M900/M1800 BTS3X Series Base Transceiver Station
The M900/M1800 BTS3X Series Base Transceiver Station (BTS) is a modular RF structure designed for flexible configuration in various base station setups. It supports GSM900, GSM1800, GSM1900, GSM850, EGSM, and RGSM frequency bands. The BTS3X series includes indoor models (BTS30, BTS312) and outdoor models (BTS3006A, BTS3012A), each with specific hardware structures and configurations.
Hardware Structure
Indoor Base Station (BTS30/BTS312):
Consists of cabinets, internal boards, cables, and an antenna system. The antenna system includes antenna, feeder, jumper, feeder window, and an optional Tower Mounted Amplifier (TMA). Boards inside the cabinet include the Timing/Transmission and Management Unit (TMU), Transceiver Unit (TRX), and Combiner and Divider Unit (CDU). Cables include fibers, E1 trunk cables, signal cables, and power cables.
Outdoor Base Station (BTS3006A/BTS3012A):
Comprises cabinets, internal boards, cables, auxiliary equipment, and an antenna system. The antenna system is mandatory and includes a BTS antenna system and an optional GPS antenna system. Auxiliary equipment may include transmission equipment, power lightning-protection filter box, AC/DC units, Transmission Supply Unit (TSU), storage battery, temperature control unit, environment monitoring unit, sensors, and air-conditioner or heat exchanger, depending on site configuration. Boards inside the cabinet are similar to indoor models, including TMU, TRX, and CDU. Cables include fibers, trunk transmission cables, signal cables, power cables, monitoring cables, alarm cables, and sensor cables.
Technical Specifications
Dimensions:
- BTS30 (indoor): 1600 mm (H) x 600 mm (W) x 450 mm (D)
- BTS312 (indoor): 1884 mm (H) x 650 mm (W) x 500 mm (D)
- BTS3006A (outdoor): 1700 mm (H) x 900 mm (W) x 720 mm (D)
- BTS3012A (outdoor): 1700 mm (H) x 1200 mm (W) x 1000 mm (D)
Weight:
- BTS30 (indoor): 180 kg (single cabinet, full configuration)
- BTS312 (indoor): 330 kg (single cabinet, full configuration)
- BTS3006A (outdoor): 390 kg (single cabinet, full configuration), 285 kg (assembly cabinet)
- BTS3012A (outdoor): 650 kg (single cabinet, full configuration, including storage battery), 420 kg (assembly cabinet)
Power Supply:
- BTS30 (indoor): 220 V AC (150 V AC–280 V AC, 47 Hz–63 Hz), -48 V DC (-40 V DC–-60 V DC), 24 V DC (19 V DC–29 V DC)
- BTS312 (indoor): 220 V AC (150 V AC–280 V AC, 47 Hz–63 Hz), -48 V DC (-40 V DC–-60 V DC), 24 V DC (19 V DC–29 V DC)
- BTS3006A (outdoor): 150 V AC–276 V AC (47 Hz–53 Hz), 300 V AC tolerant voltage or 100 V AC–127 V AC (47 Hz–63 Hz, double live lines)
- BTS3012A (outdoor): 150 V AC–276 V AC (47 Hz–53 Hz), 300 V AC tolerant voltage or 100 V AC–127 V AC (47 Hz–63 Hz, double live lines)
Power Consumption:
- BTS30: Typical 1200 W, Maximum 1800 W (single cabinet, full configuration)
- BTS312: Typical 2100 W, Maximum 3500 W (single cabinet, full configuration)
- BTS3006A: 1200 W (heat exchanger off), 1300 W (heat exchanger cools), 2900 W (heat exchanger heats) (single cabinet, full configuration)
- BTS3012A: 2200 W (air-conditioner or heat exchanger off), 3200 W (air-conditioner cools), 4800 W (air-conditioner heats), 2600 W (heat exchanger cools), 3900 W (heat exchanger heats) (single cabinet, full configuration)
Functional Subsystems and Boards
The BTS3X series is composed of several functional subsystems: Common Subsystem, Signal Processing Subsystem, and Antenna Feeder Subsystem.
Common Subsystem:
Manages the entire BTS, providing reference clock, power supply, transmission ports, maintenance ports, and external alarm collection ports.
