiving the signals, the BBU processes the signals as follows:(1) Decapsulates the high-speed CPRI frames to obtain the data in the format of the HDLC

frame(2) Obtains the UDP/IP header information corresponding to the HDLC data packet in

the configuration data, and then encapsulates the HDLC frame payload in the UDP/IP format. Then, the BBU checks the ARP table, finds the destination MAC address,encapsulates the packets in the MAC format, and transmits the packets to the BSCthrough FE transmission.

Signaling FlowThe BTS3900/BTS3900A signaling flow refers to the signaling on the Abis interface. The BBUserves as the control unit and works with the RFUs to process the signaling. Figure 6-9 showsthe signal flow of signaling processing.




Issue 07 (2009-06-20)


The signaling flow is as follows:1. The BBU receives the signaling data encapsulated in the UDP/IP format from the BSC

through FE transmission.2. After decapsulating the signaling data, the BBU receives the relevant signaling data and

processes the data as required.3. The BBU encapsulates the signaling data to be processed by the RFU in the format of the

CPRI frame, and then transmits the signaling data to the RFU through the CPRI signalcable.

4. The RFU decapsulates the received CPRI signals and processes the signals as required.5. The RFU encapsulates the data of its own status in the format of the CPRI frame, and then

transmits the data to the BBU through the CPRI signal cable.6. The BBU decapsulates the received CPRI signals to obtain the data of the RFU status.7. The BBU analyzes and processes the baseband signals to obtain the BTS status, and then

sends the status data encapsulated in the UDP/IP format to the BSC through FEtransmission.



6-9

7 Topologies of the BTSThe topologies of the BTS include the TDM networking, IP networking, and HDLC networking.Multiple topologies, such as star, chain, tree, and ring, are supported between the BBU3900 andthe RFUs. In practice, these topologies can be combined. Optimum utilization of the topologiescan improve the quality of service and lower the investment on the transmission equipment.

TDM NetworkingThe E1/T1 transmission is used between the BSC and the BTS, and the TDM transmission isused on the Abis interface. The TDM networking can be classified into the star topology, chaintopology, tree topology, and ring topology.Figure 7-1 shows the star topology.

Figure 7-1 Star topology

Figure 7-2 shows the chain topology.

BTS3900A GSMTechnical Description 7 Topologies of the BTS


7-1

Figure 7-2 Chain topology

Figure 7-3 shows the tree topology.

Figure 7-3 Tree topology

Figure 7-4 shows the ring topology.

Figure 7-4 Ring topology

Table 7-1 compares the topologies.

7 Topologies of the BTSBTS3900A GSM



Issue 07 (2009-06-20)

Table 7-1 Comparison of topologiesTopology Application Scenario AdvantageStar topology Applies to common areas,

especially densely populatedareas, such as cities.

l Simple networkingl Easy engineering constructionl Convenient maintenancel Flexible capacity expansionl High network reliability

Chain topology Applies to sparsely populatedareas in strip-like terrain, suchas areas along highways andrailway tracks.

Reduces costs in transmissionequipment, construction, andtransmission link lease.

Tree topology Applies to areas wherenetwork structures, sitedistribution, and subscriberdistribution are complicated,for example, an area wherelarge-scale coverage overlapshot spot or small-scalecoverage.

Requires fewer transmission cablescompared with the star topology.

Ring topology Applies to common scenarios.Due to its strong self-healingcapability, the ring topologyis preferred if permitted by therouting.

If there is a breaking point in the ring,the ring breaks into two chains at thebreaking point automatically. In thisway, the BTSs preceding and followingthe breaking point can work normallydespite the breaking point, thusimproving the robustness of the system.For example, BTS0, BTS1, and BTS2are sequentially connected to form a ring(clockwise). When a failure occurs at B,BTS0, the BTS topology preceding B,remains unchanged, and BTS2 andBTS1, the BTSs following B form achain (anticlockwise), as shown inFigure 7-5.



7-3

Figure 7-5 Regrouping for disconnection in the ring topology

IP NetworkingThe FE transmission is used between the BSC and the BTS, and the IP transmission is used onthe Abis interface. The IP networking consists of the layer-2 networking topology and layer-3networking topology.Figure 7-6 shows the layer-2 networking topology.

Figure 7-6 Layer-2 networking topology

Figure 7-7 shows the layer-3 networking topology.




