Huawei Technologies BTS3612A-1900 CDMA Base Station User Manual Part 3

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Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Table of Contents i 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Table of Contents ii 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Table of Contents iii 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Table of Contents iv 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Table of Contents v 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 1 Overall Structure 1-1 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. z Baseband subrack

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 1 Overall Structure 1-2 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. z Carrier 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. z Duplexer 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. z Other 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. z Transmission 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. z Power supply subrack The power supply subrack is configured with PSUDC/DC and PSUAC/DC. A Power Monitoring Unit (PMU) can also be installed. z Battery subrack

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 1 Overall Structure 1-3 The battery subrack can be configured with storage batteries or DC lightning protector/wave filter, based on actual configuration requirements. z Other 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. BSCBasebandsubsystemPower & environment monitor subsystemRadio FrequencysubsystemAbisinterfaceUminterfaceMS Antenna & feedersubsystem220V ACor110V ACBTS3612A 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.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-1 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. BCIMBCKME1/T1BSC BCPMBRDM......Other functional unitsBTRM/ODU3601CBTRM/ODU3601CBRDMBCPMBCKMBCIMSatellite signal receivingantennaClock busBackplane busEmergency serial portHigh-speed databusOptical fiber 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:

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-2 z BCKM: BTS control & clock module, providing clock for BTS system and realizing the control of BTS system resource. z BCIM: BTS control interface module, used for accessing transmission system to connect to the BSC. It supports E1/T1 transmission. z BCPM: BTS channel process module, processing the data of CDMA forward channel and reverse channel. z BRDM: 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.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-3 Power supplymoduleExternalcommunicationmoduleClockmoduleBackplanebus moduleOtherfunctionalunits CPUmoduleBCKM...SatellitesignalreceiverBASBBASB 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-4 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 z Local maintenance console interface This interface is a 10/100M compatible Ethernet interface to connect with local maintenance console. z Remote 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. z Environment 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). z GPS/GLONASS antenna interface It is used to receive satellite signal from the GPS/GLONASS so as to provide GPS/GLONASS antenna with +5V feed. z External synchronization interface If the GPS/GLONASS is not available, the system clock can keep synchronization with external clock system. z Test interface It is an interface for BTS test, providing 10MHz and 2s signals z Backplane 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. z Fan module interface Fan module interface is a RS485 serial port, used to monitor the fan module and power supply module of baseband subrack. z Power supply interface Led out from the power connector on the backplane, the interface is connected with +24V power, +24V power ground and PGND.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-5 2.2.4 Indices z Power voltage: +24V. z Power consumption: <20W. z Dimensions: 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: z In 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. z In 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. z Each 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. z It 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. z It 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: z BCIM with E1 interface. z BCIM with E1/T1 interface. This type of BCIM works either 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.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-6 Backplane busmodule CPUmoduleControl busData busE1/T1RS232BASBBCKMBESPIMAmodule...Power supplymoduleClockmodule 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 through the backplane bus module, including control information communication with BCKM and traffic data communication with BCPM.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-7 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 z E1/T1 interface Interface with BSC. BTS can be connected to the transmission system to connect to the BSC. z Backplane bus interface Interface with the other boards in the baseband part. z Emergency 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. z Power 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 z Power voltage: +24V. z Power consumption <15W. z Dimensions: 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: z In forward direction, after ATM cell data from the network side are processed by the high performance processor, BCPM performs functions such as encoding

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-8 (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. z In 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. z The BCPM supports in-board and inter-board daisy chains, forming a resource-processing pool. z High 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/demultiplexmoduleBasebandprocessingmoduleCPU moduleBackplanebus modulePower supplymoduleBCPMBASBControl busClockmoduleBRDM Data busRS232 BCKMHighspeeddata busData busData 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

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-9 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 z High-speed data bus interface Interface with BRDM. z Backplane bus interface Interface with other boards of baseband part z Emergency 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. z Power supply interface Led out from the power connector on the backplane, the interface is connected with +24V power, +24V power ground and PGND.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-10 2.4.4 Indices z Power voltage: +24V. z Power consumption <30W. z Dimensions: 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: z Optical interfaces are configured to provide high-speed data paths to BTRM/ ODU3601C. z Six pairs of high-speed data bus interfaces are provided to six BCPM slots through the backplane. z Flexible data distribution and exchange between BTRM/ODU3601C and BCPM are enabled. z Flexible 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. z It 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:

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-11 z The BRDM configured with six pairs of multi-mode optical interfaces used to connect to the BTRM. z The 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 moduleHigh-speed data interfaceSwitching moduleCPU moduleBus interface module4 high-speed data busesPower supply moduleOpticalOpticalOpticalOpticalOpticalOpticalClock moduleOptical moduleOptical moduleOptical moduleOptical moduleOptical moduleHigh-speed data interfaceHigh-speed data interfaceRS232BTRM BCPMBackplane busBCKMBCPMBCPMBCPMBTRMBTRMBTRMBTRMBTRMBRDMHigh-speed data interfaceHigh-speed data interfaceHigh-speed data interface4 high-speed data buses4 high-speed data buses4 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.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-12 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 z Optical 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. z High-speed data interface

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-13 The interfaces are connected with six traffic slots (BCPM slots) through the backplane, for transmitting baseband orthogonal (IQ) data. z Backplane bus interface The interface is used for transmitting O&M information between BCKMs. z Clock interface The interface is connected with the BCKM via the backplane. It receives 2s, 16 %1.2288MHz clock signals and active/standby clock selection signal. z Emergency serial port Emergency serial port is an RS-232 serial port, works as a slave node and is used for communicating with the BCKM when other parts of the board are faulty. z Power supply interface Led out from the power connector on the backplane, the interface is connected with +24V power, +24V power ground and PGND. 2.5.4 Indices z Power voltage: +24V. z Power consumption <45W. z Dimensions: 460mm%233.35mm (Length%Width) 2.6 BASB 2.6.1 Overview The baseband backplane (BASB) is used to make interconnection of high-speed data links among the boards of baseband part, and exchanges various management and control information of boards with high-speed backplane technology. Specifically, the backplane: z Realizes interconnection of various signals between boards. z Supports hot plug/unplug of all boards. z Supports active/standby switchover of the BCKM. z Leads in system power supply and distributes the power to all boards. z Leads in signal monitoring lines for the fan subrack and the power subrack. z Provides protection against misplugging. 2.6.2 Structure and Principle Functions of the slots in the BASB are as shown in Figure 2-6.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-14 Figure 2-6 Functions of all slots in the BASB A backplane includes two parts: connector and board slot. The connector part includes 2 input connectors of backplane +24V power/ground, and 3 DB37 D-connectors. Power input connector, D-connector are all crimped devices. The slots of the backplane are defined as follows: z Slots 0~1 are for BCIMs. z Sots 5~6 are for BCKMs. z Slots 7~8 are for BRDMs. z Slots 2~4, 9~11 are for BCPMs. 2.6.3 External Interfaces The interfaces between the backplane and external devices include: z System power interface z Remote maintenance serial port z Environment alarm interface z Fan alarm serial port in baseband subrack z System external synchronization interface z Sixteen E1/T1 interfaces 2.6.4 Indices z Dimensions: 368mm %262mm (Length%Width) 2.7 BESP 2.7.1 Overview The E1 Surge Protector (BESP) is placed between the transmission equipment subrack and the power supply subrack. It is a functional entity for the BTS to implement

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-15 lightning protection with E1/T1 trunk line. The 8 pairs of lightning protection units of the BESP are used to discharge transient high voltage on the sheath and core of E1/T1 trunk line to the PGND. 2.7.2 Structure and Principle I. Structure The structure of BESP is shown in Figure 2-7. 8 E1s/T1s4 E1s/T1s4 E1s/T1sInterfaceDB37BSCInterfaceDB25InterfaceDB25BESP...BSCBCIM......Level-1 protectionLevel-2 protectionPGND Level-1 protectionLevel-2 protectionPGNDLevel-1 protectionLevel-2 protectionPGND... Figure 2-7 Structure of BESP The board consists of three parts: DB25 connector, lightning protection unit and DB37 connector. z Lightning protection unit E1/T1 lightning protection unit has two inbound lines connected with DB25, two outbound lines connected with DB37, and one PGND. Here PGNDs of all lightning protection units can be interconnected. z DB37 connector The DB37 is a male connector, connected with eight E1/T1 cables. z DB25 connector

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-16 The DB25 is a female connector. There are two DB25 connectors, respectively connected with four E1/T1 cables. II. Principle of lightning protection The principle of lightning protection is shown in Figure 2-8. Core SheathPGNDLead inDB25Lead outDB37 Figure 2-8 Principle of E1/T1 lightning protection When the BTS E1 trunk line is struck by lightning, high voltage will arise first on the DB25 and then spread to the lightning protection units. The lightning protection units have two protection levels: air discharge tube and voltage limit mesh. The air discharge tube discharges the high voltage to the ground and lowers it to 600V below. Then the voltage limit mesh further lowers the voltage to 30V below. 2.7.3 External Interfaces z E1/T1 interface Interface with the BSC (DB25). Connection with the BCIM (DB37) 2.7.4 Indices z Bearable surge current: >10kA (common mode), >5KA (differential mode) z Output residual voltage: <30V. z Dimensions: 140mm %120mm (Length%Width)

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-17 2.8 BFAN The fan module (BFAN) is installed right under the baseband subrack, serving as a part of the blower type cooling system of the baseband subrack. The BFAN consists of fan boxes and fan enclosures. Each fan box contains four fan units (24V DC brush-free fan) and one BTS Fan Monitor Module (BFMM). . The fan enclosure is used for installation of fan boxes, whose outside is the BTS3612A Fan Block Interface Board (BFIB) providing a system interface. The structure of BFAN is shown in Figure 2-9. (3)(2)(5)(4)(6)(7)(8)(3)(2)(5)(4)(6)(7)(8) (1) Fan box (2) LED indicator (3) Fan enclosure (4) BFIB (5) System signal interface (6) Power input interface (7) Blind mate connector (8) BFMM Figure 2-9 Structure of BFAN 2.8.1 BFMM I. Overview Built in the fan box, the BTS Fan Monitor Module (BFMM) communicates with the BCKM and receives instructions from the BCKM. It can make speed adjustment of the PWM on the fan units and report board status information to the BCKM when it is

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-18 queried. It can also guarantee a safe and proper cooling system and lower the system noise. Its main functions are as follows: z Control rotating speed of the fans. z Check whether fan units are in position and report their information. z Check and report fan unit blocking alarm. z Drive fan operating status indicator. z Communicate with the Main Control Unit (MCU) of BCKM and report in-board status information. II. Structure and principle The position of BFMM is shown in Figure 2-9. And its function is shown in Figure 2-10. Main control unitPower supply moduleTemperature collection moduleCommunication moduleFan-in-position & faultdetection moduleFan drive moduleSwitch value alarm moduleIndicator drive module Figure 2-10 Functions of BFMM z Power supply module The power supply module converts +24V input power into the voltage required by various modules of local board. z Main Control Unit (MCU) The MCU controls the fans and communicates with the BCKM. That is: - Generates control PWM signals according to the instruction sent from the BCKM to control the speed of fans. - Detects fan alarm signal and in-board logic alarm signal, and reports them to the BCKM. - Generates panel indicator signals. z Communication module The module performs serial communication with the BCKM. z Fan driving module