- TMU (Timing/Transmission and Management Unit): Provides timing, transmission, and management functions. It supports multi-channel multiplexing, flexible topology modes (star, tree, chain), MMI and O&M link, software downloading, fault/configuration/performance/security management, centralized provisioning, hot backup of the clock, and external alarm input.
- BIU (BTS Port Unit): Realizes digital signal conversion to HDB3 code, timeslot exchange, clock signal extraction and output, internal bus data synchronization, and free-run clock generation. Supports up to four E1 channels and various network topologies.
- OMU (Operation and Maintenance Unit): Core control and processing unit, configures BIU and MCK parameters, receives fault alarms, and manages alarms. Stores two BTS software versions for loading.
- MCK (Main Clock Module): Provides standard 13 MHz system reference clock (OCXO) with high stability, generating SREF, FCLK, OBCLK, and FN. Supports free-run and software phase-locking modes. MCKs of two boards provide hot backup.
- EAC (External Alarm Collection Module): Collects external alarm signals and reports them to the OMU.
- TDU (Time Distribution Unit): Transfers clock signals (SREF, OBCLK, FCLK, FN) from the TMU to TRXs and other units, and transfers alarm signals.
- ASU (Access network SDH transmission Unit): Completes photoelectric conversion, provides E1 ports, and self-rate cross-connection between E1s. Supports external optical transmission ports (155 M SDH, PON). Can be configured as TM, ADM, or REG in ring, chain, or P2P topologies. Provides 64 kbit/s sub-rate crossing for the first four inter-E1s and four E1 ports with re-timing.
- PAT (Passive Transmission Board): Realizes order wire communication, far-end photoelectric conversion, data multiplexing/demultiplexing, 1 to 4 channels of 2 Mbit/s services, remote delay control, and various loopback functions (E1, 2M, near-end, far-end).
- TES (Transmission Extension power Supply unit): Provides working power (+5 V DC, -5 V DC, 75 V AC ringing current) and communication transferences for the TEU. Acts as a bridge for TEU messages to the TMU.
- ABB (Abis Bypass Board): Applied in BTS chain topology. Bypasses Abis transmission line during power failure at a middle-level site, connecting directly to downstream BTS. Can perform transmission line loopback for BSC to detect link quality.
- ABA: Aids the ABB to communicate with the TMU.
- PSU (Power Supply Unit): Provides DC power supply to the system. Supports AC/DC or DC/DC units depending on power mode. One PSU supplies two TRXs, with N+1 current equalizing hot backup.
- PMU (Power Monitor Unit): Manages power supply and collects alarms. Monitors control variable signals (float charging, current limiting, protection load switching), Boolean value signals (AC mains, over/under voltage, fan status, smoke detection, waterproof, access control, battery fuse status), and analog variable signals (battery group current, main bar voltage, internal temperature/humidity).
- FMU (Fan Monitor Unit): Manages and controls fans in the fan box for heat dissipation. Provides power supply filtering, voltage reduction, fan speed control (voltage-control mode), and monitors fan failures (stalled, short-circuited) to send alarms to the PMU.
- EMU (Environment Monitor Unit): Monitors the environment inside the cabinet and collects alarm information.
- EMUA (Environment Monitor Unit A): Monitors the environment outside the cabinet and collects alarm information.
- SPD (Surge Protection Device): Protects the power supply system from lightning.
- PWB (Power Backplane): Backplane of the common resource subrack.
Signal Processing Subsystem:
- TRX (Transceiver unit): Supports multiple frequency bands. Receives management and configuration information from TMU, reports status and alarms. Adopts a modularized structure with baseband processing unit (TBPU) and RF processing unit (RPU).
- TBPU (Transceiver Baseband Processing Unit): Includes Signaling Processing Part (SCP), Digital Signal Processor (DSP), and Carrier Unit Port Controller (CUI). Performs channel encoding/decoding, interleaving/de-interleaving, speech encryption/decryption, rate adaptation, logical/radio channel mapping, and signal up/down conversion, sampling, filtering, and amplification.
- RPU (Radio frequency Process Unit): Includes Receiver Unit (RCU), Transmitter Driver and PLL unit (TDP), and Power Amplifier Unit (PAU). Provides diversity receiving, generates local oscillations, and amplifies radio signals.
- PBU (Power Boost Unit): TRX output power amplifier for wide coverage. Increases effective transmission power of the antenna. Maximum output power 49 ± 1 dBm. Amplifies one channel output power of 40 W TRX (GSM900/GSM1800).
