Bts 3900a Product Description 5u1o63

System Structure of the BTS3900A The BTS3900A consists of the following modules: *The BBU3900 is used for baseband processing and enables interaction between the BTS and the BSC. *The DRFU, the double-transceiver filter unit, performs modulation and demodulation between baseband signals and RF signals, processes data, and combines and divides signals. *The power distribution box and RF cabinet provides space for BBU3900 and DRFU and the functions of power distribution, heat dissipation, and surge protection.

Structure of the BTS3900A Cabinet The BTS3900A cabinet consists of the RF cabinet and the APM30 power cabinet. The RF cabinet is categorized into two types: 3RFU cabinet and 6RFU cabinet. For the BTS3900A, the APM30 battery cabinet and APM30 transmission cabinet are optional. The battery cabinet provides longtime backup power, and the transmission cabinet can accommodate the transmission equipment of the . The components of the BTS3900A include the DRFU, BBU, DCDU-02, FMUA, FAN unit, and GATM, among which the GATM is optional. Figure 2-1 shows the typical configuration of a BTS3900A cabinet that consists of a 6RFU cabinet and an APM30 power cabinet.

Logical Structure of the BTS3900A Logical Structure of the BTS3900A This describes the logical structure of the BTS3900A. It mainly consists of the BBU and DRFUs. The logical structure of the BTS3900A consists of the RF subsystem, control subsystem, power subsystem, and antenna subsystem. Figure 2-5 shows the logical structure of the BTS3900A. The logical subsystems of the BTS3900A are as follows: *RF subsystem whose functions are implemented by the DRFU *Control subsystem whose functions are implemented by the BBU *Power subsystem whose functions are implemented by the following modules: – PDU – Power Subrack (AC/DC) – DCDU-02 – DCDU-03A – Battery *Antenna subsystem whose functions are implemented by the following modules: – GATM – TMA – Antennas

Software Structure of the BTS The BTS software consists of the platform software, signaling protocol software, OM software, and data center. The latter three are application software, and the platform software provides for the application software. Figure 2-6 shows the software structure of the BTS. Platform Software The platform software provides for the signaling protocol software, OM software, and data center. The functions of the platform software are as follows: *Timing management *Task management *Memory management *Module management *Managing the loading and running of the application software *Providing the message forwarding mechanism between modules *Tracing massages between modules to facilitate troubleshooting

Signaling Protocol Software The functions of the signaling protocol software are as follows: *Processing the radio network layer protocol *Processing the transport network layer protocol, which performs transport data configuration, ALCAP processing, and SAAL processing

*Managing the internal logical resources (such as cells and channels) of the BTS and the mapping between physical resources and logical resources OM Software The OM software works together with the maintenance terminals such as the LMT to maintain the BTS. The functions of the OM software are as follows: *Equipment management *Data configuration *Performance management *Commissioning management *Alarm management *Software management *Tracing management *Security management *Backup management *Log management Data Center The data center stores the configuration data of all the modules.

Power Distribution Modes of the BTS3900A The BTS3900A allows the 220 V AC input. The description of the power distribution is as follows: *When the external 220 V AC is used, the PDU leads the 220 V AC into the PSU (AC/DC) in the power subrack (AC/DC). The PSU converts the 220 V AC to -48 V DC, and then transmits the converted DC back to the PDU. *The PDU distributes the -48 V DC. Part of the -48 V DC is directly distributed to certain modules. Part of the -48 V DC is distributed to the DCDU-02. The DCDU-02 then distributes the -48 V DC to certain modules. *When the APM30 transmission cabinet is configured, the PDU leads the -48 V DC to the DCDU-03A in the transmission cabinet. The DCDU03A then distributes the -48 V DC to certain modules. *The power subrack (AC/DC) performs the charging and discharging of the batteries.

This describes the monitoring system of the BTS3900A. The monitoring system monitors the power, fans, and environment. *The BBU can provides up to two RS485 bus ports and 16 Boolean inputs. *The modules on the RS485 bus 0 cannot substitute those on the RS485 bus 1. *If two MPUs with the same DIP switch setting are configured, they cannot be installed on the same bus.