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-19 The PWM control signal generated in the MCU provides controlled power input for fans by isolating driving circuits. z Fan in position and fault detection module This module isolates the fan-in-position signal and fan blocking alarm signal, then converts them into logic level for the MCU to sample and analyze. z Temperature collection module The module collects the ambient temperature information of BFMM in real time, which is realized by the MCU in query operation. z Indicator driving module: When a functional alarm (such as communication interruption in main control mode) occurs to the board or a fan blocking alarm occurs to the motor, this module provides a LED optical alarm interface inside the fan block, to drive the LED indicator on the fan block front panel. III. External interface z Power interface The interface is used to lead in working power for the BFMM. z Communication serial port Serial port communication ports 0 and 1 provide access for system active/standby serial port. When the system has only one serial port, only port 0 is used. z LED indicator driving output interface This is the driving interface for LED status indicator on the panel of the fan box. z Fan unit driving interface Maximally six such interfaces are provided. They also serve as the interfaces for fan-in-position detection and fan blocked detection. IV. Indices z Power voltage: +24V. z Power consumption <5W. z Dimensions: 280mm%35mm (Length%Width) 2.8.2 BFIB I. Overview The BTS Fan Block Interface Board (BFIB) provides electrical connection between fan boxes and the system. On one hand, it provides blind mate interfaces for the fan boxes. On the other hand, it provides the system with power interfaces and serial communication interfaces.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 2 Baseband Subsystem 2-20 II. Structure and principle The position of BFIB is shown in Figure 2-9. The BFIB implements interface conversion function. Refer to "3) Interface" for the definition of interfaces. Its structure is shown in Figure 2-11. (1) MOLEX connector (2) Large 3PIN power socket (3) DB-15 signal socket Figure 2-11 Illustration of BFIB structure III. External interface z Fan box electrical interface Power supply ports and serial port communication ports are provided for the fan boxes through MOLEX connectors. z System power supply interface The interface leads in the system power through big 3-pin connectors. z System serial communication interface External serial communication interface is provided through the DB-15. IV. Indices Dimensions: 230mm%30mm (Length%Width)

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-1 Chapter 3 Radio Frequency Subsystem 3.1 Overview 3.1.1 Radio Frequency Subsystem Functional Structure The structure of RF (radio frequency) subsystem is shown in Figure 3-1. CDURLDUBHPABHPABTRMBTRMAntenna & feederBRDM BRDM BRDM: BTS Resource Distribution Module BTRM: BTS Transceiver Module BHPA: BTS High Power Amplifier Unit CDU: Combining Duplexer Unit RLDU: Receive LNA Distribution Unit Figure 3-1 Structure of RF subsystem  Note: The above figure illustrates the duplexer configuration for 800MHz band. For 800MHz band, the duplexer can also be DDU. For 450MHz band, the duplexer can be DFU, DDU or CDU. For 1900MHz band, the duplexer can be DDU or CDU. The RF subsystem is connected with the BCIM of the baseband subsystem via the optical interface provided by the BTRM, and connected with the antenna & feeder subsystem via the feeder interface provided by a CDU, DDU, or DFU. It implements the following functions:

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-2 In forward link, it performs power adjustable up-conversion and linear power amplification to the modulated transmission signals, filtering the transmission signals to meet the corresponding air interface standard. In reverse link, it filters the signals received by the BTS antenna to suppress out-band interference, and then performs low-noise amplification, noise factor adjustable frequency down-conversion, and channel selective filtering. 3.1.2 Introduction to RF Modules The RF subsystem is composed of RF modules. Figure 8-3 shows the RF subsystem in full configuration. RF modules include: z BTRM: Complete the modulation/demodulation of baseband signal and up/down conversion. z BHPA: Complete the high-power linear amplification of transmitting carrier signals. z DFU: Complete the wave filtering and duplex isolation of one main transmitting/receiving signal, and the wave filtering of diversity receiving signal. It is one of the RF front-end modules. z DDU: Complete the isolation and duplex filtering of two receiving/transmitting signals. It is one of the RF front-end modules and is not equipped with the combiner function. z CDU: Complete the combination and wave filtering of two transmitting signals, duplex isolation of main transmitting and receiving signals, and the wave filtering of diversity receiving signal. It is one of the RF front-end modules. z RLDU: Complete the low noise amplification and dividing of receiving signals. Besides the above modules, the backplane of RF module and the RF fan module will also be introduced in this chapter. 3.2 BTRM 3.2.1 Overview In reverse link, the BTS Transceiver Module (BTRM) receives the main/diversity RF signals from the RLDU, and then changes the RF signals into baseband signals through down-conversion, wave filtering and multiplexing. Finally the BTRM sends the baseband signals to the baseband subsystem through the BRDM. In forward link, the BTRM receives the baseband signals from the BRDM, then changes the baseband signals into RF signals through de-multiplexing, wave filtering and up-conversion. Finally the BTRM sends the RF signals to the RF subsystem through the RF front module such as CDU.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-3 The BTRM also receives the management and configuration information from the BCKM, and reports the status and alarms of itself to the BCKM. 3.2.2 Structure and Principle The BTRM consists of BTS Intermediate Frequency Module (BIFM) and BTS Radio up-down Converter Module (BRCM). Its structure is shown in Figure 3-2. FIR &DAGCDACDemultiplexer/multiplexerADCPowerCPU Clock Optical interfaceDownconverter ADC FilterBHPALocal oscillatorBRCMRLDUBIFMRLDUBRDM+24VMain receiverDiversity receiverTransmitterBHPA PSUFilterFilterDownconverterUpconverterFIR &DAGC Figure 3-2 Structure of BTRM I. BIFM The BIFM consists of up-converter, down-converter, multiplexer/demultiplexer, optical interface, clock, CPU, and power supply sub-unit. It is in charge of the conversion between the analog intermediate frequency signal and the digital baseband signal, and the control of the BTRM. The functions of each sub-unit are as below: z Up-converter The up-converter accomplishes the wave filtering, digital up-conversion and digital-analog conversion of the signals in the transmit path. On receiving the baseband I/Q signals that have been de-multiplexed, the up-converter performs digital up-conversion after baseband filtering. Then the digital intermediate frequency signals are converted into analog intermediate frequency signals after digital-analog conversion and wave filtering. At last, the analog intermediate frequency signals are sent to the transmitter in BRCM via radio frequency (RF) interface. z Down-converter The down-converter accomplishes the analog-digital conversion, digital down-conversion and baseband filtering of the signals in the receive path.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-4 On receiving the analog intermediate frequency signals via the radio interface, the down-converter converts them into digital intermediate frequency signals via analog-digital conversion. Then the digital intermediate frequency signals are converted into baseband I/Q signals via digital down-conversion and baseband filtering. As last, the I/Q signals are transmitted to the demultiplexer/multiplexer. z Demultiplexer/multiplexer Under the control of the CPU, the demultiplexer/multiplexer de-multiplexes the forward I/Q signals, and multiplexes the reverse I/Q signals. At the same time, it multiplexes/de-multiplexes the operation & maintenance (O&M) signals of the OML. z Optical interface The optical interface performs channel coding and decoding, and accomplishes optical-electrical signal conversion and electrical-optical signal conversion. It is the interface between the BIFU and the BRDM of the upper-level BTS, and the interface between the BIFU and the MTRM (Micro-bts Transceiver Module) in the lower-level SoftSite. z Clock The clock generates all the clock signals needed by the BIFU, which include the clocks for up/down conversion, analog-digital conversion (ADC), and digital-analog conversion (DAC), as well as other working clocks. It also provides the reference clock for the BRCM. z CPU The CPU is in charge of the control of BTRM, which includes the initialization upon power-on, alarm collecting and reporting, and processing operation & maintenance related messages. z Power supply With input voltage of +24V, the power supply sub-unit provides power supply to BIFU and BRCU. II. BRCM The BRCM consists of transmitter, main/diversity receiver and local oscillator. It up-converts, amplifies the intermediate frequency signals output by BIFM, and performs spuriousness-suppression wave filtering. It also performs analog down-conversion, amplification of BTS main/diversity receiving signal input from the RLDU, and channel-selection wave filtering. The functions of each sub-unit are as below. z Transmitter When receiving the modulated analog intermediate frequency signals output by BIFM, the transmitter converts them to specified RF band via two times of up-conversions. Before and after the up-conversion, wave filtering, signal amplification and power

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-5 control are performed, so as to ensure the RF signals output meet the protocol requirements on power level, Adjacent Channel Power Radio (ACPR) and spuriousness. z Main/diversity receiver The main/diversity receiver converts the RF signals output by RLDU to specified intermediate frequency signals via down-conversion, and performs wave filtering, signal amplification and power control before/after the down-conversion, so as to ensure the intermediate frequency signals output can be received by BIFM. z Local oscillator The local oscillator consists of intermediate frequency source, transmit RF synthesizer and receive RF synthesizer. The intermediate frequency source generates the local oscillator signals for intermediate frequency up conversion in transmit path. The transmit RF synthesizer generates the local oscillator signals for the up-conversion of the transmit path. The receive RF synthesizer generates the local oscillator signals for the down conversion of main/diversity receive path. 3.2.3 External Interfaces There are interfaces between the BTRM and the BHPA/RLDU/BRDM/PSU. The descriptions of each interface are given as below: z RF interface between the BTRM and the BHPA The RF transmitting signal is output via this interface to BHPA, where the signal is amplified and then outputted. z RS485 interface between the BTRM and the BHPA This interface is used to transfer alarm and control signal, and power detection signal. z RF interface between the BTRM and the RLDU The main/diversity RF receiving signal output by RLDU is received via this interface. z Optical interface between the BTRM and the BRDM Baseband data are transmitted or received via this interface. z Power supply interface Interface with BTS3612A TRx Backplane (BTRB), This interface is used to provide +24V power supply to BTRM.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-6 3.2.4 Indices z Supported frequency band: 450MHz, 800MHz and 1900MHz z Power voltage: +24V z Power consumption: 51W z Dimensions: 460mm % 233.5mm % 64mm (Length % Width % Depth)  Note: BTRM supports the different frequency bands with different BTRM types, such as BTRM for 450MHz band, BTRM for 800MHz band, BTRM for 1900MHz band. And this principle also applies to the other RF modules including BHPA, CDU, DFU, DDU, and RLDU. 3.3 BHPA 3.3.1 Overview Located at the left side of the BTRM, the BTS High Power Amplifier Module (BHPA) amplifies the RF modulation signals output by BTRM. Its main functions are: z RF power amplification: The BHPA performs power amplification for the RF modulation signals from BTRM. z Over-temperature alarm: When the temperature of power amplifier base board exceeds a specified threshold, the BBFM will process the over-temperature alarm signal generated by HPAU and report it to BTRM. z Over-excited alarm: When the power level of BHPA input RF signal exceeds a specified threshold, the BBFM will process the over-excited alarm signal generated by HPAU and report it to BTRM. z Gain decrease alarm: When the gain of the power amplifier drops over 6dB, the BBFM will process the gain decrease alarm signal generated by HPAU and report it to BTRM. z Fan monitoring: The BBFM installed in BHPA performs such functions as fan alarm and power amplifier alarm signal processing & reporting, and fan speed adjustment. 3.3.2 Structure and Principle The structure of BHPA module includes the following parts, as shown in Figure 3-3:

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-7 RF inputCouplerPower amplificationRF outputBTRBCDUBTRMBBFMBDCSSampling port+24VBHPAAlarm signalAlarm signalAlarm circuitBTRMCirculatorHPAUz Figure 3-3 Functional structure of BHPA module I. HPAU The High Power Amplifier Unit (HPAU) consists of two parts: power amplifier and alarm circuit. The power amplifier amplifies the RF signals from BTRM. The amplified RF signals are then sent to CDU or DFU via BTRB. The alarm circuit monitors the power amplifier status and generates over-temperature alarm, over-excited alarm and gain decrease alarm signals when necessary. The alarm signals will be sent to BBFM, where they will be processed and reported to BTRB. The coupler is used to couple the RF output signals to the sampling port for test purpose. The output power of HPAU can be adjusted by controlling the RF output signal of BTRM. II. BBFM The BTS BTRM Fan Monitor (BBFM) processes fan alarm signals and power amplifier alarm signals, and sends them to BTRM via BTRB, and then BTRM will report them to upper level. BBFM can adjust the fan speed based on the ambient temperature and the actual BHPA output power in order to lower the noise of fans. For the detail of BBFM, see “3.9 BRFM”

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-8 3.3.3 External Interfaces External interfaces of the BHPA module are D-type combination blind mate connectors, including: z RF interface The RF interface of BHPA has one input port and one output port. They are connected respectively with BTRM RF output port via BTRB and CDU/DFU/DDU RF input port via coaxial cable. z Power supply interface Interface with BTS3612A TRx Backplane (BTRB), This interface is used to provide +24V power supply to BTRM. The +24V power is supplied with the BTS Direct Current Switch box (BDCS). z Alarm interface Interface with BTRM. Fan alarm signals and power amplifier alarm signals are sent via BTRB to BTRM. 3.3.4 Indices z Supported frequency band: 450MHz, 800MHz, and 1900MHz z Power supply: +24V z Power consumption: <380W z Dimensions: 460mm %233.5mm %64mm (Length % Width % Depth) 3.4 BTRB 3.4.1 Overview The BTS3612A TRx Backplane (BTRB) accomplishes the following functions: z Fastening the connection between BTRM and BHPA. z Fastening the RLDU. z Monitoring BHPA temperature. z Providing alarm signal interface between BTRM and RLDU. Key internal parts of BTRB include connectors and temperature sensors. 3.4.2 Structure and Principle The BTRB structure is as shown in Figure 3-4.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-9 RS485 RS485RLDU0RS485RS485RLDU1Temperature Sensor Temperature Sensor Temperature Sensor2mmHM A/N connnector24W7connnector2mmHM A/N connnector24W7connnector2mmHM A/N connnector24W7connnectorFunctional group 0 Functional group 1 Functional group 2 Figure 3-4 Functional structure of BTRB I. BTRM 2mm connector Each set of 2mm connectors includes one 5%22pin A-connector and three 3-socket- C4-connectors. A-connector transfers RLDU alarm signals from DB9 connector and RS485 interface message from BHPA 24W7 combination DB-connector. C4-connector transfers the main/diversity input/output RF signal of BTRM and +24V DC power signal needed by BTRM. II. BHPA 24W7 D-type combination blind mate connector Each 24W7 D-type combination blind mate connector includes two coaxial contacts (transferring BHPA input/output RF signals), two high-current power contacts (transferring +24V power supply and PGND signals), one set of RS485 signal contacts and a group of contacts for temperature sensor signals. III. DB9 connector There are two angled DB9 connectors on BTRB for two RLDUs alarm signals transferred to BTRM. IV. Temperature sensor There are three temperature sensors for the three BHPA slots, used for sensing the air temperature at each BHPA air outlet. They will convert the information into current and send to BFMM on BHPA for processing. In this way, fan speed can be controlled on a real-time basis. 3.4.3 External Interfaces See the introduction to connectors in Section 3.4.2.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-10 3.4.4 Indices Dimensions: 664mm%262mm%3mm (Length % Width % Depth) 3.5 CDU 3.5.1 Overview The Combining Duplexer Unit (CDU) accomplishes the following functions: z Combining two carrier signals from the two BHPAs into one. z Isolating and filtering the receiving and transmitting signals. z Filtering the transmitting signals so as to suppress BTS spurious emissions. z Filtering the receiving signals so as to suppress the interference from outside the receive band. Key internal parts of CDU include isolator, 2-in-1 combiner, duplexer, filter and directional coupler. 3.5.2 Structure and Principle CDU structure is as shown in Figure 3-5. ND-SUB SDN-Type SMA-TypeLPFLPF BPFDUPLEXERCOUPLERFILTER COMB.NNSSSDDDDDDTX-TESTTX/RXM-ANTRXD-ANTRXM-TESTRXD-TESTTX1Pf-OUTPr-OUTTX2RXM-OUTRXD-OUTLPFISOLATOR LPF: Low Pass Filter BPF: Band Pass Filter Figure 3-5 Structure of CDU

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-11 I. Isolator There are two isolators at each input port of the combiner in CDU. They are used to isolate the two carriers from two input ports. II. Combiner The combiner is a narrow band cavity filtering combiner. In comparison with broadband combiner, it features lower insertion loss and effective isolation. III. Duplexer The duplexer is used to isolate transmitted signals and received signals, suppress transmission spurious and reduce antenna quantity. IV. Filter The filter on the transmitting channel filters transmitting signal. The filter on the main/diversity receive channel filters main/diversity receive signals respectively. Then it sends them to low-noise amplifier in the RLDU for amplification. V. Directional coupler The directional coupler couples forward/reverse power to RLDU, and monitors the antenna VSWR. 3.5.3 External Interfaces The CDU is a module shared by the transmit and receive paths of the BTS. Therefore, it has interfaces with other modules both in the transmitting and in the receiving paths. Its external interfaces include a set of 8W8 D-type combination blind mate connectors on the backside, and a set of N-connectors and SMA connectors on the front side. The interface signals include: z RF signals between CDU combiner input ports and BHPA output ports. They are transferred through the blind mate connectors on the backside. z BTS receiving signals output from the duplexer. They are sent to RLDU via the blind mate connector on the backside. z BTS transmitting signals, which are transferred to the cabinet-bottom antenna interface through the RF cable connected with the N-connector at the front side of CDU. z BTS receiving signals, which are transferred from the cabinet-bottom antenna interface through the RF cable connected with the N-connector on the front side of CDU.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-12 z Forward/reverse coupled RF signals, which are sent to RLDU via the blind mate connector on the backside. z Forward/reverse coupled test signals, which are output through the standard SMA connector on the front side of CDU. 3.5.4 Indices z Number of combined signals: 2 z Supported frequency band: 450MHz, 800MHz, and 1900MHz. Module dimensions: 450mm%100mm%344.8mm (Length % Width % Depth) 3.6 DFU 3.6.1 Overview The Duplexer Filter Unit (DFU) accomplishes the following functions: z Isolating and filtering the transmitting and receiving signals for the single carrier. z Filtering the diversity receiving signals so as to suppress out-band interference. Key parts of DFU include low-pass filter, duplexer, filter and directional coupler. 3.6.2 Structure and Principle The DFU structure is shown in Figure 3-6. ND-SUB SDN-Type SMA-TypeLPFDUPLEXERCOUPLERNSSDDDDTX-TESTTX/RXM-ANTRXM-TESTPf-OUTPr-OUTTXRXM-OUTLPFLPFDRXD-OUT NTX/RXD-ANTSRXD-TESTBPF LPF: Low Pass Filter BPF: Band Pass Filter Figure 3-6 Structure of DFU

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-13 I. Filter The filter on the transmitting channel filters transmitting signal. The filter on the main/diversity receive channel filters main/diversity receive signals respectively. Then it sends them to low noise amplifier in the RLDU for amplification. II. Duplexer The duplexer is used to isolate transmitting and receiving signals, suppress transmission spurious and reduce antenna quantity. III. Directional coupler The directional coupler couples forward/reverse power for RLDU, and monitors the antenna VSWR. 3.6.3 External Interfaces DFU is a module shared by the transmit and receive paths of the BTS. Therefore, it has interfaces with other modules in both the transmit and receive paths. Its external interfaces include a set of 8W8 D-type combination blind mate connectors on the backside, and a set of N connectors and SMA connectors on the front side. The interface signals include: z The signals between DFU and BHPA, which are transferred through the blind mate connectors on the backside. z BTS transmitting signals, which are transferred to the cabinet-bottom antenna interface through the RF cable connected with the N-connector at the front side of the module. z BTS receiving signals, which are transferred from the cabinet-bottom antenna interface to DFU for filtering through the RF cable connected with the N-connector on the front side of the module. z BTS receiving signals output from the duplexer and diversity receive filter. They are sent to RLDU via the blind mate connector on the backside. z Forward/reverse coupled RF signals, which are sent to RLDU via the blind mate connectors on the backside. z Forward/reverse coupled test signals, which are output through the standard SMA connector on the front side. 3.6.4 Indices z Supported frequency band: 450MHz z Module dimensions: 450mm%100mm%344.8mm (Length % Width % Depth)

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-14 3.7 DDU 3.7.1 Overview The Dual Duplexer Unit (DDU) implements the following functions: z Isolation and low-pass filtering of two receiving and transmitting signals. z Providing two DC feeds to T-type Tower Mounted Amplifier (TMA). z Voltage Standing Wave Ratio (VSWR) test on transmit channels in both forward and backward directions. z Coupling test of transmitting and receiving signals. Key components within DDU include low-pass filter, duplexer, directional coupler, and BIAS T (DC supply unit for TMA) which is optional. 3.7.2 Structure and Principle There are two types of DDU, type A with the BIAS T, type B without the BIAS T. Type A can be selected to feeder DC to the TMA which may be used when the BTS operates at 1900MHz band. The DDU (with the BIAS T) structure is shown in Figure 3-7. ND-SUB SDN-Type SMA-TypeLPF DUPLEXERCOUPLERNSSDDDDTX2-TESTTX/RXD-ANTRXD-TESTPf2-OUTPr2-OUTTX2RXD-OUTLPFLPFDUPLEXERCOUPLER NSSDDDDTX1-TESTTX/RXM-ANTRXM-TESTPf1-OUTPr1-OUTTX1RXM-OUTLPFBIAS TBIAS TBIAS TBIAS T LPF: Low-pass Filter Figure 3-7 Structure of DDU

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-15 I. Low-pass filter The low-pass filter is used to suppress the high-order harmonic wave. The low-pass filter on receive channel also functions to suppress the interference from the transmit channel. II. Duplexer The duplexer is used to isolate both transmitting and receiving signals, suppress spurious emission and save antennae. III. Directional coupler The bi-directional coupler couples forward and reverse power for RLDU, and monitors the antenna VSWR. IV. DC supply unit for TMA (BIAS T) If the BTS is applied to 1900MHz band, a TMA may be used. The BIAS T of the DDU is to combine and divide RF signals and DC feed so as to provide the TMA with DC. 3.7.3 External Interfaces The DDU is a module shared by both the transmitting and receiving paths of the BTS. It provides interfaces with other modules both in the transmitting and receiving paths. Its external interfaces include a set of 8W8 DB combination blind mate connectors on the back, and a set of N-connectors and the SMA connectors in the front. The interface signals include: z Signals between transmit input port and the BHPA interface. They are transmitted through the blind mate connectors on the back. z Transmitting signals, which are transmitted to the cabinet-bottom antenna port through the RF cable connected with the N-connector in front of the DDU. z Receiving input signals, which are transmitted from the cabinet-bottom antenna port through the RF cable connected with the N-connector in front of the DDU. z Signals output from the receive filter. They are sent to the RLDU via the blind mate connector on the back. z Transmitting forward and reverse coupled RF signals, which are sent to the RLDU via the blind mate connector on the back. z Transmitting and receiving coupled test signals, which are outputted through the standard SMA connector in front of the DDU. 3.7.4 Indices z Supported band: 800MHz, and 1900MHz

