Huawei Airbridge BTS3612A-1900 User manual

Technical Manual
Airbridge BTS3612A CDMA Base Station System Principle Table of Contents
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Table of Contents
Chapter 1 Overall Structure.......................................................................................................... 1-1
1.1 Physical Structure..............................................................................................................1-1
1.2 Functional Structure...........................................................................................................1-3
Chapter 2 Baseband Subsystem .................................................................................................2-1
2.1 Overview............................................................................................................................2-1
2.1.1 Functional Structure................................................................................................2-1
2.1.2 Introduction to Baseband Boards............................................................................2-1
2.2 BCKM.................................................................................................................................2-2
2.2.1 Overview ................................................................................................................. 2-2
2.2.2 Structure and Principle............................................................................................2-2
2.2.3 External Interfaces .................................................................................................. 2-4
2.2.4 Indices.....................................................................................................................2-5
2.3 BCIM..................................................................................................................................2-5
2.3.1 Overview ................................................................................................................. 2-5
2.3.2 Structure and Principle............................................................................................2-5
2.3.3 External Interfaces .................................................................................................. 2-7
2.3.4 Indices.....................................................................................................................2-7
2.4 BCPM.................................................................................................................................2-7
2.4.1 Overview ................................................................................................................. 2-7
2.4.2 Structure and principle............................................................................................ 2-8
2.4.3 External Interfaces .................................................................................................. 2-9
2.4.4 Indices...................................................................................................................2-10
2.5 BRDM ..............................................................................................................................2-10
2.5.1 Overview ...............................................................................................................2-10
2.5.2 Structure and Principle..........................................................................................2-10
2.5.3 External Interfaces ................................................................................................ 2-12
2.5.4 Indices...................................................................................................................2-13
2.6 BASB ...............................................................................................................................2-13
2.6.1 Overview ...............................................................................................................2-13
2.6.2 Structure and Principle..........................................................................................2-13
2.6.3 External Interfaces ................................................................................................ 2-14
2.6.4 Indices...................................................................................................................2-14
2.7 BESP ...............................................................................................................................2-14
2.7.1 Overview ...............................................................................................................2-14
2.7.2 Structure and Principle..........................................................................................2-15
2.7.3 External Interfaces ................................................................................................ 2-16
2.7.4 Indices...................................................................................................................2-16

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2.8 BFAN ...............................................................................................................................2-17
2.8.1 BFMM....................................................................................................................2-17
2.8.2 BFIB ......................................................................................................................2-19
Chapter 3 Radio Frequency Subsystem ..................................................................................... 3-1
3.1 Overview............................................................................................................................3-1
3.1.1 Radio Frequency Subsystem Functional Structure.................................................3-1
3.1.2 Introduction to RF Modules..................................................................................... 3-2
3.2 BTRM.................................................................................................................................3-2
3.2.1 Overview ................................................................................................................. 3-2
3.2.2 Structure and Principle............................................................................................3-3
3.2.3 External Interfaces .................................................................................................. 3-5
3.2.4 Indices.....................................................................................................................3-6
3.3 BHPA.................................................................................................................................3-6
3.3.1 Overview ................................................................................................................. 3-6
3.3.2 Structure and Principle............................................................................................3-6
3.3.3 External Interfaces .................................................................................................. 3-8
3.3.4 Indices.....................................................................................................................3-8
3.4 BTRB .................................................................................................................................3-8
3.4.1 Overview ................................................................................................................. 3-8
3.4.2 Structure and Principle............................................................................................3-8
3.4.3 External Interfaces .................................................................................................. 3-9
3.4.4 Indices...................................................................................................................3-10
3.5 CDU.................................................................................................................................3-10
3.5.1 Overview ...............................................................................................................3-10
3.5.2 Structure and Principle..........................................................................................3-10
3.5.3 External Interfaces ................................................................................................ 3-11
3.5.4 Indices...................................................................................................................3-12
3.6 DFU..................................................................................................................................3-12
3.6.1 Overview ...............................................................................................................3-12
3.6.2 Structure and Principle..........................................................................................3-12
3.6.3 External Interfaces ................................................................................................ 3-13
3.6.4 Indices...................................................................................................................3-13
3.7 DDU.................................................................................................................................3-14
3.7.1 Overview ...............................................................................................................3-14
3.7.2 Structure and Principle..........................................................................................3-14
3.7.3 External Interfaces ................................................................................................ 3-15
3.7.4 Indices...................................................................................................................3-15
3.8 RLDU...............................................................................................................................3-16
3.8.1 Overview ...............................................................................................................3-16
3.8.2 Structure and Principle..........................................................................................3-16
3.8.3 External Interfaces ................................................................................................ 3-17
3.8.4 Indices...................................................................................................................3-18