Components of the Monitoring System Table 4-1 Monitoring signals of the BTS3900A Unit Address FMUA (mandatory) bus0 GATM2 (optional) bus0 PMU (mandatory) bus1 AFMU (mandatory) bus1 GATM1 (optional) bus1 FMUA (optional) bus1

Functions of the Monitoring System

Table 4-2 Functions of the Monitoring System

Unit

Control

FAN

*Fan failure monitoring *Adjust the fan speed *Temperature and fan speed monitoring

GATM

Reports the RET control alarm signals.

EMUA

*Communicates with the central processing unit through the two RS485 ports *Input voltage monitoring *Provides independent 12 V DC/24 V DC temperature and humidity sensor ports. *Provides Boolean input signal monitoring ports, and connects to the Boolean monitoring signals in dry mode or OC mode. *Provides six external Boolean output control ports in relay node mode.

PMU

*Communicates with the central processing unit through the RS232/RS422 serial port. *Manages the power system and charging and discharging of batteries. *It reports water alarms, smokes alarms, door control alarms, standby Boolean alarms, ambient humidity and temperature, battery temperature, and standby analog values. *Power distribution monitoring and alarm Reporting

DCDU-02

Provides the monitoring of surge protection failure

FMUA

*Collecting environment alarm information in the cabinet. The environment alarm is classified into temperature alarm, humidity alarm, smoke alarm, water immersion alarm, and door status alarm. *Collects surge protection alarm information of the DC power distribution unit. *Monitors the operating status of fans. The fan speed can be adjusted based on the temperature or adjusted by the central processing unit. *Stops the rotation of the fans when the ambient temperature is low. *Temperature monitoring and reporting *RS485 port cascading and extension *The FMUAs can be cascaded.

Reference Clocks of the BTS3900/BTS3900A The BTS3900/BTS3900A s three types of reference clocks: line clock, BITS clock, and free-run clock. Line Clock The BBU3900 directly extracts clock signals from the E1/T1 interface. Then, the BBU exports the precise 2 MHz and 8 kHz clocks after frequency dividing, phase locking, and phase adjusting. The 2 MHz and 8 kHz clocks are used for frame synchronization and bit synchronization in the BTS3900/BTS3900A. BITS Clock The BBU3900 s the BITS clock mode by providing a port for the 2.048 MHz BITS clock. Free-Run Clock When the external reference clocks are unavailable, the oven controlled crystal oscillator (OCXO) on the GTMU of the BBU3900 provides the 13 MHz clock to ensure the normal operation of the BTS.

Signal Flow of the BTS3900/BTS3900A The signal flow of the BTS3900/BTS3900A consists of the traffic signal flow and the signaling flow of the BTS. The BTS3900/BTS3900A signal flow is classified into the DL traffic signal flow, UL traffic signal flow, and signaling flow. DL Traffic Signal Flow The DL traffic signal flow is transmitted from the BSC to the MS through the BTS3900/ BTS3900A. In the BTS3900/BTS3900A, the BBU and DRFUs work together to process the DL traffic signals. Figure 6-1 shows the DL traffic signal flow of the BTS3900/BTS3900A. The DL traffic signal flow is as follows: 1. The BSC sends E1 signals to the BBU through E1 or optical cables. 2. After receiving the E1 signals, the BBU processes the E1 signals as follows: (1) Extracts clock signals from the E1 signals (2) Configures the BTS system based on the data configuration on the OML (3) Encapsulates the E1 data in the format of the RI frame, and then transmits the data to the DRFU through the RI signal cable 3. After receiving the signals, the DRFU processes the signals as follows:

(1) Decapsulates the high-speed RI frames to obtain the baseband signals (2) Transmits the baseband signals to the relevant operation units for encapsulation and interleaving (3) Converts the digital signals into the analog signals and modulates the analog signals into RF signals (4) Combines or divides the RF signals based on its own configuration (5) Transmits the combined or divided signals to the antenna subsystem

UL Traffic Signal Flow Opposite to the DL traffic signal flow, the UL traffic signal flow is transmitted from the MS to the BSC through the BTS3900/BTS3900A. In the BTS3900/BTS3900A, the BBU and DRFUs work together to process the UL traffic signals. Figure 6-2 shows the UL traffic signal flow. The UL traffic signal flow is as follows: 1. The antenna receives the signals sent from the MS. If the TMA is configured, the received signals are amplified by the TMA and then transmitted to the DRFU through the feeder. 2. After receiving the UL signals, the DRFU processes the signals as follows: (1) Divides the UL signals received from the antenna, Rx1 in, or Rx2 in (2) Converts the divided analog signals into the digital signals to obtain the baseband signals (3) Transmits the baseband signals to the relevant operation units for decryption and de-interleaving (4) Encapsulates the processed data in the format of the RI frame, and then transmits the data to the BBU through the RI signal cable 3. After receiving the signals, the BBU processes the signals as follows: (1) Decapsulates the high-speed RI frames to obtain the baseband signals (2) Encapsulates the baseband signals in the format of the E1 frame, and then transmits the signals to the BSC through the E1 cable or the optical cable