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-16 z Module dimensions: 450mm%100mm%344.8mm (Length%Width%Depth) 3.8 RLDU 3.8.1 Overview The Receive LNA Distribution Unit (RLDU) consists of Low Noise Amplifier (LNA), distribution unit, configuration switch and alarm monitoring circuit. Its main functions are: z Low noise amplification and distribution for BTS main/diversity receiving signals. z Built-in electronic RF switch supporting multiple BTS configurations (3 sectors or 6 sectors). z Antenna VSWR monitoring and alarming, BTS forward RF power detecting, LNA running status monitoring and alarming. 3.8.2 Structure and Principle The RLDU structure is shown in Figure 3-8. VSWR check processingVSWR and powercheckLNAmoduleSwitch distributionmoduleDC-INPWRS/WDB15RXAM-TESTRXBM-TESTRXBD-INRXBM-INRXAD-INRXAM-INAPf-INAPr-INBPf-INBPr-INRXAM1RXAM2RXAD1RXAD2RXAM3/RXBM1RXAM4/RXBM2RXAD3/RXBD1RXAD4/RXBD2Power supplyForward power output Figure 3-8 Structure of RLDU

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-17 I. Receiving signal low noise amplification and distribution unit There are 4 LNAs and distributors inside the RLDU, which process 4 signals. The 4 LNAs have the same specifications such as gain, noise factor and dynamic to ensure the balance among 4 receive paths. II. Configuration switch unit The electronic switches inside the RLDU are designed for supporting different BTS configurations. When the BTS is configured in the 3-sector mode, the electronic switches can be set to make the RLDU operate in the single-sector mode that has two main/diversity receiving paths (Each path provides 1-in-4 output to support 1~4 carriers configuration for each sector). When the BTS is configured in the 6-sector mode, the electronic switches can be set to make the LDU operate in the 2-sector mode. And each sector provides 4 main/diversity receive paths (Each path provides 1-in-2 output, supporting 1~2 carriers configuration in each sector). III. Antenna VSWR and LNA status monitoring unit The transmitted forward/reverse power coupling signals from the CDU or the DFU or the DDU are processed in the antenna VSWR monitoring circuit inside the RLDU. When the VSWR of transmitting antenna exceeds a specified threshold, alarm will occur. At the same time, the RLDU also converts transmit coupling power signal into DC level signal through its RF power detecting circuits. Through this DC level signal, any exception of transmit signal power of antenna can be monitored in realtime. LNA status monitoring circuit monitors the voltage and current of the 4 LNAs inside the RLDU. It generates alarm when fault t is found. 3.8.3 External Interfaces RLDU is the reverse link function module of the BTS, which interfaces with CDU/DFU and BTRM in both input and output sides through the two sets of 8W8 D-type combination blind mate connectors on the back of the module. Interface signals between the RLDU and the CDU/DFU/DDU are: z Main/diversity path receiving RF signals outputted from two CDU/DFU/DDU receive filters. They are amplified and distributed by the RLDU. z The CDU/DFU/DDU coupling RF signals, which are used for antenna VSWR monitoring and forward power detection. Interface signals between the RLDU and the BTRM are: z Main/diversity path receiving RF signals transmitted to the BTRM after being amplified and distributed.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-18 z Antenna VSWR, the LNA status monitoring alarm signals and forward power detection voltage signals, which are outputted to the BRCM by the RLDU through a DB15 interface in front of the module and transmitted to the BIFM for processing. The +24V DC power is necessary for the RLDU. It is provided directly by the secondary power supply module in the BTS through a MOLEX power connector in front of the module. 3.8.4 Indices z Supported frequency band: 450MHz band, 800MHz band, and 1900MHz band z Power supply: +24VDC z Power consumption: <50W z Module dimensions: 450mm%180mm%50mm (Length%Width%Depth) 3.9 BRFM The BTS RF Fan Module (BRFM) mainly consists of the BBFM, the BBFL and fans. The following is the introduction to the BBFM and the BBFL. 3.9.1 BBFM I. Overview The BTS BTRM FAN Monitor (BBFM) collects and analyzes the temperature information of BHPA module and adjusts the fan speed in realtime to lower the system noise, so as to prolong equipment service life and improve the external performance of the overall system on the premise that the system works in a safe thermal status. The Pulse Wide Modulation (PWM) control signal regarding the fan speed can be generated by the MCU of the local board or configured by the control unit of the BTRM module. At the same time, the BBFM reports to the BCKM the gain decrease, over-temperature, over-excited alarm and fan failure alarm of the BHPA to ensure the reliability of the BHPA module. Specifically, it functions to: z Control fan speed, monitor and report fan alarm. z Monitor and report the BHPA alarm. z Drive fan monitor indicator module. z Collect temperature information of the BHPA module. z Communicate with the BTRM module. II. Structure and principle The position of the BBFM in the BHPA module is as shown in Figure 3-9.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-19 Fan coverBHPABBFMBlind mateconnector Figure 3-9 Position of BBFM in BHPA module The structure of the BBFM is shown in Figure 3-10. MCUCommunicationinterfaceWatchdogHPAUInterfacecircuitPWMModulationcircuitPanel indicatordriving alarmsignal isolationcircuitTemperaturecollection Serial portBBFMBHPAExternaltemperaturecollectionFan coverBTRM Figure 3-10 Structure of BBFM module z MCU module The MCU module implements the following functions: - Collect and analyze the temperature information to generate PWM signals for controlling the fan speed. - Receive alarm signals generated by the BHPA module and fan alarm signals and report to the BTRM module. - Generate panel indicator signal. - Communicate with the BTRM module. z BHPA interface module

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-20 This module isolates and drives the interface with the BHPA. z Temperature information collection module This module collects the temperature information of the BHPA module in real time, which is implemented by the MCU in query mode. z Panel indicator driving and alarm signal isolation module This module is used to drive the panel indicator and isolate fan alarm signals. z Communication module The communication module performs serial communication with the BTRM module. z Power supply module The input power of the BFMM is +24V, and power consumption is 3.5W (excluding power for the fans). III. External interfaces z BHPA interface Interface with the BHPA module, used for the BHPA alarm monitoring. z Serial communication interface Interface used to report the alarm of the fans and the BHPA module. z Interface with the fan cover Including fan alarm signal, panel indicator, and fan power interface. IV. Indices Module dimensions: 200.0mm%55.0mm (Length%Width). 3.9.2 BBFL I. Overview The BTS BTRM FAN Lamp Module (BBFL) has three RUN indicators to indicate the running status of the BTRM module, fans and the BHPA module. The board is connected with the BBFM via the fan cover interface. It is an auxiliary board. II. Structure and principle The structure of the BBFL is shown in Figure 3-11.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 3 Radio Frequency Subsystem 3-21 Fan cover port (connect to BBFM)BHPA indicatorFAN indicatorBTRM indicatorLED1 LED2 LED3Fan 2 interfaceFan 1 interface Figure 3-11 Structure of BBFL module The BBFL consists of the following parts: z Fan 1 interface module It is a 4pin ordinary socket connector connected with the Fan 1, including power supply input port and fan alarm output port. z Fan 2 interface module It is a 4pin ordinary socket connector connected with the Fan 2, including power supply input port and fan alarm output port. z Fan cover port interface module It is connected with the fan cover of the BBFM. III. Panel indicators LED1: BTRM operating signal LED2: Fan operating signal LED3: BHPA operating signal IV. Indices BBFL dimensions: 55.0mm%25.0mm (Length%Width).