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3.9 BRFM...............................................................................................................................3-18
3.9.1 BBFM .................................................................................................................... 3-18
3.9.2 BBFL .....................................................................................................................3-20
Chapter 4 Antenna & Feeder Subsystem....................................................................................4-1
4.1 Overview............................................................................................................................4-1
4.2 RF Antenna & Feeder........................................................................................................4-1
4.2.1 Antenna...................................................................................................................4-1
4.2.2 Feeder.....................................................................................................................4-3
4.2.3 Lightning Arrester (Optional)...................................................................................4-3
4.2.4 Tower-top Amplifier (Optional)................................................................................ 4-4
4.3 Satellite Synchronization Antenna & Feeder.....................................................................4-4
4.3.1 Overview ................................................................................................................. 4-4
4.3.2 Antenna...................................................................................................................4-7
4.3.3 Feeder.....................................................................................................................4-7
4.3.4 Lightning Arrester.................................................................................................... 4-7
4.3.5 Receiver..................................................................................................................4-7
Chapter 5 Power & Environment Monitoring Subsystem ......................................................... 5-1
5.1 Overview............................................................................................................................5-1
5.2 Power Distribution..............................................................................................................5-2
5.2.1 AC Distribution ........................................................................................................5-2
5.2.2 DC Distribution........................................................................................................ 5-3
5.2.3 Power Distribution Devices.....................................................................................5-5
5.3 Environment Monitoring.....................................................................................................5-6
5.3.1 Structure of Monitoring System............................................................................... 5-6
5.3.2 Monitoring Devices.................................................................................................. 5-7
Chapter 6 Lightning Protection and Grounding......................................................................... 6-1
6.1 Overview............................................................................................................................6-1
6.2 BTS Lightning Protection Principle....................................................................................6-1
6.2.1 Principle and Characteristics...................................................................................6-1
6.2.2 Lightning Protection for AC Power.......................................................................... 6-2
6.2.3 Lightning Protection for Trunk Cables.....................................................................6-2
6.2.4 Lighting Protection for Antenna & Feeder Subsystem............................................ 6-3
6.3 Grounding of BTS Equipment............................................................................................6-4
6.3.1 Internal Grounding of Cabinet.................................................................................6-4
6.3.2 External Grounding of Cabinet................................................................................6-4
6.3.3 Grounding of AC Lightning Arrester........................................................................ 6-4
6.3.4 Grounding of Transmission Equipment...................................................................6-5
6.3.5 Grounding of Overhead E1/T1 and HDSL Cables.................................................. 6-5
6.3.6 Grounding of BTS Surge Protector......................................................................... 6-5
Chapter 7 BTS Signal Flows.........................................................................................................7-1
7.1 Overview............................................................................................................................7-1