- CDU (Combining and Distribution Unit): Completes duplexing of reception/transmission signals, filters and combines transmission signals, filters, amplifies low noise, combines receiving signals, and feeds the TMA. Supports GSM900, GSM1800, GSM1900, GSM850. Max input power 60 W per port. Includes standing wave test, low-noise amplifier faulty alarm, TMA alarm, and power attenuation control functions.
- ECDU (Enhanced Combining and Distribution Unit): Similar functions to CDU, but supports a maximum input power of 100 W per signal port.
- EDU (Enhanced Duplexer Unit): Completes duplexing of transmission/reception signals of two TRXs, filters transmission signals, amplifies low noise, distributes receiving signals, and feeds the TMA. Designed for wide coverage and low loss. Each TRX uses an independent antenna. Max input power 100 W per port.
- MDU (Multi Combining and Distribution Unit): Provides smooth capacity expansions for TRX1 to TRX8.
- SCU (Simple Combining Unit): Completes broadband combination function, used with CDU to combine transmission signals of multiple TRXs, reducing CDU count. Max input power 60 W per single port.
- ESCU (Enhanced Simple Combining Unit): Similar functions to SCU, implements 4-in-1 combined transmission. Supports 921 MHz–960 MHz (900 MHz ESCU) and 1805 MHz–1880 MHz (1800 MHz ESCU). Max input power 100 W per single port.
Antenna Feeder Subsystem:
- Antenna: Receives and sends signals.
- Feeder: Transmits signals from antenna to cabinet, decreases transmission attenuation.
- Lightning arrester: Prevents lightning current from damaging equipment.
- TMA (Tower Mounted Amplifier): Amplifies uplink signals to enhance receiving sensitivity and coverage area, reduces MS transmission power, and improves speech quality.
Usage and Maintenance Features
DIP Switches and Jumpers:
Many boards feature DIP switches and jumpers for configuration, such as setting IP addresses, cabinet numbers, product feature numbers, ABB configuration, storage battery type, hardware version flags, clock selection, and E1 resistance settings.
- ABB: DIP switch S2 for end site/transmission terminal loopback support.
- CMB: DIP switches S1, S2, S3, S4, S5 for cabinet number and CBUS pull up/down resistors. Settings are factory-set and should not be changed unless necessary.
- FMU: DIP switch S1 for fan configuration (big/small fan frame). Factory-set.
- O2TCB: DIP switches S1-S8 for product feature number, ABB configuration, storage battery type, cabinet hardware version, CBUS1 offset, clock selection, and cabinet number. Factory-set.
- PWB: DIP switch SWK for cabinet number. Factory-set.
- TCU: DIP switch S1 for BTS clock driving enabled/disabled and CBUS1 matching setting.
- TDU: DIP switches for clock selection and basic cabinet group settings.
- ASU: DIP switches SW3, SW4 for IP address (third and fourth segments). Jumper J30 for 48/24 V feeding of board order wire. J28 for storage battery charge control (recommended short-circuiting 1-2 to retain configuration). J3 and J17 for loading programmable logic components (recommended short-circuiting 1-2).
- PAT: DIP switches S2, S3, SW6-1 to SW6-4 for board ID, E1 port grounding, and E1 resistance settings. J18 for order wire feeding voltage.
- TRB: DIP switches S1-S6 for cabinet number, frame number, and clock bus resistor settings. Settings are factory-set and should not be changed unless necessary.
Indicators:
Boards are equipped with LED indicators to display their status (power, running, alarms).
- ABB: PWR (Green: power on/off), RUN (Green: normal/abnormal operation), ALM (Red: no alarm/alarm generated).
- CDU/ECDU: POWER (Green: power on/off), VSWR1 (Yellow: Level 1 VSWR alarm), VSWR2 (Red: Level 2 VSWR alarm), TMA (Red: TMA alarm), LNA (Red: LNA alarm).
- PMU: ALM (Red: normal/system fault), RUN (Green: normal operation).
- PSU: VIN (Green: power input normal/abnormal), ALM (Red: PSU operation normal/alarm), VO (Green: power output normal/abnormal).
- TES: PWR (Green: power on/off), RUN (Green: normal/abnormal operation), ALM (Red: no alarm/alarm generated).
- ASU: RUN (Green/Yellow/Red: normal/minor alarm/major alarm), ETN (Green: network cable connected/data transmission/no network cable).