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-1 Chapter 4 Antenna & Feeder Subsystem 4.1 Overview The BTS antenna & feeder subsystem consists of two parts: the RF antenna & feeder, and the satellite (GPS/GLONASS) synchronization antenna & feeder. The former transmits the modulated RF signals and receives MS signals, while the latter provides precise synchronization for the CDMA system. 4.2 RF Antenna & Feeder The RF antenna & feeder of the BTS is composed of antenna, jumper from antenna to feeder, feeder, and the jumper from feeder to cabinet-bottom, as shown in Figure 4-1. SectorαSectorβAntennaFeederJumperJumperBTS cabinetSectorγ Figure 4-1 Structure of RF antenna & feeder 4.2.1 Antenna Antenna is the end point of transmitting and start point of receiving. The type, gain, coverage pattern and front-to-rear ratio of the antenna all will affect the system performance. The network designer should select antenna properly based on the subscriber number and system coverage.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-2 I. Antenna gain Antenna gain is the capability of the antenna to radiate the input power in specific directions. Normally, in the direction where the radiation intensity of the antenna is the strongest, the higher the gain is, the stronger the field intensity will be in a faraway place and the larger the effective coverage area will be. But there may be blind areas in the vicinity. II. Antenna pattern Antenna pattern describes the radiation intensity of the antenna in all directions. The horizontal antenna pattern is often used. It is also used as a standard to classify the antennae The BTS antenna is categorized in two types: omni antenna and directional antenna. The directional antenna includes the following types: 120°, 90°, 65° and 33°. III. Polarization Polarization is used to describe the change path of the direction of the electric field. The mobile communication system often uses uni-polarization antennas. Bi-polarization antennae have been used recently. It is an antenna with two cross-over antenna polarization directions. The isolation is above 30dB for both the +45o and -45o antennae. The adoption of the bi-polarization antenna can save antennae, as one bi-polarization antenna can replace two sets of independent uni-polarization antennae. Normally bi-polarization directional antenna is used in directional cell. Compared with the uni-polarization directional antenna, the bi-polarization directional antenna is cost-effective, space saving and easy to install. However, uni-polarization omni antenna is still adopted in omni cell. IV. Diversity technology Electrical wave propagation in urban area has the following features: z Field intensity value changes slowly with places and time. It changes in the rule of logarithmic normal distribution, which is called the slow attenuation. z Field intensity transient value attenuates selectively due to the multi-path transmission. The attenuation rules falls into Rayleigh distribution, which is called the fast attenuation. The fast attenuation, slow attenuation, multi-path effect, and shadow effect will impair the quality of communication or even interrupts the conversation. Diversity technology is one of the most effective technologies to tackle the attenuation problem. Diversity receiving and combining technology can be used to minimize the attenuation when there is little correlation between the two attenuated signals.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-3 There are polarized diversity and space diversity. In the present mobile communication system, horizontal space diversity and polarized diversity are both supported. Space diversity is effective when the distance between two antennae is over 10 wavelengths. Polarized diversity facilitates antenna installation and saves space, therefore it is used more and more extensively. V. Antenna isolation The receiving/transmitting antenna must be installed with sufficient isolation to minimize the effect on the receiver. The isolation space is subject to the spuriousness of the transmitter and the characteristics of the receiver. 4.2.2 Feeder Normally, the standard 7/8 inch or 5/4 inch feeders are used to connect the antenna and cabinet. In the site installation, 7/16 DIN connectors should be prepared based on the actual length of feeders. Three grounding cable clips for lightning protection should be applied at the tower top (or building roof), feeder middle, and the end close to the cabinet-bottom. If the feeder is excessively long, additional cable clips should be applied evenly in the middle. Since 7/8 inch and 5/4 inch feeders should not be bent, the tower top (or building roof) antenna and the feeder, cabinet and the feeder should be connected via jumpers. The jumpers provided by Huawei are 1/2 inch, 3.5m long, and with 7/16DIN connectors. The attenuation of the feeder often used is listed in Table 4-1. Table 4-1 Attenuation (dB/100m) of the feeder (ambient temperature 20°C) Frequency Band 7/8 inch feeder 5/4 inch feeder 450MHz 2.65dB 1.87dB 800MHz 3.9dB 2.8dB 1900MHz 5.9dB 4.51dB Standard conditions: VSWR 1.0, ambient temperature 20°C (68°F). 4.2.3 Lightning Arrester (Optional) When the BTS3612A works at the 1900MHz band, the lightning arrester is necessary, but for other bands, it is not necessary. The lightning arrester is used to prevent damage of lightning current to the antenna & feeder system.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-4 Usually, there are two types of lightning arresters. The first type uses the microwave principle to conduct the low frequency lightning current to the ground so as to sink the current. The second one is a discharging tube, when the voltages at both ends of the discharging tube reach a certain value, the tube conducts to sink the large current. The second technique is used in BTS3612A. Lightning arrester should be installed close to the BTS cabinet. 4.2.4 Tower-top Amplifier (Optional) When the BTS3612A works at 1900MHz band, the tower-top amplifier (TA) is optional, for the other bands, it is not necessary. The TA is a low-noise amplification module installed on the tower. It is to amplify the reverse signal from MS before the transmission loss occurs along the feeder. This helps improve the receiving sensibility of the BTS system and the reverse coverage of the system while lowering the transmitting power of MS and improving the conversation quality. Usually the triplex TA is configured. It is installed close to the antenna. This type of TA consists of triplex filter, low-noise amplifier and feeder. The triplex filter is actually the combination of two duplex filters. The signal from the antenna is first filtered off the external interference at the triplex filter, and then is amplified by the low-noise amplifier, and finally sent to the feeder. Features of the TA include: z The noise factor of TA is very low. z The TA has a wide dynamic range, which is full adaptable to the change of strength of signal received by antenna caused by different distances between the MS and the BTS. z The TA has the alarm bypass function. z The TA is fed with feeder, so it has the feeding detection device. z The TA adopts strict water-proof sealing and is adaptable to a wide range of working temperatures (-40ÿC~70ÿC). z The TA can sustain strong lightning strikes. 4.3 Satellite Synchronization Antenna & Feeder 4.3.1 Overview Many important features of the CDMA system are closely related to and much dependent on the global satellite navigation system. If the global satellite navigation system stops working for a long time, the whole CDMA network will collapse.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-5 In consideration of system security and reliability, the BTS receives signals of the GPS system or of the GLONASS system through a satellite synchronization antenna & feeder, to implement radio synchronization. In this way, the whole network can still operate normally without any adverse effect when the GPS or GLONASS system is not available. A satellite synchronization antenna & feeder system is composed of an antenna, the jumper from antenna to feeder, feeders, a lightning arrester and the jumper from feeder to cabinet-bottom (the feeders and jumpers can be configured as needed). Figure 4-2 shows the structure. BTS cabinetAntennaFeederJumperJumperLightning arrester Figure 4-2 Structure of satellite synchronization antenna & feeder  Note: When the length of the feeder is within 100m, use the 1/2” feeder, which can be directly connected to the antenna and lightning arrester without any jumper. When the length of the feeder exceeds 100m, use the 7/8” feeder. In this case, a jumper is needed. Generally, one BTS is configured with one set of satellite synchronization antenna & feeder. However, if two BCKM boards are configured to further enhance the reliability of the system, the two BCKMs each should be configured with one set of independent satellite synchronization antenna & feeder. In Figure 4-2, two satellite synchronization antenna & feeder interfaces are provided. The following describes the application of the GPS and the GLONASS in a CDMA BTS.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-6 I. GPS The GPS is a high precision all-weather satellite navigation system based on radio communications. It can provide high precision information about 3D-position, speed and time. The 3D-position is accurate to less than 10 yards (approx. 9.1m) in space; the time is accurate to less than 100ns in time. The GPS signals can be received and used as the reference frequency. The whole system consists of three parts: space part, land control part and user part. The space part is a group of satellites (altogether 24) 20,183 kilometers high, orbiting the earth at a speed of 12 hours/circle. The land control part consists of a main control center and some widely distributed stations. The user part includes GPS receivers and their supporting equipment. II. GLONASS The GLONASS is a global satellite navigation system developed by the former Soviet Union and inherited by Russia. With 24 satellites distributed on 3 orbits, it has a structure similar to the GPS, but a smaller coverage. III. Application of GPS and GLONASS in CDMA BTS The BTS3612A supports GPS/GLONASS satellite system synchronization mode, providing two synchronization solutions (GPS or GPS/GLONASS) as required by the user. In the CDMA2000 1X system, the BTS is a user of the GPS or GLONASS, utilizing their timing function. BTS3612A adopts smart software phase-lock and holdover technologies to minimize interference such as signal wander and jitter caused by ionosphere and troposphere errors of GPS or GLONASS satellites. The timing signal of the GPS or GLONASS features high reliability and long-term frequency stability. BTS3612A is equipped with a crystal clock that promises high stability. The short-term stability of this crystal clock and the long-term stability of the GPS or GLONASS combine to ensure the reliability and stability of the CDMA2000 1X system clock.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-7 4.3.2 Antenna I. GPS antenna The GPS antenna is an active antenna. L1 band (1565~1585MHz) GPS signals received by the antenna are filtered by a narrow-band filter and amplified by a preamplifier. Then they are sent to a GPS receiver integrated in the BCKM. II. GPS/GLONASS dual-satellite antenna The GPS/GLONASS dual-satellite antenna is also an active antenna. It receives both L1 GPS and GLONASS signals (1602~1611MHz). 4.3.3 Feeder Normally, standard 1/2 inch or 7/8 inch feeders are used to connect the antenna and the cabinet. In site installation, 7/16DIN connectors should be prepared based on the actual length of feeders. Three grounding cable clips for lightning protection should be applied at the tower top (or building roof), feeder middle, and the end close to the cabinet-bottom. If the feeder is excessively long, additional cable clips are needed. Since the 7/8 inch feeder should not be bent, the tower top (or building roof) antenna and the feeder, the cabinet and the feeder should be connected via jumpers. The jumpers provided by Huawei are 1/2 inch, 3.5m long, with 7/16DIN connectors. The feeder is mainly used to transmit GPS/GLONASS signals received by the GPS/GLONASS antenna to the GPS/GLONASS receiver. It also provides power for the antenna module to make pre-amplification. 4.3.4 Lightning Arrester Like the lightning arrester of RF antenna & feeder, the satellite uses the lightning arrester of antenna & feeder to protect the equipment from direct lightning stroke or inductive lightning. One feeder is configured with one lightning arrester. 4.3.5 Receiver I. GPS receiver There are many types of GPS receivers. The following introduces the one with 8 parallel paths.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 4 Antenna & Feeder Subsystem 4-8 This kind of GPS receiver is capable of tracking 8 satellites concurrently. It receives GPS signals of band L1 and tracks C/A codes. Inside the receiver, the RF signal processor makes frequency down-conversion to the GPS signals received by the antenna to get the Intermediate Frequency (IF) signals. The IF signals are then converted to digital signals and sent to 8-path code and carrier correlator, where signal detection, code correlation, carrier tracking and filtering are performed. The processed signal is synchronized and sent to the positioning Micro Processing Unit (MPU), which controls the operational mode and decoding of the GPS receiver, processes satellite data, measures pseudo-distance and pseudo-distance increment so as to figure out the position, speed and time. The receiver should be powered with regulated 5V DC and the sensitivity of the receiver is -137dBm. II. Dual-satellite receiver The principle of the dual-satellite receiver is similar to the GPS receiver. It has 20 receiving paths and can be upgraded from GPS L1 to GPS/GLONASS L1+L2 or other solutions.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-1 Chapter 5 Power & Environment Monitoring Subsystem 5.1 Overview The functional structure of the power & environment monitoring subsystem is shown in Figure 5-1. PMUACdistributionunitEnvironmentmonitor andsensorsBattery subrack/cabinet+24VDCRS485RS485DCdistributionunit-48VDC220V ACor110V ACBoolean v alueAnalog v alue BCKMBasebandboards and RFmodulesPSUAC/DCPSUDC/DCTransmission equipmentHeatexchanger fanLamp-48VDCAir conditioner/heat exchanger Figure 5-1 Functional structure of the power & environment monitoring subsystem The subsystem provides functions of power distribution and environment monitoring (including temperature control). The power distribution part includes the AC distribution unit, PSUAD/DC, the DC distribution unit, PSUDC/DC, PMU, and the battery subrack or cabinet. The environment monitoring part includes the PMU and the air conditioner or heat exchanger. The following sections describe the working principles of power distribution and environment monitoring. As the PMU mainly implements the monitoring functions, it will be introduced in Section 5.3, "Environment Monitoring"

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-2 5.2 Power Distribution 5.2.1 AC Distribution The BTS3612A supports four types of AC power supplies: three-phase 220V AC, single-phase 220V AC, three-phase 110V AC and single-phase 110V AC. I. Distribution of three-phase 220V AC The three-phase 220V AC passes through the lightning protector and the ElectroMagnetic Interference (EMI) filter before reaching the AC distribution unit. From the AC distribution unit, the power is distributed to the voltage regulator, PCUAC/DC and power sockets (reserved). Each distribution path is protected with an air switch at the input end. Detailed distribution paths are shown in Figure 5-2. Lightning arrester220VACAir switchANBNCN63A63AVoltage regulator Air conditioner/heat exchanger32APSUAC/DCReserved10AAC distribution unitA,NB,N +24V DCNAC,N +24V DCPSUEMI filterAC/DCCB Figure 5-2 Distribution of three-phase 220V AC The air switch, lightning protector and EMI filter are all installed in the power lightning protector/filter box. II. Distribution of single-phase 220V AC If the single-phase 220V AC is used for the BTS3612A, a wiring terminal for phase conversion should be equipped before the air switch to convert the single-phase power into three-phase power. The power distribution in the cabinet is the same as that of the three-phase 200V AC, as illustrated in Figure 5-3.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-3 Lightning arrester220VACAir switchANBNCN63A63AVoltage regulator Air conditioner/heat exchanger32APSUAC/DCReserved10AAC distribution unitA,NB,N +24V DCNLC,N +24V DCPSUEMI filterAC/DC Figure 5-3 Distribution of single-phase 220V AC III. Distribution of three-phase 110V AC If the single-phase 110V AC is used for the BTS3612A, an air conditioner (or heat exchanger) and a PCUAC/DC that support 110V AC should be configured. The rest configuration is the same with the distribution of three-phase 220V AC. IV. Distribution of single-phase 110V AC If the single-phase 110V AC is used for the BTS3612A, a wiring terminal for phase conversion should be equipped before the air switch to convert the single-phase power into three-phase power. The rest configuration is the same with the distribution of three-phase 110V AC. 5.2.2 DC Distribution I. Distribution of –48V DC Figure 5-4 illustrates how the 220V AC is converted into –48V DC and then distributed. The 220V AC is output by the AC distribution unit to the 220V AC power input busbar on the backplane of the PSUAC/DC subrack. The PSUAC/DC converts the power and outputs multiple –48V DC supplies to the busbar.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-4 PSU PSU PSU220V ACInput busbarOutput busbar-48V DCDC distribution busbarPMU.....AC distribution unit Figure 5-4 AC-DC conversion and distribution of –48V DC Then the DC distribution busbar sends the –48V DC to the power consumption units such as the PSUDC/DC subrack, batteries, transmission equipment, fans, lighting equipment, and the internal and external circulation fans in the heat exchanger. II. Distribution of +24V DC Figure 5-5 illustrates how the –48V DC is converted into +24V DC and then distributed. The -48V DC is output to the -48V DC power input busbar on the backplane of the PSUDC/DC subrack. The PSUDC/DC converts the power and outputs multiple +24V DC supplies to the output busbar. Then the power is sent to the distribution busbar of the DC distribution box on the top of the cabinet along the cables in the cabling trough. Wiring terminals-48VINGNDDC/DCDC/DCDC/DCPSUDC/DC subrackSwitch boxDU BTRM0PGNDRLDU1BTRM59 service processing units RLDU0...... Figure 5-5 DC-DC conversion and distribution of +24V DC