Issue 07 (2009-06-20)

Figure 7-7 Layer-3 networking topology

HDLC NetworkingThe E1/T1 transmission is used between the BSC and the BTS, and the HDLC transmission isused on the Abis interface. The HDLC networking can be classified into the star topology, chaintopology, and ring topology.Figure 7-8 shows the star topology.

Figure 7-8 Star topology

Figure 7-9 shows the chain topology. The upper-level BTS transparently transmits the signalsof the lower-level BTS.

Figure 7-9 Chain topology



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Figure 7-10 shows the ring topology.

Figure 7-10 Ring topology




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8 Surge Protection Specifications of theBTS3900A

This describes the surge protection specifications of the BTS3900A. The surge protectionspecifications of the BTS3900A ports consist of the DC or AC power supply, antenna, signal,and dry contact alarms.

NOTE

The unspecified surge current with maximum discharge current is called nominal discharge current.

Table 8-1 Surge protection specifications of the BTS3900APort Surge Protection Mode Surge CurrentDC power port Differential mode 10 kA (8/20 us surge current)

Common mode 15 kA (8/20 us surge current)AC power port Differential mode 60 kA (8/20 us surge current)

Common mode 60 kA (8/20 us surge current)Antenna port Differential mode 8 kA (8/20 us surge current)

Common mode 40 kA (8/20 us surge current)Dry contact port,RS485 port

Differential mode 250 A (8/20 us surge current)Common mode 250 A (8/20 us surge current)

E1/T1 port Differential mode 3 kA (8/20 us surge current)Common mode 5 kA (8/20 us surge current)

RET antenna Differential mode 3 kA (8/20 us surge current)Common mode 5 kA (8/20 us surge current)

BTS3900A GSMTechnical Description 8 Surge Protection Specifications of the BTS3900A


8-1

9 Configuration of the BTS3900/BTS3900AAbout This Chapter

This describes the configuration principles of the BTS3900/BTS3900A, RF cable connections,CPRI cable connections, and typical configurations of the RFUs.

9.1 BTS3900/BTS3900A Configuration PrinciplesThe BTS3900/BTS3900A is configured with the antenna system, RFUs, and BBU.9.2 RF Cable Connections of the DRFUsOne end of the RF jumper is connected to the RF port on the DRFU, and the other end isconnected to the feeder. You can determine the appropriate RF ports based on the actualnetworking modes.9.3 RF Cable Connections of the GRFUsOne end of the RF jumper is connected to the RF port on the GRFU, and the other end isconnected to the feeder. You can determine the appropriate RF ports based on the actualnetworking modes.9.4 RF Cable Connections for the Coexistence of the DRFUs and GRFUsOne end of the RF jumper is connected to the RF port on the RFU, and the other end is connectedto the feeder. You can determine the appropriate RF ports based on the actual networking modes.9.5 CPRI Cable Connections of the RFUsThe RFUs support two types of topology: star and chain.9.6 Typical Configuration of the BTS3900/BTS3900AThis describes the typical configurations of the BTS3900/BTS3900A.

BTS3900A GSMTechnical Description 9 Configuration of the BTS3900/BTS3900A


9-1

9.1 BTS3900/BTS3900A Configuration PrinciplesThe BTS3900/BTS3900A is configured with the antenna system, RFUs, and BBU.

Basic Configuration Principlesl If multiple hardware configurations meet the requirements for the RNP parameter settings,

the configuration mode that supports smooth upgrades is preferred.l The DRFU is applicable to small- and middle-capacity scenarios; the GRFU is applicable

to large-capacity scenarios. The DRFU and GRFU can be configured in the same cabinetor cell to support flexible capacity expansion.

l Wide coverage is preferred. The DRFU supports the PBT, TX diversity, and 4-way RXdiversity mode. Therefore, the DRFU can be applied to wide-coverage scenarios.

Antenna Configuration Principlesl One dual-polarized antenna can serve a maximum of two RFUs.l By default, RX diversity is adopted on the GSM network. That is, two feeders connected

to two single-polarized antennas or one dual-polarized antenna must be configured in acell.

l Each sector of the BTS must be configured with the minimum number of antennas.l For the 2-way RX diversity, each sector has two antenna channels; for the 4-way RX

diversity, each sector has four antenna channels.

RF Configuration PrinciplesTable 9-1 describes the RF configuration principles of the BTS3900.