Signaling Flow This describes the BTS3900/BTS3900A signaling flow on the Abis interface. The BBU serves as the control unit and works with DRFU to process the signaling. Figure 6-3 shows the signaling flow The signaling flow is as follows: 1. The signaling data received from the BSC is transmitted to the BBU through the Abis interface. 2. The BBU encapsulates the signaling data in the format of the RI frame, and then transmits the signaling data to the DRFU through the RI signal cable. 3. The DRFU decapsulates the RI signals into the baseband signals, transmits the baseband signals to the relevant operation units for processing. 4. The BBU encapsulates the data of its own status in the format of the RI frame, and then transmits the data to the DRFU through the RI signal cable. 5. The BBU decapsulates the received RI signals to obtain the baseband signals. 6. The BBU obtains the status of the BTS by analyzing the baseband signals. Then, the BBU transmits the information on the BTS status to the BSC through the Abis interface.

Configuration Principles of the BTS3900/BTS3900A

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The BTS3900/BTS3900A uses DRFU transceiver module and DRFU built-in duplexer. A single cabinet provides up to 12 TRXs with the maximum cell configuration of S4/4/4 and s the dual-band application. In the BTS3900/BTS3900A, the antenna subsystem, DRFUs, and BBU need to be configured. Basic Configuration Principles Smooth upgrade of configuration. If multiple types of hardware configurations meet the requirements for configuring the parameters in network planning, the configuration mode that implements the smooth upgrade is preferred. The BTS3900/BTS3900A solution is recommended in S4/4/4 cell configuration or lower configurations. When multiple antennas are permitted, the BTS3900/BTS3900A solution can be applied in S8/8/8 and S4/4/4+S4/4/4 dualband cell configurations. Wide coverage. The DRFU s wide coverage. The DRFU can work in PBT, transmit diversity, or 4-way receive diversity mode in configurations lower than S2.

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Antenna Configuration Principles One antenna can serve up to two DRFUs to the S4/4/4 configuration. By default, the receive diversity is adopted in the GSM. That is, two feeder (two single antennas or one dual-polarized antenna) must be configured in a cell. When one internal combination is allowed, the cell configuration of S4 and lower configurations use a single antenna, the configurations of S5 to S8 use a double antenna, and the configurations of S8 to S12 use a triple antenna. Each sector of the BTS must be configured with the minimum number of antennas. For the 2-antenna receive diversity, each sector has two antenna channels; for the 4-antenna receive diversity, each sector has four antenna channels.

RF Configuration Principles Table 8-1 RF configuration principles of the BTS3900/BTS3900A

RF Configuration Principles Principle

Table 8-1 RF configuration principles of the BTS3900/BTS3900A

Configuration principles of the DRFU ports

Configuration principles of a single cabinet

Description  ANT1 and ANT2 are the TX ports of the duplexer. They are connected to jumpers.  Rx1 in, Rx1 out, Rx2 in, and Rx2 out are used for the interconnection between the DRFU modules. When the two TRXs provided by the DRFU belong to the same cell, both Rx1 in and Rx2 in can be the input ports for receive diversity of the two TRXs. When the two TRXs provided by the DRFU belong to different cells, Rx1 in is the input port for RX diversity of TRX 1; Rx2 in is the input port for receive diversity of TRX 2.  RI_0 and RI_1 are= the ports for high speed signal cables. They are connected to RI ports on the BBU.

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Example In the S3/3 configuration, three DRFUs need to be configured. The TRXs provided by the middle DRFU belong to different cells. Then, the Rx1 in port on the middle DRFU is the input port, which belongs to the first cell, for receive diversity of TRX 1. The input port for RX main diversity of TRX 2 is ANT1. The Rx2 in port is the input port, which belongs to the second cell, for receive diversity of TRX 2. The input port for RX main diversity of TRX 2 is ANT2.