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7.2 Abis Traffic Signal Flow .....................................................................................................7-3
7.3 Abis Signaling Message Flow............................................................................................7-4
7.4 O&M Signal Flow...............................................................................................................7-5
7.5 Clock Signal Flow ..............................................................................................................7-5
Chapter 8 BTS Configuration.......................................................................................................8-1
8.1 Configuration Principle.......................................................................................................8-1
8.2 Configuration of Main Equipment ......................................................................................8-1
8.2.1 Configuration of Baseband Boards.........................................................................8-1
8.2.2 Configuration of RF Modules ..................................................................................8-3
8.2.3 Configuration of Power Modules.............................................................................8-5
8.3 Configuration of Auxiliary Equipment.................................................................................8-5
8.3.1 Batteries..................................................................................................................8-5
8.3.2 Temperature Control Device................................................................................... 8-6
8.3.3 Monitoring Devices.................................................................................................. 8-6
8.3.4 Transmission Equipment.........................................................................................8-7
8.4 Configuration of Antenna and Feeder ...............................................................................8-7
8.5 Networking Configuration ..................................................................................................8-7
8.5.1 Star Networking.......................................................................................................8-8
8.5.2 Chain Networking.................................................................................................... 8-9
8.5.3 Tree Networking....................................................................................................8-10
8.5.4 Fractional ATM Networking................................................................................... 8-11
8.5.5 Cascading with ODU3601Cs ................................................................................8-11
8.6 Typical Configurations .....................................................................................................8-12
8.6.1 Overview ...............................................................................................................8-12
8.6.2 S(2/2/2) Configuration...........................................................................................8-13
8.6.3 S(4/4/4) Configuration...........................................................................................8-14
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-10
A.1.5 Limitations on Emissions......................................................................................A-12
A.1.6 Received Signal Quality Indicator (RSQI) ............................................................A-12
A.2 Performance of Transmitter.............................................................................................A-13
A.2.1 Frequency Requirements .....................................................................................A-13
A.2.2 Modulation Requirements.....................................................................................A-13
A.2.3 RF Output Power..................................................................................................A-14
A.2.4 Limitations on Emissions......................................................................................A-15
Appendix B EMC Performance ....................................................................................................B-1
B.1 EMI Performance...............................................................................................................B-1

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B.2 EMS Performance.............................................................................................................B-2
Appendix C Environment Requirements ....................................................................................C-1
C.1 Storage Environment ........................................................................................................C-1
C.2 Transportation Environment..............................................................................................C-3
C.3 Operation Environment.....................................................................................................C-5
Appendix D Electromagnetic Radiation......................................................................................D-1
D.1 Introduction........................................................................................................................D-1
D.2 Maximum Permissible Exposure.......................................................................................D-1
D.3 Estimation of Exposure to Electromagnetic Fields............................................................D-3
D.4 Calculation of Safe Distance.............................................................................................D-3
D.5 Location of BTS Antennae................................................................................................D-4
D.5.1 Exclusion Zones .....................................................................................................D-4
D.5.2 Guidelines on Arranging Antenna Locations..........................................................D-5
Appendix E Abbreviations and Acronyms .................................................................................E-1

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Chapter 1 Overall Structure
1.1 Physical Structure
A BTS3612A cabinet in full configuration is composed of two parts, as shown in Figure
1-1. The right half is the main cabinet, while the left half is for the auxiliary devices.
(1) Baseband subrack (2) Carrier subrack
(3) Duplexer subrack (4) AC distribution/lightning protector/wave filter unit
(5) Battery subrack (6)Power supply subrack
(7) Auxiliary cabinet secondary power switch box (8) Transmission equipment subrack
Figure 1-1 BTS3612A cabinet in full configuration
I. Main cabinet
The main cabinet is used to hold the baseband processing boards, Radio Frequency
(RF) modules, etc.
zBaseband subrack