9 Configuration of the BTS3900/BTS3900ABTS3900A GSM



Issue 07 (2009-06-20)

Table 9-1 RF configuration principles of the BTS3900Principle Description ExampleConfiguration principles ofthe DRFU ports

l ANT1 and ANT2 are theTX ports of the duplexer.They are connected tojumpers.

l Rx1 in, Rx1 out, Rx2 in,and Rx2 out are the portsfor signals betweeninterconnected DRFUs.When two carriersprovided by a DRFUbelong to the same cell,both Rx1 in and Rx2 in canbe the input ports for RXdiversity of the twocarriers. When twocarriers provided by aDRFU belong to differentcells, Rx1 in is the inputport for RX diversity ofcarrier 1; Rx2 in is theinput port for RX diversityof carrier 2.

l CPRI_0 and CPRI_1 arethe ports for high-speedelectrical cables. TheCPRI_1 port is connectedto the CPRI port on theBBU or to the upper-levelRFU in the case ofcascaded RFUs. TheCPRI_0 port is connectedto the lower-level RFU inthe case of cascadedRFUs.

In S3/3 configuration, threeDRFUs need to beconfigured. The carriersprovided by the middleDRFU belong to differentcells. That is, the Rx1 in porton the middle DRFU is theinput port for RX diversity ofcarrier 1, which belongs tothe first cell. The input portfor RX main of carrier 1 isANT1. The Rx2 in port is theinput port for RX diversity ofcarrier 2, which belongs tothe second cell. The inputport for RX main of carrier 2is ANT2.



9-3

Principle Description ExampleConfiguration principles ofthe GRFU ports

l The ANT_TX/RXA portsupports signal receptionand transmission, and theANT_RXB port supportssignal reception. They areconnected to jumpers.

l RX_INB and RX_OUTAare the ports for signalsbetween interconnectedGRFUs.

l CPRI_0 and CPRI_1 arethe ports for high-speedelectrical cables. TheCPRI_0 port is connectedto the CPRI port on theBBU or to the upper-levelRFU in the case ofcascaded RFUs. TheCPRI_1 port is connectedto the lower-level RFU inthe case of cascadedRFUs.

-

Configuration principles of asingle cabinet

l Star topology is adoptedbetween the BBU andRFUs. The RFUs and thehigh-speed CPRI ports onthe BBU have a one-to-one relationship. That is, ifslot 1 on the RFU is idle,CPRI port 1 on the BBU isalso idle.

l When the DRFU isconfigured, the maximumcell configuration of asingle cabinet is S4/4/4.When the GRFU isconfigured, the maximumcell configuration of asingle cabinet isS12/12/12.

-

Configuration principles ofmultiple cabinets

When star and chaintopology is adopted betweenthe BBU and RFUs, the RFUsupports 3 levels ofcascading in a chain and thusthe BBU supports amaximum of 18 (6 x 3) RFUs.

-




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Principle Description ExampleTwo TRXs of one DRFUconfigured in one sector

l A single DRFU does notsupport the S1/1application; however,three DRFUs support theS3/3 application.

l When the DRFU works inTX PBT, TX diversity, or4-way RX diversity mode,a DRFU provides only oneTRX. Therefore, you canconfigure the DRFU asrequired.

For example, for a site inS5/4/7 cell configuration,nine DRFUs are installed tomeet the requirements ofS6/4/8 cell configuration, butdata configuration is stillperformed on the basis of theS5/4/7 cell configuration.

Number of DRFUs l When the number of TRXsof the site is less than 12,an odd number of TRXscan be configured for acell. Number of DRFUs =round up [(number ofTRXs + number of S1cells) / 2]

l When the number of TRXsof the site is greater than12, an even number ofTRXs should beconfigured for a cell.Number of DRFUs =round up (number ofTRXs after two TRXs areconfigured in one sector /2)

l S3/3/3: Number ofDRFUs = round up (9 / 2)= 5; S1/2/3: Number ofDRFUs = round up [(6 +1) / 2] = 4.

l After two TRXs areconfigured in one sector,the S5/5/5 configuration isS6/6/6. Number of DRFUs= (6 + 6 + 6) / 2 = 9.

Number of GRFUs One GRFU does not servertwo cells. Each cell with asingle antenna can beconfigured with a maximumof two GRFUs.

-

DRFU TRX allocation indouble-antenna-systemmode

After TRX allocation, thecells with an odd number ofTRXs become neighboringcells of each other.l S5 = S3 + S2 or S5 = S2 +

S3l S6 = S4 + S2 or S6 = S3 +

S3l S7 = S4 + S3 or S7 = S3 +

S4l S8 = S4 + S4

l In S3/5/4 configuration,S5 can be divided into S3+ S2. Then, the cellconfiguration becomesS3/(3/2)/4.

l In S2/5/5 configuration,the first S5 is divided intoS2 + S3; the second S5 isdivided into S3 + S2.Then, the cellconfiguration becomesS2/(2/3)/(3/2).