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-5 To ensure the normal power supply to other power consumption units when the power to one of the unit is disconnected due to over current, a separate over-current protection unit is equipped in the distribution box for each power consumption unit. Through these protection units, the busbar distributes the power to the terminals on the back panel, which will supply the power to various consumption units. 5.2.3 Power Distribution Devices I. PSUAC/DC The PSUAC/DC is composed of an AC-DC converter and a power monitor. The former converts the ~220V AC (local mains) into –48V DC; the later detects status of the PSUAC/DC and reports alarms. II. PSUDC/DC The PSUDC/DC is composed of a Direct Current - Direct Current (DC-DC) converter and a power monitor. The former converts the –48V DC into +24V DC; the later detects status of the PSUDC/DC and reports alarms. III. Batteries  Note: Batteries are optional. When the local mains supply fails, batteries can maintain the normal operation of the BTS for a period of time. A built-in battery subrack and an auxiliary battery cabinet are available to satisfy different requirements. z Built-in battery subrack The built-in battery subrack is configured in the auxiliary cabinet. It can be installed with four 12V/65Ah storage batteries to maintain the normal operation of the BTS2612A in S(1/1/1) configuration for more than 30 minutes. z Auxiliary battery cabinet The auxiliary battery cabinet can hold up to twenty-four 2V/650Ah or 2V/300Ah or 2V/200Ah batteries to power the system for a longer period after the mains failure. An auxiliary battery cabinet fully configured with twenty-four 2V/650Ah batteries can support the normal operation of BTS3612A in S(1/1/1) configuration for more than eight hours.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-6 5.3 Environment Monitoring 5.3.1 Structure of Monitoring System As an outdoor BTS, the BTS3612A provides comprehensive power & environment monitoring functions, which are implemented through sensors, TCU and PMU. The temperature inside the cabinet is controlled by an independent temperature control device. The monitoring system is shown in Figure 5-6. SmokesensorDoor statussensorTempsensorWatersensorPower control & batterymanagementEnvironmentmonitoring PMU7 reservedboolean valueAir switchfusedetectorPSU220/110VACPSUCurrentmeasurementTempmeasurementProtectorBatteryTo BCKM ofbasebandsubsystem-48V BusbarRS485TCUTemperaturecontrol Figure 5-6 Monitoring system of BTS3612A I. Monitoring functions of PMU The PMU monitors on a real-time basis control value signals, Boolean value signals, current/voltage analog signals and environment value analog signals. Control value signals include: z Equal floating charge and current-limiting control of batteries z Protective load connect/disconnect of batteries Boolean value signals include: z Air conditioner / heat exchanger failure alarm.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-7 z AC lightening arrester alarm. z Battery interface lightening arrester of battery cabinet. z Cabinet smoke alarms, water alarms, and door control alarms. Current/voltage analog signals include: z Current of the battery group (A) z Total load current (A) z Busbar AC voltage (V) Environment value analog signals include: z Temperature (oC) inside the cabinet (with sensors) z Humidity (RH%) inside the cabinet (with sensors) Power system management: z PSU failure and PSU protection alarm. z The communications (between the PSU and the PMU) failure alarm. z Mains available or unavailable alarm. z Mains over voltage or under voltage alarm. z DC over voltage or under voltage alarm. z Fuse status value of the batteries (-0.3VDC<Normal voltage difference<0.3VDC). II. Temperature control The BTS3612A is an outdoor BTS with a sealed structure. When it operates in a high-temperature environment, the heat generated by the devices may quickly raise the temperature inside the cabinet. To keep the temperature inside within a normal range in the extreme (either high or low) temperature environment, an air conditioner or heat exchanger can be installed in the cabinet. The equipped air conditioner or the heat exchanger itself is highly reliable and able to report alarms when faults occur. 5.3.2 Monitoring Devices I. Sensors Sensors are installed inside the BTS3612A cabinet and the auxiliary battery cabinet. The BTS3612A cabinet is equipped with temperature sensor, door status sensor, water sensor and smoke sensor, while the auxiliary battery cabinet is only equipped with temperature sensor and door status sensor. II. TCU The TCU supervises the temperature of the main equipment. When the temperature is too high or too low, the TCU will cut off the 220V AC input and the –48V DC output from the batteries, and shut down some boards to protect the main equipment.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 5 Power & Environment Monitoring Subsystem 5-8 III. PMU The PMU is the core of the monitoring system. It is responsible for collecting, processing and reporting all the environment variables. IV. Air conditioner The air conditioner can realize closed-loop control over the temperature inside the cabinet. When the air conditioner finds that the temperature is too low, it will start its heating plates and internal fans to heat the BTS. When the temperature is too high, the air conditioner will activate the cooling function to lower the temperature to a normal degree. V. Heat exchanger A heat exchanger can also be used instead of the air conditioner to control the temperature inside the cabinet. The heat exchanger has high/low-temperature alarm circuits. When the temperature inside the cabinet is higher than the temperature outside, it will discharge the heat through closed circulation. Compared with the air conditioner, the heat exchanger has a simpler structure with fewer components, and thus is more cost-effective.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 6 Lightning Protection and Grounding 6-1 Chapter 6 Lightning Protection and Grounding 6.1 Overview I. Lightning Protection Lightning protection system for communication equipment includes external lightning protection system and internal lightning protection system. The external lightning protection system is to protect the equipment against direct lightning stroke, including lightning receivers, lightning down-leading cables and grounding devices. The internal lightning protection system is to protect the equipment against indirect stroke, such as thunder bolt induction, reverse lightning stroke, lightning wave intrusion and other lightning strokes that might endanger human beings and the equipment. II. Equipment Grounding The purpose of equipment grounding is to provide the equipment with the capability of protecting against external electromagnetism interference and to ensure the safety of human beings and the equipment. The key of lightning protection is grounding, because a fine grounding can provide the equipment with a low-resistance lightning electricity discharging channel. 6.2 BTS Lightning Protection Principle 6.2.1 Principle and Characteristics As an outdoor BTS, the BTS3612A adopts multiple internal and external lightning protection measures. I. Measures of external lightning protection The BTS3612A adopts the equalized electric potential combining/grounding technology specified by the IEC and the ITU-T. This design ensures that no grounding electric potential difference is generated during lightning striking and thus no damage is caused to the equipment.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 6 Lightning Protection and Grounding 6-2 II. Measures of internal lightning protection The AC lightning arrester at the AC input port prevents the AC from direct lightning stroke or inductive lightning. The lightning protection index of the AC input port is 40kA. E1 lightning protection board at the E1 port of the BTS3612A protects E1 signal ports. The lightning protection index of E1 port is 5kA. The antenna and feeder lightning arrester at the feeder inlet protects the BTS against the striking current coupled into the feeder when the steel tower gets lightning stoke. The equalized electric potential connection and insulation design of the cabinet prevent the cabinet from the damage of lightning stroke. 6.2.2 Lightning Protection for AC Power The overall power supply for the BTS3612A is large, so an AC lightning arrester is used at the AC input port as the first level of lighting protection measures. This parallel lightning protection can effectively prevent the BTS3612A from the damage of lightning stroke. This protection function: z Adopts symmetric compound circuits, applicable to the power supply environment with poor electric network quality. z Adopts temperature-controlled circuit breaking technology with embedded over-current protection circuits to prevent the cabinet from the danger of fire. z Adopts full protection of both common mode and differential mode. z Adopts dual-color luminotrons to indicate the working states of the cabinet. 6.2.3 Lightning Protection for Trunk Cables The BTS3612A supports multiple transmission modes: E1 (75Ωcoaxial cables and 120Ω twisted pairs), T1 (100Ω twisted pairs), SDH and microwave transmission. E1/T1 ports are liable for lightning induction. Therefore, various lightning protection measures for E1/T1 ports are introduced in the following. The BESP is added at the trunk cable inlet for the lightning protection at E1/T1 ports of the BTS3612A. The connection is shown in Figure 6-1.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 6 Lightning Protection and Grounding 6-3 BESPBTSTransmissionequipmentBCIM75/120/100Grounding bar75/120/100 Figure 6-1 Connection to BTS via trunk cables All E1 cables achieve the lightning protection through the E1 lightning protection board. The circuits on the board can prevent the lightning current going into the cabinet through E1/T1 cables when the trunk lines get lightning stroke, and the circuits can also discharge most of the current through the electricity discharge tube when large current strikes the cabinet. 6.2.4 Lighting Protection for Antenna & Feeder Subsystem The Radio Frequency (RF) equipment of the BTS shall be placed within the protection range of the lightning rod, which is the precondition to ensure the normal performance of BTS lightning protection system. I. Lightning protection for RF antenna & feeder The lightning protection function for the antenna & feeder protects the equipment against secondary lightning attack, i.e. the inductive lightning. Inductive lightning means that the feeder receives inductive current upon a lightning attack, which may cause damage to the equipment. Inductive lightning can be prevented effectively in three ways: z The feeder is grounded at least at three points. In actual implementation, the number of grounding points depends on the length of the feeder. z For 450MHz band and 800MHz band, the RF antenna & feeder part and CDU (or DDU, DFU) are grounded through an internal path. The lightning current induced by the antenna & feeder can be directly discharged to the ground through the grounding point. In addition, the CDU (or DDU, DFU) itself features strong protection capability against lightning current, and can satisfy the normal protection requirements without extra lightning protectors.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 6 Lightning Protection and Grounding 6-4 z For 1900MHz band, when the TMA is configured, the DDU with BIAS T should be configured, the BTS provides the TMA with power supply through the DDU, so lightning arrester is needed at the feeder port of the BTS; If the TMA is not configured, the lightning arresters is also not needed. II. Lighting protection for satellite synchronization antenna & feeder The GPS/GLONASS satellite synchronization antenna & feeder is under the protection of lightning rods. Other lightning protection measures include: z Grounding of feeder at three points: In actual implementation, the number of grounding points depends on the length of the feeder. z External lightning protector: In normal condition, a lightning arrester is connected to the BTS side to avoid the possible damage to the BTS equipment caused by the lightning current induced by feeder cores. 6.3 Grounding of BTS Equipment 6.3.1 Internal Grounding of Cabinet Grounding terminals are installed at the cable outlet port, the bottom and the door of the cabinet. Busbars are installed in the main cabinet, with common grounding cables. Various equipment connects to the grounding system of the cabinet using the grounding cables. Various metal components of the BTS3612A are of high electric conductivity and no insulation paint is applied to the connection points of metal components. Cabinet frames, power distribution unit, PSU and air-conditioner regulator are all equipped with metal shells, which are reliably connected to the metal mechanical parts in the cabinet. 6.3.2 External Grounding of Cabinet A protection grounding (PGND) cable is connected from the PGND of BTS3612A to the nearest grounding copper bar of the office. 6.3.3 Grounding of AC Lightning Arrester Grounding device is installed in the vicinity of AC lighting arrester and connects the grounding cables of AC lightning arrester to the GND of the grounding device. The dual-color (yellow and green) plastic insulation copper-core conducting cables are adopted with the cross-sectional area less than 6mm2 and cable length less than 10cm.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 6 Lightning Protection and Grounding 6-5 The grounding device of the AC lightning arrester is well connected to the mechanical parts of the cabinet, and the contact resistance is less than 50mΩ. 6.3.4 Grounding of Transmission Equipment Grounding bar is installed in the vicinity of the transmission equipment. The GND cables from the transmission equipment are directly connected to the grounding bar. The dual-color (yellow and green) plastic insulation copper-core conducting cables with the cross-sectional area less than 6mm2 and cable length less than 20cm are used for the grounding cables. The grounding bar of the transmission equipment is well connected to the mechanical parts of the cabinet, and the contact resistance is less than 50mΩ. 6.3.5 Grounding of Overhead E1/T1 and HDSL Cables Metal sheath grounding clamp for dedicated E1/T1 and HDSL overhead cables shall be used for transmission lightning protection equipment. Necessary grounding measures shall be taken before the metal sheaths of E1/T1 and HDSL overhead cables are led into the Roxtec module. 6.3.6 Grounding of BTS Surge Protector The grounding cables for the antenna & feeder lightning arrester are connected to the nearest grounding bar, which is connected to the grounding system of the cabinet. The grounding cables for E1 lightning arrester and HDSL lightning arrester are grounded via the mechanical parts of the cabinet, and the length is less than 20cm.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 7 BTS Signal Flows 7-1 Chapter 7 BTS Signal Flows 7.1 Overview BTS signals include Abis traffic signal, Abis signaling message, O&M signal, clock signal, and local Man-Machine Interface (MMI) signal. These signals form various flows in the transmission from the Abis interface to the Um interface, as shown in Figure 7-1 (The flows are identified by different colors). I. Abis signal The Abis traffic signal, Abis signaling message and O&M signal are adapted and carried through Asynchronous Transfer Mode (ATM) protocols. At different interfaces, different physical links are used as ATM links. z At the Abis interface, the physical links are E1/T1 links. z Between the baseband processing boards, the physical link is cell bus. z The physical links for the IQ data exchange between the BRDM and various BCPMs are electrical Gbit Ethernet buses. z The physical links for the IQ data exchange between the BRDM and various BTRMs are optical Gbit Ethernet buses. The baseband signals (including the Abis traffic signal, Abis signaling message and O&M signal) are processed by the BTRM and converted into RF signals before the transmission. In the reverse direction, the BTRM receives RF signals and converts them into baseband signals. II. Clock signal As a synchronous system, the CDMA2000 1X requires precise clock reference for synchronization. Figure 7-1 shows satellite synchronization signals are used as clock reference. III. Local MMI signal The BTS provides an interface for local maintenance, through which users can perform operations and maintenance using MMI commands. The local MMI signal is essentially a kind of O&M signal from the local maintenance terminal (compared with the signal coming from a remote terminal through the BSC), so it will not be introduced separately.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 7 BTS Signal Flows 7-2 MMIBCKMCellBusCLKMCOMU...CellBusGbit Ethernet(Electric Interface) RLDUBHPA DDURLDUBHPARLDUBHPA DDURLDUBHPA.........Gbit Ethernet(Optical Interface)Antenna & FeederAntenna & FeederSatellite ReceiverAntenna & FeederBCPMBCPMBCPM1PPS, UTC 2S10MHz2S, 25MHzBCIM25MHz100 1.228MHzBTRMBTRMBTRMBTRMBRDMBSCBAME1/T1Abis signalingOAMAbis traffic16 1.228MHzBCPMAbis signaling signalOAM SignalAbis traffic signalRF singalClock Signal Figure 7-1 BTS signal flows