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The baseband subrack is configured with various baseband processing boards, such
as BCIM, BCPM, BCKM and BRDM.
A main cabinet secondary power switch box is configured to the left of the subrack.
With the secondary power switch box, each board and module can be separately
powered by the PSUDC/DC. All the baseband processing boards share one power switch.
Each pair of BTRM and BHPA boards share one power switch. The RLDU has its own
power switch.
zCarrier subrack
There are two carrier subracks used to configure the carrier units, each of which is
composed of one BTRM and one BHPA. Each subrack can be configured with one
RLDU.
zDuplexer subrack
The duplexer subrack is located between the upper and lower carrier subracks. It is
configured with duplexer units DFU or DDU as needed.
To the right of the subrack is a lightning protector connecting to the GPS/GLONASS
synchronization antenna.
zOther devices
Between the baseband subrack and the upper carrier subrack are the fiber flange,
cabling trough, fan box and air inlet.
The cabling trough is used to route the satellite signal receiving cable and fibers
(connecting the BRDM and carrier modules). The extra fibers can be coiled on the fiber
flange.
The fan box, the air inlet and air outlet (on the top of the cabinet) form a ventilation path
to discharge the heat in the baseband subrack.
II. Auxiliary cabinet
The auxiliary cabinet is configured with the PSUAC/DC, PSUDC/DC, storage batteries, and
built-in transmission equipment.
zTransmission equipment subrack
Standard space is reserved in this subrack to accommodate microwave, High-speed
Digital Subscriber Line (HDSL), or SDH transmission equipment so as to support
various networking modes.
zPower supply subrack
The power supply subrack is configured with PSUDC/DC and PSUAC/DC. A Power
Monitoring Unit (PMU) can also be installed.
zBattery subrack

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The battery subrack can be configured with storage batteries or DC lightning
protector/wave filter, based on actual configuration requirements.
zOther devices
A lightning protection board and an auxiliary cabinet secondary power switch box are
configured between the transmission equipment subrack and the power supply
subrack.
E1 Surge Protector (BESP) or SDH surge protector can be used, according to the
transmission equipment configured.
The secondary power switch box is used to control the power supply to the PSUAC/DC.
III. Cabinet door
Temperature-control device, such as air conditioner or heat exchanger, are equipped
on the cabinet door.
1.2 Functional Structure
Functionally, the BTS3612A system is composed of the baseband subsystem, Radio
Frequency (RF) subsystem, antenna & feeder subsystem, and power & environment
monitor subsystem, as shown in Figure 1-2.
BSC
Baseband
subsystem
Power & environment monitor subsystem
Radio Frequency
subsystem
Abis
interface
Um
interface
MS Antenna & feeder
subsystem
220V AC
or
110V AC
BTS3612A
Figure 1-2 BTS3612A system structure
Standard space is reserved in the cabinet to accommodate transmission equipment
such as microwave and SDH so as to support different networking modes.
The following chapters will detail each subsystem of BTS3612A.

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Chapter 2 Baseband Subsystem
2.1 Overview
Baseband subsystem consists of BTS Control & Clock Module (BCKM), BTS Resource
Distribution Module (BRDM), BTS Channel Processing Module (BCPM), BTS Control
Interface Module (BCIM) and Baseband Backplane (BASB).
2.1.1 Functional Structure
The functional structure of baseband subsystem is shown in Figure 2-1.
BCIM
BCK
M
E1/T1
BSC BCPM
BRD
M
...
...
Other functional units
BTRM/ODU3601C
BTRM/ODU3601C
BRDM
BCPM
BCKM
BCIM
Satellite signal receiving
antenna
Clock bus
Backplane bus
Emergency serial port
High-speed data
bus
Opticalfiber
BCIM: BTS Control Interface Module BCPM: BTS Channel Process Module
BCKM: BTS Control & Clock Module BRDM: BTS Resource Distribution Module
BTRM: BTS Transceiver Module BSC: Base Station Controller
Figure 2-1 functional structure of baseband subsystem
Baseband subsystem accesses transmission system through E1/T1 interface provided
by the BCIM so as to connect to BSC equipment. It connects to carrier units through
optical interface provided by the BRDM. Carrier units can be BTRM modules of the
same BTS, or MTRM module of the ODU3601C extended afar.
2.1.2 Introduction to Baseband Boards
Baseband subsystem is held in the baseband subrack. The full configuration of
baseband subrack is as shown in Figure 2-1
Baseband subrack supports the following boards:

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zBCKM: BTS control & clock module, providing clock for BTS system and realizing
the control of BTS system resource.
zBCIM: BTS control interface module, used for accessing transmission system to
connect to the BSC. It supports E1/T1 transmission.
zBCPM: BTS channel process module, processing the data of CDMA forward
channel and reverse channel.
zBRDM: BTS resource distribution module, connecting BCPM to BTRM to realize
the work mode of BCPM resource pool.
In addition to the boards introduced, this section also covers the backplane of
baseband subrack, E1 lightning-protection board and fan module.
2.2 BCKM
2.2.1 Overview
BCKM controls and manages the entire BTS system. Its functions are listed as follows:
Main control functions: Call procedure control, signaling processing, resource
management, channel management, cell configuration, etc.
Operation & maintenance functions (O&M): BTS operation and maintenance, such as
software download, status management, data configuration, test management,
interface tracing, fault management, log management, maintenance console interface,
active/standby BCKM switchover, etc.
Clock function: It provides high-precision oscillation clock and can be synchronized
with an external clock (such as GPS/GLONASS clock). Thus it provides the entire BTS
system with reference clock signal.
In addition, BCKM also provides external interfaces. See the following sections for
detail.
2.2.2 Structure and Principle
The structure of BCKM module is as shown in Figure 2-2.

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Power supply
module
External
communication
module
Clock
module
Backplane
bus module
Other
functional
units CPU
module
BCKM
...
Satellite
signal
receiver
BASB
BASB
Figure 2-2 Structure of BCKM module
The BCKM comprises the following parts:
I. Clock module
Clock module is the clock source of BTS, which provides working clock for various
boards.
Clock module supports two work modes: External synchronization mode (locked mode)
and free oscillation mode (holdover mode). In the former mode, it receives
GPS/GLONASS clock signals through its satellite signal receiver. In the latter mode, it
provides clock reference through high precision oscillator (oven control & voltage
control oscillator).
For the introduction to satellite signal receiver, see “4.3.5 Receiver”.
II. CPU module
CPU module controls logical circuits to initialize relevant components. The
management and control of BTS system is implemented through its system software,
which includes main control software and operation & maintenance software. For
specific function, see ”2.1 Overview”.
III. Backplane bus module
The communication port of the Central Processing Unit (CPU) is connected with other
boards of BTS through the backplane bus module, and processes or transmits O&M
signaling from other boards of BTS (BRDM, BCPM and BCIM).
IV. External communication module
External communication module utilizes the multiple communication control ports
provided by the main control CPU to implement functions such as maintenance

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console interface, environment monitoring interface, test interface and external
synchronization interface.
V. Power supply module
The power supply module converts +24V input power into +5V, +3.3V and +2.5V for
various modules of local board.
2.2.3 External Interfaces
zLocal maintenance console interface
This interface is a 10/100M compatible Ethernet interface to connect with local
maintenance console.
zRemote maintenance serial port
This port is a RS232 serial port to connect with the Modem so as to provide remote
monitoring and maintenance in case of interruption of OML link.
zEnvironment alarm interface
This port is a RS485 serial port to connect with an external monitoring device so as to
collect and process the equipment room environment information (such as fire, water,
temperature and humidity alarms).
zGPS/GLONASS antenna interface
It is used to receive satellite signal from the GPS/GLONASS so as to provide
GPS/GLONASS antenna with +5V feed.
zExternal synchronization interface
If the GPS/GLONASS is not available, the system clock can keep synchronization with
external clock system.
zTest interface
It is an interface for BTS test, providing 10MHz and 2s signals
zBackplane interface
It includes backplane bus interface, clock bus interface, and emergency serial port. The
board management is accomplished through backplane bus. Other boards are
provided with clock signal through clock bus. Boards can still keep communication
through emergency serial port in case of board fault.
zFan module interface
Fan module interface is a RS485 serial port, used to monitor the fan module and power
supply module of baseband subrack.
zPower supply interface
Led out from the power connector on the backplane, the interface is connected with
+24V power, +24V power ground and PGND.