9-5

Principle Description ExampleDRFUs at two bandsconfigured in a site

l If the number of DRFUs isnot more than 6 in adouble-band site, theDRFUs at two bands areconfigured in the samecabinet. If the RF cabinetis configured with lessthan three 900 MHzDRFUs and three 1800MHz DRFUs, the 900MHz DRFUs are installedin of the three slots on theleft of the RF cabinet, andthe 1800 MHz DRFUs areinstalled in the three slotson the right of the RFcabinet.

l When two RF cabinets areconfigured and thenumber of DRFUs at eachband is not more than six,the 900 MHz DRFUs areinstalled in the first RFcabinet and the 1800 MHzDRFUs are installed in thesecond RF cabinet. TheDRFUs are installed in theslots according to thetypical S4/4/4configuration. When twoRF cabinets areconfigured and thenumber of DRFUs at oneband (for example, 900MHz) is greater than six,other DRFUs at this bandshare the other RF cabinetwith the DRFUs at theother band (for example,1800 MHz). The mixedconfiguration of DRFUs attwo bands is not allowed.

-




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Principle Description ExampleCoexistence configurationprinciples of the DRFUs andGRFUs

Coexistence configurationprinciples of the DRFUs andGRFUs are as follows:l The primary BCCH is

carried on a GRFU.l When the requirements of

the output power andnumber of carriers are metand the cell configurationis greater than S4, a singleDRFU is configured withone TRX; when twoDRFUs are configured,one DRFU is preferablyused.

l The TX power of a DRFUand that of a GRFU withina cell are almost the same.The power differenceshould not exceed 0.5 dB.

l When the DRFUs andGRFUs are configured inone cell, 4-way RXdiversity and TX diversityare not supported.

l The DRFUs and GRFUsare not recommended inthe same new site.

-

NOTE

In the mode of configuring two TRXs in one sector, a DRFU belongs to only one sector.

BBU Configuration Principlesl A BBU has 6 CPRI ports and supports a maximum of 72 carriers.l Figure 9-1 shows the BBU slots.

Figure 9-1 BBU slots



9-7

l Table 9-2 describes the board configuration principles of the BBU.

Table 9-2 Board configuration principles of the BBUModule or Board DescriptionUBFA One UBFA must be configured.UPEU l One UPEU must be configured.

l A second UPEU can be configured whenthe backup power is required. The BBU,however, cannot be configured with theUPEU and the UEIU at the same time.

UEIU The UEIU is optional and a maximum ofone UEIU can be configured.

GTMU l One GTMU must be configured.l The GTMU is installed in slot 5 or slot

6.UELP l Not required in the BTS3900

l One UELP must be configured in theBTS3900A. The UELP is installed inslot 1.

USCU l The USCU is optional and a maximumof one USCU can be configured.

l The USCU is installed in slot 0.

9.2 RF Cable Connections of the DRFUsOne end of the RF jumper is connected to the RF port on the DRFU, and the other end isconnected to the feeder. You can determine the appropriate RF ports based on the actualnetworking modes.

RF Cable Connectionsl The TX/RX mode and antenna mode described in the following list are set on the BSC side.l The RF cables differ from each other in colors. Figure 9-2 shows the mapping between the

RF signal cables and their colors.

Figure 9-2 Mapping between the RF cables and their colors




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S1 with Transmit Independency or Combining, S1 with Transmit Diversity, andS2 with Transmit Independency or Combining

The S1 with Transmit Independency or Combining, S1 with transmit diversity, and S2 withTransmit Independency or Combining use the configuration of one DRFU and one dual-polarized antenna. Table 9-3 describes the related configurations.

Table 9-3 Configuration description (1)NetworkingConfiguration

Transmit mode Antenna Mode HardwareConfiguration

S1, TransmitIndependency orCombining

TransmitIndependency orCombining

Double Feeder(2TX + 2RX)

l One DRFUl One dual-

polarized antennaS1, TransmitDiversity

Transmit Diversity Double Feeder(2TX + 2RX)




Figure 9-3 shows cable connections.



9-9

Figure 9-3 RF cable connections of S1 (Transmit Independency or Combining/transmitdiversity)/S2 (Transmit Independency or Combining)

The other available antenna modes for the DRFU with Transmit Independency or Combiningare Single Feeder (1TX + 1RX), Double Feeder (1TX + 1RX), and Double Feeder (1TX +2RX). The transmit mode is Transmit Independency or Combining. Figure 9-4 shows cableconnections.