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 7 BTS Signal Flows 7-3 7.2 Abis Traffic Signal Flow The Abis traffic is carried by the Fundamental Channel (FCH), the Supplemental Channel (SCH) and the Dedicated Control Channel (DCCH). The FCH and DCCH carry voice traffic and inband signal, while the SCH carries data traffic. The Abis traffic signal flow is represented by the red continuous line in Figure 7-1. The following introduces the signals in the forward and the reverse directions respectively. I. Forward 1) The ATM cells from the BSC are carried by E1/T1 links to the BCIM. The BCIM processes the ATM cells through the IMA, and then under the control of BCKM sends the signal to the BCPM through the Cell Bus. 2) The BCPM completes channel processing. The baseband signals carrying the Abis traffic (received over the FCH, SCH and DCCH) from the BCIM are coded, interleaved, spread, modulated and multiplexed by the BCPM before being sent to the BRDM over the electrical Gbit Ethernet interface. 3) The BRDM allocates channel resources, and sends the baseband signals over the optical Gbit Ethernet interface to the BTRM. 4) The BTRM performs demultiplexing, up-conversion and wave filtering on the received baseband signals, and sends them to the BHPA. 5) The BHPA amplifies the signals and forwards them to the DDU, from where the signals will be transmitted by the antenna. II. Reverse In the reverse direction the signals are handled in the reverse order. 1) Through the main and diversity antennae, the DDU receives two CDMA signals transmitted from the MS. After being divided and amplified by the RLDU, the signals are sent to the BTRM. 2) The BTRM performs wave filtering, down-conversion and multiplexing on the main and diversity signals, and sends them to BRDM over the optical Gbit Ethernet. 3) The BRDM allocates channel resources, and sends the baseband signals over the electrical Gbit Ethernet interface to the BCPM. 4) The BCPM completes channel processing. The baseband signals carrying the Abis traffic (received over the FCH, SCH and DCCH) from the BRDM are demultiplexed, demodulated, de-interleaved and decoded by the BCPM. Then under the control of BCKM, the obtained signals are sent to the BCIM over the Cell Bus in form of ATM cells. 5) The ATM cells are processed by the BCIM through the IMA, and then sent to the BSC over the E1/T1 link.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 7 BTS Signal Flows 7-4 7.3 Abis Signaling Message Flow The Abis signaling messages are carried by the Access Channel (ACH) and the Paging Channel (PCH). These messages are refer to as outband signals (compared to the inband signals in the Abis traffic). The Abis signaling message flow is represented by the green continuous line in Figure 7-1. The following introduces the flow in the forward and the reverse directions respectively. I. Forward 1) The ATM cells from the BSC are carried by the E1/T1 link to the BCIM. The BCIM processes the ATM cells through IMA, and then under the control of the MC of the BCKM sends the signal to BCPM through the Cell Bus. 2) The BCPM completes channel processing. The baseband signals carrying the Abis signaling messages (received over the PCH) from the BCIM are coded, interleaved, spread, modulated and multiplexed by the BCPM before being sent to the BRDM over the electrical Gbit Ethernet interface. 3) The BRDM allocates channel resources, and sends the baseband signals over the optical Gbit Ethernet interface to the BTRM. 4) The BTRM performs demultiplexing, up-conversion and wave filtering on the received baseband signals, and sends them to the BHPA. 5) The BHPA amplifies the signals and forwards them to the DDU, from where the signals are transmitted by the antenna. II. Reverse In the reverse direction the signals are handled in the reverse order. 1) Through the main and diversity antennae, the DDU receives two CDMA signals transmitted from the MS. After being divided and amplified by the RLDU, the signals are sent to the BTRM. 2) The BTRM performs wave filtering, down-conversion and multiplexing on the main and diversity signals, and sends them to BRDM over the optical Gbit Ethernet. 3) The BRDM allocates channel resources, and sends the baseband signals over the electrical Gbit Ethernet interface to the BCPM. 4) The BCPM completes channel processing. The baseband signals carrying the Abis traffic (received over the ACH) from the BRDM are demultiplexed, demodulated, de-interleaved and decoded by the BCPM. Then under the control of BCKM, the obtained signals are sent to the BCIM over the Cell Bus in form of ATM cell. 5) The ATM cells are processed by the BCIM through IMA, and then sent to the BSC over the E1/T1 link.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 7 BTS Signal Flows 7-5 7.4 O&M Signal Flow The operations and maintenance over the BTS, originated either from the remote BAM or from the local maintenance terminal, are implemented by the OMU on the BCKM. The blue continuous lines in Figure 7-1 represent the O&M signal flows between the OMU and various boards in the BTS, while the blue dotted lines represent the flows between the OMU and the MC and CLK units on the BCKM. 7.5 Clock Signal Flow The BCKM receives satellite signals through the GPS/GLONASS synchronization antenna. The CLK unit processes the received signal and outputs 2S signal, 25MHz signal and 16%1.228MHz signal to the clock bus. The boards in the BTS obtain the required clock signals from the clock bus. z The BCIM gets the 25MHz clock signal from the clock bus, which will be processed by the clock unit of the BCIM to produce other desired clock signals. z The BRDM gets the 2S signal, 25MHz signal and 16%1.228MHz signal from the clock bus, which will be processed by the clock unit of the BRDM to produce other desired clock signals. z The BCPM gets the 2S signal, 25MHz signal and 16%1.228MHz signal from the clock bus, which will be processed by the clock unit of the BCPM to produce other desired clock signals. z The BTRM gets 100%1.228MHz signal from the Gbit Ethernet bus (optical interface), which will be processed by the clock unit of the BTRM to produce other desired clock signals such as 48%1.228MHz, 50%1.228MHz and 2S signals.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-1 Chapter 8 BTS Configuration This chapter details the configuration of each part of BTS based on the brief introduction to main cabinet, auxiliary cabinet, and cabinet door in Chapter 1. 8.1 Configuration Principle BTS3612A applies outdoors It is highly integrated and is equipped with the excellent protection function. To configure BTS3612A, observe the following rules that are listed in the order of precedence. z Use the trunk cables as few as possible. z Use the antennae as few as possible. z Use the cabinets as few as possible. The conformance to the above rules can facilitate the installation and expansion of BTS. 8.2 Configuration of Main Equipment 8.2.1 Configuration of Baseband Boards The baseband boards include BCIM, BCPM, BRDM and BCKM. The baseband subrack in full configuration is shown in Figure 8-1. The slots are numbered uniformly. However, the boards are numbered according to the board type. Slot No.Board No.0BC IM1BC IM2BCPM3BCPMBCKMBCKMBRDMBRDMBCPMBCPMBCPM5678910110145 0 101910114BCPM8 Figure 8-1 Baseband subrack in full configuration

$Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-2 I. BCIM BCIM has two versions: QC51BCIM and QC52BCIM. QC51BCIMsupports eight E1 links. Compared with QC51BCIM, QC52BCIM has more functions as follows: timeslot cross-connection, fractional ATM transmission, and T1 transmission functions. For the configuration of BCIM links, refer to the following typical data: z For S(1/1/1) BTS, configure one E1/T1 link. z For S(2/2/2) BTS, configure two E1/T1 links. The above data is based on CDMA2000 1X system. For IS95 system, the above quantity can be reduced by half. When the transmission resource is limited, the fractional ATM network function of QC52BCIM can be deployed to configure specific timeslot in a specific E1/T1 link to the BTS. II. BCPM At most 6 BCPMs can be configured in the baseband subrack. There are two types of BCPMs. z The processing capability of type-A BCPM is 64 reverse channels and 128 forward channels. z The processing capability of type-B BCPM is 128 reverse channels and 256 forward channels BCPMs are configured based on the channel processing capability required by the system, with consideration of BTRM quantity and board types. Typical configurations are listed in Table 8-1. The board Nos. of BCPMs are not successive. The left three are numbered as No.4, No.5, and No.8, while the right three are numbered as No.9, No.10, and No.11. Table 8-1 Configuration of BCPMs BTS configuration Number of type-A BCPM Number of type-B BCPM O(1) 1 Not recommended O(2) 2 Not recommended S(1/1/1) 2 1 S(2/2/2) 4 2 The above configurations are for CDMA2000 1X system. For 3-sector configuration, type-B BCPMs are recommended. For IS95 configuration, the quantity should be reduced by half.$