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2.2.4 Indices
zPower voltage: +24V.
zPower consumption: <20W.
zDimensions: 460mm%233.35mm (Length%Width).
2.3 BCIM
2.3.1 Overview
The BCIM is located in BTS baseband subrack. It is a functional entity for the
connection of BTS and BSC. Its major functions are as follows:
zIn uplink direction, backplane bus receives O&M command from BCKM and traffic
data from BCPM, and transmit ATM cells on the multiple E1 links to BSC with IMA
technology in compliance with G.804 standards.
zIn downlink direction, it receives ATM cells distributed on the multiple E1/T1 links
from BSC, multiplexes them into a single ATM cell flow with IMA technology and
finally sends them to corresponding processing boards through the backplane
bus.
zEach BCIM provides 8 E1/T1 links, which can support at the most 4 IMA link sets.
In BTS, there are two BCIMs, working in load sharing mode and providing physical
interfaces to BSC. At the most 16 E1/T1 links can be provided.
zIt communicates with BSC through IMA state machine program on the local board
and monitors the working status of E1/T1 link to ensure the implementation of IMA
protocol.
zIt transmits O&M command through backplane bus or emergency serial port,
reports the status information of the local board to BCKM and provides interface
for board maintenance and network management.
2.3.2 Structure and Principle
BCIM is available in two specifications:
zBCIM with E1 interface.
zBCIM with E1/T1 interface. This type of BCIM workseither in E1 mode or T1 mode
according to the setting of the DIP switches.
Figure 2-3 illustrates the structure of BCIM with E1/T1 interface.

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Backplane bus
module CPU module
Control bus
Data bus
E1/T1
RS232
BASB
BCKM
BESP
IMA
module
...
Power supply
module
Clock
module
Figure 2-3 Structure of BCIM
BCIM comprises the following parts:
I. IMA module
IMA module inversely multiplex an ATM cell flow based on cells into multiple physical
links for transmission, and remotely multiplex the cell flows transmitted on different
physical connections into a single ATM cell flow.
In uplink direction, IMA module receives AAL2 traffic cells from BCPM and AAL5
signaling cells from BCKM through the backplane bus. It splits the ATM cell flow into
cells, transmits them on multiple E1/T1 link according to G.804 standard before
sending them to BSC.
In downlink direction, it receives ATM cells from BSC that are distributed on multiple
E1/T1 trunk lines, inversely multiplexes them into a single ATM cell flow. Then it sends
AAL2 traffic cells to BCPM and AAL5 signaling cells to BCKM through the backplane
bus.
II. CPU module
The CPU module implements such functions as IMA protocol processing, executing
OAM function of IMA, as well as E1/T1 link management and communication with
BCKM.
III. Backplane bus module
BCIM communicates with other boards in the baseband part throughthe backplane bus
module, including control information communication with BCKM and traffic data
communication with BCPM.

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IV. Clock module
It provides working clock for the local board.
V. Power supply module
The power supply module converts +24V input power into +3.3V for various modules of
local board.
2.3.3 External Interfaces
zE1/T1 interface
Interface with BSC. BTS can be connected to the transmission system to connect to the
BSC.
zBackplane bus interface
Interface with the other boards in the baseband part.
zEmergency serial port
Emergency serial port is an RS-232 serial port, works as a slave node and is used for
communication with BCKM when other part of the board is faulty.
zPower supply interface
Led out from the power connector on the backplane, the interface is connected with
+24V power, +24V power ground and PGND.
2.3.4 Indices
zPower voltage: +24V.
zPower consumption <15W.
zDimensions: 460mm%233.35mm (Length%Width).
2.4 BCPM
2.4.1 Overview
The BCPM is logically located between the BRDM and the BCIM. The BCPM is the
traffic processing board of the system. In full configuration, six BCPMs are needed.
Data from various forward and reverse channels are processed by this board.
The BCPM also processes digital signals, including encoding/decoding baseband
signals and one-time modulation and demodulation of baseband signals. In addition, it
processes high layer control signals. The main functions are as follows:
zIn forward direction, after ATM cell data from the network side are processed by
the high performance processor, BCPM performs functions such as encoding