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Figure 9-4 RF cable connections of the DRFU with Transmit Independency or Combining



9-11

S2 with PBT, S3 with Transmit Independency or Combining, and S4 with TransmitIndependency or Combining

The S2 with PBT, S3 with Transmit Independency or Combining, and S4 with TransmitIndependency or Combining use the configuration of two DRFUs and one dual-polarizedantenna. Table 9-4 describes the related configurations.



S2, PBT PBT Single Feeder (1TX+ 2RX)

l Two DRFUsl One dual-

polarized antennaS3, TransmitIndependency orCombining


Single Feeder (1TX+ 2RX)








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Figure 9-5 RF cable connections of S2 (PBT)/S3 (Transmit Independency or Combining)/S4(Transmit Independency or Combining)

The S3/3 with Transmit Independency or Combining uses three DRFUs and two dual-polarizedantennas. Table 9-5 describes the related configurations.



S3/3, TransmitIndependency orCombining


l DRFU0: SingleFeeder (1TX +2RX)

l DRFU1: DoubleFeeder (2TX +4RX)


l Three DRFUsl Two dual-

polarizedantennas




9-13

Figure 9-6 RF cable connections of S3/3 configured with three DRFUs

S2 with 4-Way RX DiversityThe S2 with 4-way RX diversity uses two DRFUs and two dual-polarized antennas. The typicalconfigurations are as follows:l Set the receive mode to 4-Way Receive Diversity.l Set the antenna mode to Double Feeder (2TX + 4RX).Figure 9-7 shows cable connections.




Issue 07 (2009-06-20)

Figure 9-7 RF cable connections of S2 with 4-way RX diversity

S2 with Transmit Diversity and S4 with Transmit IndependencyThe S2 with transmit diversity and S4 with transmit independency use the configuration of twoDRFUs and two dual-polarized antennas. Table 9-6 describes the related configurations.



S2, TransmitDiversity

Transmit Diversity Double Feeder(2TX + 2RX)

l Two DRFUsl Two dual-

polarizedantennasS4, TransmitIndependency






9-15

Figure 9-8 RF cable connections of S2 (transmit diversity)/S4 (transmit independency)

S5 with Transmit Independency or Combining and S6 with TransmitIndependency or Combining

The S5 with Transmit Independency or Combining and S6 with Transmit Independency orCombining use the configuration of three DRFUs and two dual-polarized antennas. Table 9-7describes the related configurations.




Issue 07 (2009-06-20)








l Three DRFUsl Two dual-

polarizedantennas









9-17

Figure 9-9 RF cable connections of S5 (Transmit Independency or Combining)/S6 (TransmitIndependency or Combining)

S7 with Transmit Independency or Combining and S8 with TransmitIndependency or Combining

The S7 with Transmit Independency or Combining and S8 with Transmit Independency orCombining use the configuration of four DRFUs and two dual-polarized antennas. Table 9-8describes the related configurations.






l Four DRFUsl Two dual-

polarizedantennasS8, Transmit

Independency orCombining






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Figure 9-10 RF cable connections of S7 (Transmit Independency or Combining)/S8 (TransmitIndependency or Combining)

9.3 RF Cable Connections of the GRFUsOne end of the RF jumper is connected to the RF port on the GRFU, and the other end isconnected to the feeder. You can determine the appropriate RF ports based on the actualnetworking modes.

RF Cable ConnectionsThe RF cables differ from each other in colors. Figure 9-11 shows the mapping between the RFsignal cables and their colors.

Figure 9-11 Mapping between the RF signal cables and their colors



9-19

The antenna mode of the GRFU is set on the BSC side. Table 9-9 describes the typicalconfigurations of the antenna mode for the GRFU.

Table 9-9 Typical configurations of the antenna modeGRFU Configuration Antenna ModeSingle module Double Feeder (1TX + 2RX)Two interconnected modules Single Feeder (1TX + 2RX)

The other available antenna modes for the GRFU are Single Feeder (1TX + 1RX) and DoubleFeeder (1TX + 1RX). Figure 9-12 shows cable connections.

Figure 9-12 RF cable connections (1)

Cell Configuration with a Single GRFUWhen a dual-polarized antenna is configured, one TX channel and two RX channels are used.The ANT_RXB and ANT_TX/RXA ports receive the signals from the antenna to achieve RXdiversity.