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-3 Normally, redundancy is not required. If one board fails, the system will automatically shield the faulty board. In this case, the system capacity decreases, but the service is normal. III. BRDM There are two types of BRDM, namely multi-mode BRDM and single-mode BRDM. The multi-mode BRDM is used to connect the BTRM in the cabinet, while the single-mode BRDM is used to cascade the ODU3601C. Providing 6 pairs of ports for leading out optical fibers, the multi-mode BRDM can be connected with 6 BTRMs. Providing 3 pairs of ports for leading out optical fibers, the single-mode BRDM can be connected with three ODU3601Cs in star networking. Table 8-2 Configuration of BRDM Cabinet configuration Connected with ODU3601C Configuration of BRDM Yes One multi-mode BRDM and one single-mode BRDM Single-cabinet configuration No One multi-mode BRDM Yes One multi-mode BRDM and one single-mode BRDM. The number of carrier configured for a combined cabinet does not exceed 6. Combined-cabinet configuration No Two multi-mode BRDMs IV. BCKM Normally, one BCKM is enough. For reliability purpose, two BCKMs can be used (active/standby mode). The BCKM receives GPS/GLONASS signal as clock source. When two BCKMs are configured, two sets of independent satellite synchronization antenna & feeder systems are required. 8.2.2 Configuration of RF Modules The radio modules include BTRM, BHPA, RLDU and CDU/DDU/DFU. The carrier subrack and the duplexer subrack in full configuration is shown in Figure 8-2.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-4 DFU/DDU/CDU2DFU/DDU/CDU1DFU/DDU/CDU0BHPA1BTRM1BHPA3BTRM3BHPA5BTRM5RLDU1BHPA0BTRM0BHPA2BTRM2BHPA4BTRM4RLDU0Synchronousantenna feederarrester Figure 8-2 RF modules in full configuration I. BTRM/BHPA configuration BTRM and BHPA are configured in pairs. That is, one carrier unit consists of one BTRM and one BHPA. In Figure 8-2, totally three carrier units can be configured for the upper and lower carrier subracks to provide maximum 6 sector carriers with maximum 3 sectors. The modules are numbered as shown in Figure 8-2. II. RLDU configuration RLDU is configured in the carrier subrack. In the case of full configuration, two RLDUs are present. When two sectors are configured per cabinet, that is, in the case of S(1/1) or S(2/2) configuration, one RLDU will suffice. When three sectors are configured per cabinet, that is, in the case of S(1/1/1) or S(2/2/2) configuration, two RLDUs should be configured. III. CDU/DDU/DFU configuration Either CDU, DDU or DFU all can be configured as a duplexer, For the difference between the three, see Chapter 3. In practice, one to three CDUs, DFUs, or DDUs, should be configured in a duplexer subrack.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-5 One DFU supports one sector carrier. That is, only the configuration of S(1/1) or S(1/1/1) is allowed. One DDU supports two sector carriers. That is, the configuration of S(2/2) or S(2/2/2) is allowed and there is no requirement about the carrier space. One CDU supports two sector carriers. That is, the configuration of S(2/2) or S(2/2/2) is allowed, but the space between the two sector carriers must be equal or larger than 2 carrier spaces (for 450MHz band and 800MHz band) or 3 carrier spaces (for 1900MHz band). For CDU and DDU, the corresponding BTRMs and BHPAs are configured from bottom to top and from left to right (as shown in Figure 8-2). For DFU, the corresponding BTRMs and BHPAs are configured from left to right in the RF subrack under the DFU, and only in the bottom. Based on the specific frequency of CDU, actual implementation conditions should also be considered when configuring the BTRMs and BHPAs. 8.2.3 Configuration of Power Modules The BTS3612A supports the 110V AC and 220V AC power inputs. The PSUAC/DC completes the conversion from 110V AC or 220V AC to -48V DC, while the PSUDC/DC completes the conversion from -48V DC to +24V DC. I. PSUAC/DC Two models of PSUAC/DC are available to respectively support 110V AC and 220V AC power inputs. In the case of full configuration, there are 9 PSUAC/DC modules, one of which is used as standby module. The maximum output current can reach 200A (8%25). II. PSUDC/DC In the case of full configuration, there are 3 PSUDC/DC modules, one of which is used as standby module. The maximum output current can reach 130A (2%65). 8.3 Configuration of Auxiliary Equipment 8.3.1 Batteries To ensure the normal operation of the BTS3612A in the case of local mains failure, storage batteries can be configured either in the battery subrack or in an auxiliary cabinet.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-6 I. Configuration of battery subrack The battery subrack can be installed with the batteries or DC lightning protector / DC filter. If batteries are installed, the subrack can hold a -48V/65Ah battery group containing four 12V/65Ah storage batteries connected in serial. If the battery cabinet is installed, only the DC lightning protector and the DC filter are configured in the built-in battery subrack. II. Configuration of battery cabinet The battery cabinet can hold a –48V/650Ah battery group containing twenty-four 2V/65Ah storage batteries connected in serial. If an air conditioner is used to control the temperature, a -48V/650Ah battery group can maintain the normal operation of the BTS in S(2/2/2) configuration (with nine PSUAC/DC modules and three PSUDC/DC modules) for four hours. 8.3.2 Temperature Control Device Either an air conditioner or a heat exchanger can be used for the temperature control, and the configuration principle is as below. When an air conditioner is adopted, the operational environment temperature can be -40 ~ +55oC, and when a heat exchanger is adopted, the operational environment temperature can be -40 ~ +45 oC I. Air conditioner Two models are available, respectively supporting the local mains of 110V AC and 220V AC. II. Heat exchanger Two models are available, respectively supporting the local mains of 110V AC and 220V AC. 8.3.3 Monitoring Devices Monitoring devices include the sensors, TMU and PMU. One PMU is configured in the BTS3612A, while the TMU is optional. Sensors include the temperature sensor, door status sensor, water sensor and smoke sensor.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-7 8.3.4 Transmission Equipment The transmission equipment is optional. The BTS3612A is connected to the transmission equipment through standard E1/T1 interface. Within the BTS3612A, standard space is reserved for installing microwave, HDSL or SDH transmission equipment. 8.4 Configuration of Antenna and Feeder I. RF antennaand feeder Two omni antennae should be used for omni cell. For 3-sectors and 6-sectors configuration, each sector needs one bi-polarization antenna or two uni-polarization antennae. When the BTS works in the 1900MHz band, tower-top amplifier may be applied. Because the power of tower-top amplifier is provided through the feeder, lightening arrester shall be configured for the RF antenna and feeder. When the BTS works in 450MHz band or 800MHz band, the tower-top amplifier and lightening arrester need not to be configured. II. GPS/GLONASS synchronization antenna and feeder Normally, one set of GPS/GLONASS synchronization antenna and feeder is configured for one BTS3612A. However, when two BCKMs are configured for BTS3612A for the purpose of higher system reliability, each of the two BCKMs requires one set of GPS/GLONASS synchronization antenna and feeder. If one set of the two fails, the BCKMs will be switched over and the synchronization signals will be received through the other synchronization antenna and feeder. 8.5 Networking Configuration The BTS3612A supports star networking, chain networking and tree networking, In practice, these networking modes are usually used together. The proper utilization of different networking modes can save a lot of transmission equipment with the guaranty of Quality of Service (QoS).

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-8 8.5.1 Star Networking I. Application scope Star networking is widely used, especially in the densely populated urban area. Start networking is shown in the following figure. BSCBTSBTSBTSE1E1E1 Figure 8-3 BTS star networking II. Advantage In the star networking mode, each BTS is directly connected with BSC via E1/T1 trunk line. The star networking is simple and allows convenient maintenance and engineering. Because the signals go through a few sections of links, the line is more reliable and future expansion is easier. III. Disavantage Compared with other networking modes, star networking requires the largest number of transmission lines. IV. Implementation The internal network of Huawei CDMA BSS is built on ATM platform. The logic links of Abis interface, such as traffic link and signaling link, are carried by ATM links, which is carried by E1/T1 links in IMA mode or UNI mode.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-9 8.5.2 Chain Networking I. Application scope Chain networking of the BTS is shown in Figure 8-4. It is applicable to sparsely populated stripe areas, e.g. along the highways and railways. BSC BTS BTSBTSE1 E1 E1 Figure 8-4 BTS chain networking II. Advantage The adoption of the chain networking mode can scale down the expenditure on transmission equipment, engineering construction, and lease of transmission links. III. Disavantage The signals go through more nodes in the chain networking mode, the line reliability is poor. The failure of upper-level BTS may affect the normal operation of lower-level BTS. Maximum three-level cascading is allowed. That is, the nodes cascaded should not exceed 3. IV. Implementation Chain networking is realized through the transmission trunk function of the BTS. The transmission trunk is essentially Virtual Path (VP) switching. One BTS can be configured with maximum 10 trunk links.  Note: ATM switching is divided into two types: VP switching and Virtual Channel (VC) switching. In the VP switching process, only the value of VPI is changed, while the value of VCI is transmitted transparently. In the VC switching process, values of both VPI and VCI remain unchanged. The VP is equivalent to a large channel, while the VC a small one.

Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-10 To configure a BTS trunk link, the forward/reverse BCIM No., forward/reverse link set No., and forward/reverse VP No. should be properly configured. 8.5.3 Tree Networking I. Application scope Tree networking mode applies to the area where network structure, site and subscriber distribution are complicated, such as the area where different types of subscribers are not evenly distributed. Tree networking is shown in Figure 8-5. BSCBTSBTSBTSE1E1E1BTSBTSE1E1 Figure 8-5 BTS tree networking II. Advantage In the tree networking mode, less transmission lines are needed than in the star networking mode. III. Disavantage In this mode, because signals go through many sections of links, the line reliability is low, and engineering and maintenance are difficult. The failure of upper-level BTS may affect the normal operation of lower-level BTS. Expansion is not easy and may cause substantial network reconstruction. The cascaded BTSs should not exceed 3 levels, i.e. the depth of the tree should not exceed 3 layers. IV. Implementation The tree networking is in fact one application of the chain networking. For example, the first-level BTS can be configured with multiple trunk links. These trunk links can

$Technical Manual Airbridge BTS3612A CDMA Base Station System Principle Chapter 8 BTS Configuration 8-11 be allocated to each of the lower-level BTSs. (Note that these BTSs do not share the same trunk lines.) The lower-level BTS can in turn allocate the trunk links to its own lower-level BTSs. In this way, a tree network comes into being. 8.5.4 Fractional ATM Networking I. Application scope When the transmission resource is rather limited and the BTS capacity is not large, BTS3612A supports the fractional ATM networking. That is, BTS only uses specific timeslots in one or more E1/T1 links. Fractional ATM networking is similar with the tree networking, except that in the fractional ATM networking mode, only part of the timeslots of E1/T1 links are used. II. Advantage In this mode, transmission resource can be fully and flexibly utilized and thus related cost can be reduced. III. Disavantage The capacity of BTS cannot be too large due to the restriction of transmission resource. If the actual BTS capacity is more than what the transmission resource can support, the call connected ratio will be affected. The failure of upper-level BTS may affect the normal operation of lower-level BTS. Expansion is not easy and may cause substantial network reconstruction. IV. Implementation BTS3612A can use the timeslot cross-connection function of QC52BCIM board to implement the fractional ATM networking without the support of external equipment. In practice, the timeslot cross-connection should be added to the upper-level BTS, while the E1/T1 timeslots should be specified for the lower-level BTS by adding the E1/T1 fractional ATM transmission link to this BTS. 8.5.5 Cascading with ODU3601Cs I. Application scope The ODU3601C is an outdoor soft BTS. By connecting ODU3601 to a master BTS3612A in cascading mode, flexible coverage can be realized, including the indoor coverage, underground coverage, and coverage of highways and railways.$

Huawei Technologies BTS3612A-1900 CDMA Base Station User Manual Part 3

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