Introduction to Base Transceiver Station (BTS) and Its Cards

Introduction to Base Transceiver Station (BTS) and Its CardsLAB # 6

Engr. Mehran MamonaiAppearance of BTS3012 CabinetLike a server cabinet

The BTS3012 cabinet is purple gray in color and vertical in appearance

Physical Structure of the BTS3012The components are

Transmission subrackCommon subrackDTRU subrack -0Fan subrackDTRU subrack-1DAFU subrack Power distribution unit Signal lightning protection subrack

Transmission sub-racklocated below the common sub-rack.Reserves space for the baseband unit (BBU). Such as SDH,microwave transmission equipment

Common subrackCommon subrackThe common subrack is installed below the fan subrack. It holds the following parts:DTMU DEMU DATU DCSU DCCU DABB DPTU

DTMUDual Transmission or Timing Management Unit an entity for basic transmission and control in the BTS3012.It works as a main controller.The DTMU is a mandatory module inserted in slots 0 and 1 (from left to right)DTMU (cont.)

BIUConnects the BTS and the BSC Synchronizes the lower-level and the upper-level clock MCUSupports the UART and HDLC communication protocols Controls the BIU to establish the communication between the BSC and the BTS Provides the platform for the running of the MCK software modules MCKHigh precision clock source required by the BTS and the system clock based on this clock source Judges the status of the phase-lock, provides software phase-lock and DA adjustment, and generates the frame numbers Transmits clock signals and synchronization signals between the active and the standby DTMUs 8DEMUDual Environment Monitoring UnitThe DEMU performs the following functions:Monitors the environment information sent from the smoke sensor, water sensor, temperature and humidity sensor, infrared sensor, and door control sensor Collects alarm information and reports it to the DTMU DATUDual Antenna and TMA Control Unit

Controls the RET antenna Feeds power to the TMA

TMA= Tower Mounted Amplifier 10DCSUCombined cabinet Signal connection Unit is placed in slot 5 of the common sub-rackThe DCSU is a mandatory boardThe DCSU performs the following functions:Transmits clock signals, data signals, and control signals between the main cabinet and the extension cabinet Transmits the clock signals, data signals, and control signals from the DTMU to the DTRU

DCCUCable Connection Unit is placed in slot 6.The DCCU is a mandatory board.The DCCU performs the following functions:Transfers E1 signals Transfers the control signals for the fans Transfers the clock signals from the DAFU subrack

DPTUPacket transmission unit can be installed in slot 3 or 4The DPTU is mandatoryThe DPTU performs the following functions:Provides the interface for Abis over IP Provides the BTS with the convergence function of a Hub Provides the functionality of Clock Over IP

DTRU subrackThe DTRU subracks can hold up to nine DTRUs

DTRUDouble-Transceiver Unit (DTRU) is placed in the double-transceiver subsystem of the BTS. One DTRU consists of two TRXsBaseband Processing PartThe baseband processing part performs the following functions:Processing signaling, coding and decoding, interleaving and de-interleaving, modulation and demodulation Supports RF loop test and switchover of the faulty phase-locked loop Amplifying output power

DTRU (cont.)RF Transmitting PartThe transmitting part of the RF signals performs the following functions:Modulates the baseband signals into RF signals and performs up-conversion, filtering, and RF hopping Amplifies and outputs the RF signals RF Receiving PartThe receiving part of the RF signals performs the following functions:Demodulates the RF signals into baseband signals and performs RF hopping Divides the received RF signals and performs receive diversity

Fan subrackThe fan subrack holds one fan boxa fan monitoring board consists of four fans.The fan monitoring board detects the temperature at air inlets at bottom of the cabinet and automatically adjusts the fan speed

DAFU subrack Antenna Front-end UnitThe DAFU subrack can be configured withDDPUDCOMDFCU or DFCB.

DDPUDual-Duplexer Unit The DDPU performs the following functions:Provides lightning protection through the ANT port Detect VSWR alarms in the antenna system Control the gains for the receive low noise amplifier Transmits multiple routes of RF signals from the transmitter to the antenna

DCOMCombining UnitThe DCOM combines two routes of TX signals from the DTRU, and then sends them to the DDPUPower Distribution UnitThe power distribution unit consists of the DC lightning arrester,EMI filter,PGND bar,Busbar terminal socket (top)Busbar (right)Lightning protection subrackThe signal lightning protection subrack is installed on top of the cabinet. It is configured with the following boards:DMLC DELC DSAC

DMLCMonitor Signal Lightning-Protection Card The DMLC performs the following functions:Provides lightning protection for Boolean input and output signals Provides lightning protection for analog signals that are transmitted from the smoke sensor, water sensor, door control sensor, infrared sensor, humidity and temperature sensor

DELCE1 Signal Lightning-Protection Card The DELC performs the following functions:Provides lighting protection for E1 signals

DSACSignal Access Card

The DSAC performs the following functions:Provides six Boolean alarm inputs Provides lightning protection for BITS clock signals