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(convolutional code, TURBO code), interleaving, spreading, modulation and data
multiplexing, and converts them into high-speed signals. Then the signals are
processed by a dedicated processing chip and transmitted through the radio
interface side of the channel processing board.
zIn reverse direction, data received by BCPM are demultiplexed, demodulated,
de-interlaced and decoded (convolutional code, TURBO code). Then under the
control of the high performance processor, the data are sent to BSC via BCIM in
the form of ATM cells.
zThe BCPM supports in-board and inter-board daisy chains, forming a
resource-processing pool.
zHigh performance processor with two kernels and internal cache.
2.4.2 Structure and principle
The BCPM comprises the following parts as shown in Figure 2-4:
Multiplex/demultiplex
module Baseband
processing
module
CPU module
Backplane
bus module
Power supply
module
BCPM
BASB
Control bus
Clock
module
BRDM Data bus
RS232 BCKM
High
speed
data bus
Data bus
Data bus
Figure 2-4 Structure of BCPM
I. Multiplex/demultiplex module
In forward direction, baseband data in the channel processing board are multiplexed
into high-speed signals and sent to radio side in the form of differential signals. In
reverse direction, the high-speed differential signals are demultiplexed and sent to
baseband processing chip.
II. Baseband processing module
The QUALCOMM new generation processing chip is used to perform forward and
reverse baseband data processing. With the help of in-board and inter-board data

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daisy chains, channel processing capability is increased greatly. Maximally 6 sectors
can be supported.
III. CPU module
The high performance control CPU on BCPM mainly processes the forward & reverse
high-speed traffic data and control data and reports board status. At the network side,
the processing module receives control signaling, receives/transmits ATM cells and
communicates with BSC through BCIM. At the radio side, it controls the dedicated
baseband processing chip to generate orthogonal (IQ) data. After multiplexing, the data
pass BRDM as high-speed differential signals, to implement data exchange with radio
side.
IV. Backplane bus module
The BCPM communicates with other boards in the BTS baseband part through
backplane bus, including control information communication with BCKM and traffic data
communication with BCIM.
V. Clock module
The clock module performs double-frequency phase-locking to the clock signals from
the backplane, provides clock for boards, and drives and co-phases the clock signals
generated on the local board, to get satisfactory clock signals.
VI. Power supply module
The power supply module converts +24V input power into +3.3V for various modules of
local board.
2.4.3 External Interfaces
zHigh-speed data bus interface
Interface with BRDM.
zBackplane bus interface
Interface with other boards of baseband part
zEmergency serial port
Emergency serial port is an RS-232 serial port, works as a slave node and is used for
communicating with BCKM when other part of the board is faulty.
zPower supply interface
Led out from the power connector on the backplane, the interface is connected with
+24V power, +24V power ground and PGND.