- PAT: RUN (Red: self-test/downlink communication interrupted/uplink interrupted/normal operation), LFA (Green: multi-frame out of synch/synchronized), F0n (Green: tributary status indicator).
- TCU: PWR (Green: power on/off), ALM (Red: no alarm/alarm generated).
- TMU: PWR (Green: power on/off), RUN (Green: normal/abnormal operation), LI1-LI4 (Green: E1 local/remote alarm/normal), M/S (Green: active/standby/faulty), PLL (Green: free-run/trapping/locking mode/abnormal).
- TRX: PWR (Green: power on/off), RCP (Green: SCP normal/HDLC link setup failure/abnormal), RDP (Green: DSP normal/EQDSP faulty/no configuration/clock alarm/test software running/CHDSP faulty), FAIL (Red: no alarm/alarm generated).
Ports:
Various ports are available for connectivity and testing.
- CDU/ECDU: TX/RX-ANT (N Female: RF signal), MS/TX-TEST (SMA Female: test port), TX1/TX2 (N Female: transmitting signal input), RXD-ANT (N Female: diversity receiving antenna), RXD-OUT (SMA Female: diversity receiving output), RX1-4/RX5-8 (SMA Female: RX divider output), RXM-TEST (SMA Female: main receiving test), RXD-TEST (SMA Female: diversity receiving signal test), HL-OUT/HL-IN (SMA Female: high level output/input), TX-COM (N Female: combiner output), TX-DUP (N Female: duplexer TX input), CDU-BUS (DB15: control bus), DC-IN (DC power input).
- EDU: TX/RX-ANT A/B (N: RF signal), MS/TX-TEST A/B (SMA: test port), TXA/TXB (N: transmitting signal input), RXA1/RXA2/RXB1/RXB2 (SMA: RX divider output), EDU-BUS (DB15: control bus), DC-IN (DC power input).
- ESCU: TX1-TX4 (N Female: RF input signal), TX-COM (N Female: combined RF signal output).
- MDU: TX1-TX4 (N Female: transmitting signal input), COM1-COM3 (N Female: combiner output), IN1/IN2 (N Female: combiner input), RXIN1/RXIN2 (SMA Female: RX divider input), RX1-RX8 (SMA Female: RX divider output).
- PBU: OUT (N Female: RF signal transmitting), IN (N Female: RF signal receiving), RST (reset button).
- SCU: TX1-TX4 (N Female: RF input signal), TX-COM (N Female: combined RF signal output).
- TDU: CKB1/CKB2 (DB25: clock signal), DCF1/DCF2 (DB37: data signal), EAC1/EAC2 (DB37/DB25: external alarm input), TME1 (DB37: E1 transmission signal conversion), TRA1/TRA2/TRB1/TRB2 (DB37: built-in optical transmission signal conversion).
- TMU: RST (reset button), DBG (Ethernet: debug network), T2M (SMB: 2 MHz clock output), FCK (SMB: frame clock output), T13M (SMB: 13 MHz clock output), MMI (DB9: man machine port).
- TRX: TX OUT (N Female: RF signal transmitting), RXA IN (SMA Female: main receiving), RXB IN (SMA Female: diversity receiving), RST (reset button), MMI (DB9: serial port for debugging).
TMA Feeding:
CDU and ECDU boards provide +12 V DC feeding to the TMA via internal and external conductors of "TX/RX_ANT" and "RXD_ANT" ports. Care must be taken to avoid short-circuits. TMA current strength can be controlled via knobs on the rear panels of CDU/ECDU (Type B and C) or switches (Type D and E).
Software Management:
The OMU in the TMU can store two versions of BTS software, allowing for upgrades and backups. The BSC can load new software to the OMU via the O&M Link (OML).
Clock Synchronization:
The MCK provides highly stable clock signals for the TDMA system. In combined cabinet groups, the main cabinet's MCK provides the clock for synchronous cells. The O2TCB supports clock transfer and identification of cabinet types.
Cascading and Topology:
The BTS supports various topologies including star, tree, and chain. ABB boards facilitate Abis bypass in chain topology. FMU J5 and J6 sockets are used for cascading BTS30 units.
This comprehensive set of features and specifications ensures the BTS3X series can be deployed in diverse network environments, providing robust and flexible base transceiver station functionality.
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