Issue 07 (2009-06-20)



Cell Configuration with Two GRFUsThe ANT_TX/RXA port on each GRFU supports the receiving and transmitting of signals. TwoGRFUs provide RX signals for each other through the RF interconnection ports. Thus, the RXdiversity is implemented.Figure 9-14 shows cable connections.



9-21


9.4 RF Cable Connections for the Coexistence of the DRFUsand GRFUs

One end of the RF jumper is connected to the RF port on the RFU, and the other end is connectedto the feeder. You can determine the appropriate RF ports based on the actual networking modes.

RF Cable ConnectionsThe RF cables differ from each other in colors. Figure 9-15 shows the mapping between the RFsignal cables and their colors.

Figure 9-15 Mapping between the RF cables and their colors




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Single Antenna System Configured With One DRFU and One GRFUWhen a DRFU and a GRFU share a dual-polarized antenna, the typical configuration of theantenna mode for the DRFU and GRFU is as follows:l The DRFU is configured with Single Feeder (1TX + 2RX).l The GRFU is configured with Single Feeder (1TX + 2RX).Figure 9-16 shows cable connections.


Double Antenna Systems Configured with One DRFU and One GRFUWhen a DRFU and a GRFU share two dual-polarized antennas, the typical configuration of theantenna mode for the DRFU and GRFU is as follows:l The DRFU is configured with Double Feeder (2TX + 2RX).



9-23

l The GRFU is configured with Double Feeder (1TX + 2RX).Figure 9-17 shows cable connections.


Double Antenna Systems Configured with Two DRFUs and One GRFUWhen two DRFUs and a GRFU share two dual-polarized antennas, the typical configuration ofthe antenna mode for the DRFUs and GRFU is as follows:l The DRFUs are configured with Single Feeder (1TX + 2RX).l The GRFU is configured with Double Feeder (1TX + 2RX).Figure 9-18 shows cable connections.




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9.5 CPRI Cable Connections of the RFUsThe RFUs support two types of topology: star and chain.Figure 9-19 shows the typical topology of the DRFUs.



9-25

Figure 9-19 Typical topology of the DRFUs

Figure 9-20 shows the typical topology of the GRFUs.

Figure 9-20 Typical topology of the GRFUs

NOTE

When the chain topology is used, a maximum of three levels of RFUs can be connected to one BBU.




Issue 07 (2009-06-20)

Table 9-10 describes the twotypical topologies.

Table 9-10 Two typical topologiesTopology Application ScenarioStar Supports the minimum configuration

scenariosChain Supports the maximum configuration

scenarios

9.6 Typical Configuration of the BTS3900/BTS3900AThis describes the typical configurations of the BTS3900/BTS3900A.The BTS3900 cabinet supports three types of power input: -48 V DC, +24 V DC, and 220 VAC. The cabinets that support different types of input power are different in structure, mainlyin power distribution unit.Table 9-11 describes the typical configurations of the BTS3900A.

Table 9-11 Typical configurations of the BTS3900ATypical Configuration DescriptionAPM30+RFC Six RFU: 20-minutes backup power (24 Ah).TMC+RFC Provides installation space for user devices. The site has DC

power supply, and no backup power is provided.APM30+RFC+BBC Six RFU: backup power (184 Ah) of 5 hours.APM30+RFC+TMC+BBC

Six RFU: backup power (184 Ah) of 4 hours.NOTE

The power consumption of the transmission cabinet is less than 200 W.

NOTEThe BTS3900A, an outdoor macro base station, is applicable to the outdoor centralized installation scenario.The RFUs are installed in the RF cabinet, and the BBU3900 is installed in the APM30 or transmissioncabinet.



9-27

ContentsFiguresTablesAbout This Document1 Changes in BTS3900A GSM Technical Description2 Components of the BTS3900A3 Logical Structure of the BTS3900A4 Monitoring System of the BTS3900A5 Reference Clocks of the BTS3900/BTS3900A6 Signal Flow of the BTS3900/BTS3900A7 Topologies of the BTS8 Surge Protection Specifications of the BTS3900A9 Configuration of the BTS3900/BTS3900A9.1 BTS3900/BTS3900A Configuration Principles9.2 RF Cable Connections of the DRFUs9.3 RF Cable Connections of the GRFUs9.4 RF Cable Connections for the Coexistence of the DRFUs and GRFUs9.5 CPRI Cable Connections of the RFUs9.6 Typical Configuration of the BTS3900/BTS3900A

BTS3900A GSM Technical Description-(V300R008_07)

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