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2.4.4 Indices
zPower voltage: +24V.
zPower consumption <30W.
zDimensions: 460mm%233.35mm (Length%Width)
2.5 BRDM
2.5.1 Overview
The BRDM is logically located between BTRM and BCPM, providing path for
orthogonal data connection (IQ) and exchange between the two so as to support the
flexible configuration relation between BCPM and BTRM. The BRDM also support
daisy chain cascading between BCPMs.
Data from the BTRM is sent to the BRDM through optical fibers. Then the BRDM
distributes the data before sending them to BCPMs via the high-speed data bus. With
the function of building cascades of daisy chain for BCPMs, the BRDM connects the
short daisy chain cascades to form standard daisy chain cascades of a certain length.
This facilitates the utilization of channel resource and flexible configuration of the
channel capacity of each sector carrier.
The BRDM has the following functions and features:
zOptical interfaces are configured to provide high-speed data paths to BTRM/
ODU3601C.
zSix pairs of high-speed data bus interfaces are provided tosix BCPM slots through
the backplane.
zFlexible data distribution and exchange between BTRM/ODU3601C and BCPM
are enabled.
zFlexible data exchange between BCPMs is enabled. It can be cascaded to form
daisy chains, so BCPM resource pool can be achieved. The resource pool
improves the utilization ratio of channel resource and makes the configuration of
channel capacity of each sector carrier flexible.
zIt exchanges O&M information with the BCKM through the backplane bus or
emergency serial port.
It forwards and receives O&M information of BTRM/ODU3601C via optical fibers and
provides O&M links between the baseband subrack and BTRM/ODU3601C.
2.5.2 Structure and Principle
The BRDM has two specifications as follows:

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zThe BRDM configured with six pairs of multi-mode optical interfaces used to
connect to the BTRM.
zThe BRDM with three pairs of single-mode optical interfaces used to cascade with
ODU3601C.
The two specifications differ in optical modules configured.
The structure of BRDM is shown in Figure 2-5.
Optical
module High-speed
data
interface Switching
module
CPU
module
Bus
interface
module
4 high-speed
data buses
Power supply
module
Optical
Optical
Optical
Optical
Optical
Optical
Clock
module
Optical
module
Optical
module
Optical
module
Optical
module
Optical
module
High-speed
data
interface
High-speed
data
interface
RS232
BTRM BCPM
Backplane
bus
BCKM
BCPM
BCPM
BCPM
BTRM
BTRM
BTRM
BTRM
BTRM
BRDM
High-speed
data
interface
High-speed
data
interface
High-speed
data
interface
4 high-speed
data buses
4 high-speed
data buses
4 high-speed
data buses
Figure 2-5 Structure of BRDM module (6 pairs of multi-mode optical interfaces)
The BRDM is composed of optical module, high-speed data interface module,
switching module, CPU module, bus interface module, power supply module and clock
module.
I. Optical module
The optical module converts optical signals into electrical signals. The BRDM can be
classified into single-mode BRDM and multi-mode BRDM according to different types
of optical module.
The multi-mode BRDM is equipped with six optical modules and provides six pairs of
optical interfaces. It is used to connect to the BTRM in the same BTS.
The single-mode BRDM is equipped with three optical modules and provides three
pairs of optical interfaces. It is used to cascade with ODU3601C.The single-mode
BRDM can be further classified into two kinds, namely 10km and 70km, according to
the transmission capability of the optical module.

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II. High-speed data interface module
The high-speed data interface module converts rates of high-speed signals for the
convenient processing of the switching module.
III. Switching module
The switching module segments and paste data as required. It is a core processing
module of this board. Data from BTRM/ODU3601C are sent to this board, where the
switching module will distribute and paste them before sending them to the BCPM. The
switching module can also provide daisy chain cascading for the BCPMs through the
distribution and pasting of data.
IV. CPU module
The CPU module processes O&M information and configures switching parameters.
The O&M information from the BCKM is sent to this board via the bus interface module.
Then the CPU module processes the information and sends some specific O&M
information to the corresponding BTRM/ODU3601.
V. Bus interface module
This module provides the conversion of interfaces between the board and the
backplane, and provides a path for O&M information between this board and the
backplane.
VI. Clock module
The clock module performs double-frequency phase-locking to the clock signals from
the backplane. It provides clocks for boards, and drives and co-phases the clock
signals generated on the local board to get satisfactory clock signals.
VII. Power supply module
The power supply module converts +24V input power into +3.3V and 1.8V for various
modules of the local board.
2.5.3 External Interfaces
zOptical interface
There are two specifications of optical interface available according to optical modules:
6 pairs and 3 pairs. They connect to the BTRM and the ODU3601C respectively,
transmitting orthogonal (IQ) data and O&M information.
zHigh-speed data interface