Star topology is adopted between the BBU None and DRFUs. The DRFUs and the high-speed interfaces on the BBU have a one-to-one mapping relationship. That is, if DRFU slot 1 is idle, RI port 1 on the BBU is also idle. A single cabinet s the maximum cell configuration of S4/4/4.

Principle Configuration principles of multiple cabinets

Description *When star and ring topologies are adopted between the BBU and DRFUs, three levels of DRFUs in a ring can be connected to one BBU. That is, one BBU s 3 x 3 = 9 DRFUs. *When star and chain topologies are adopted between the BBU and DRFUs, three levels of DRFUs on a chain can be connected to one BBU. That is, one BBU s 6 x 3 = 18 DRFUs.

Example None

Non-combination in the transmit channel

*The non-combination configuration is recommended for the DRFU to avoid the power loss in combination and to reduce the power consumption of the BTS. *If combination is required, the cavity combiner must be configured outside the DRFU and one combination is recommended.

None

Configuring two TRXs in one sector

A single DRFU does not the S1/1 application; however, three DRFUs the S3/3 application. *When the DRFU works in transmit PBT, transmit diversity, or 4-way receive diversity mode, a DRFU provides only one TRX. Therefore, the actual configuration does not involve the mode of configuring two TRXs in one sector.

For example, for a site in S5/4/7 cell configuration, nine DRFUs are installed meeting the requirements of S6/4/8 cell configuration but data is still configured in S5/4/7 cell configuration.

Principle

Description

Example

Number of DRFUs

*When the number of TRXs of the site is less than 12, an odd number of TRXs can be configured for a cell. Number of DRFUs = round up [(Number of TRXs + Number of S1 cells) ÷ 2] *When the number of TRXs of the site is greater than 12, two TRXs should be configured for a cell. Number of DRFUs = round up (Number of TRXs after two TRXs are configured in one sector ÷ 2)

l S3/3/3: Number of DRFUs = round up (9 ÷ 2) = 5; S1/2/3: Number of DRFUs = round up [(6 + 1) ÷ 2] = 4. l After two TRXs are configured in one sector, the S5/5/5 configuration is S6/6/6. Number of DRFUs = (6 + 6 + 6) ÷ 2 = 9.

TRX allocation in double antenna mode

After TRX allocation, the cells with the odd number of TRXs are adjacent cells. *S5 = S3 + S2 or S5 = S2 + S3 *S6 = S4 + S2 or S6 = S3 + S3 *S7 = S4 + S3 or S7 = S3 + S4 *S8 = S4 + S4

*In S3/5/4, S5 can be divided into S3 + S2. Then, the cell configuration is S3/(3/2)/ 4. *In S2/5/5, the first S5 is divided into S2 + S3; the second S5 is divided into S3 + S2. Then, the cell configuration is S2/(2/3)/ (3/2).

Principle

Description

Example

Configuring double TRXs in a site

*If the number of DRFUs is less than or equal to 6 in a double-TRX site, the two TRXs are configured in the same cabinet. If the number of DRFUs of the two bands is less than 3, the 900 MHz DRFUs are installed in the 3 slots on the left, and the 1800 MHz DRFUs are installed in the 3 slots on the right. *When two RF cabinets are configured and the number of DRFUs of each band is less than 6, the 900 MHz DRFUs are installed in the first cabinet and the 1800 MHz DRFUs are installed in the second cabinet. The DRFUs are installed in the slots according to the typical S4/4/4 configuration. When two RF cabinets are configured and the number of DRFUs of one band is greater than 6, the band with fewer DRFUs shares the cabinet with the other band. Mixed configuration of DRFUs are not allowed.

None

Configuration Principles of the BBU One BBU provides six RI ports. In the chain topology, a single BBU can up to 36 TRXs. Figure 8-1 shows the BBU slots.

Board or Module

Description

BSBC

1 pcs must be configured.

UBFA

1 pcs must be configured.

UPEU

*1 pcs must be configured. *1 pcs can be configured when the backup power is required. The UPEU, however, cannot be configured with the UEIU at the same time.

UEIU

*1 pcs must be configured when three or more than three BTS3900 cabinets are configured. *In the outdoor application, 1 pcs must be configured when two or more than two APM30 power cabinets are configured.

GTMU

*1 pcs must be configured. *The GTMU occupies slot 5 and slot 6.

UELP

*Not required in the BTS3900 *1 pcs must be configured in the BTS3900A. The UELP occupies slot 0.