The DBS3900 WiMAX uses a modular design. It has only two basic function modules: baseband unit (BBU) and remote radio unit (RRU). The BBU communicates with the RRU through the high-rate common public radio interface (CPRI).
The RRU is connected to the BBU by using optical fibers and to the antenna system by using feeders or jumpers.
A BBU3900 is a baseband subsystem of the DBS3900 WiMAX. It processes baseband signals and signaling, manages radio resources, and performs operation and maintenance (OM) and clock synchronization. It also provides ports for signal transmission between the base station (BS) and the access service network gateway (ASN-GW).
As the intermediate frequency (IF) and radio frequency (RF) subsystem of the DBS3900 WiMAX, a remote radio unit (RRU) implements conversion between baseband signals, IF signals, and RF signals, demodulates radio signals received, modulates signals to be transmitted, and amplifies the transmit power.
The DBS3900 WiMAX generally uses a two-port antenna or a four-port antenna.
If the RRU is connected to a two-port antenna, the BS implements the two-antenna multiple-input multiple-output (MIMO) function.
If the RRU is connected to a four-port antenna, the BS implements the four-antenna MIMO function and beamforming (BF) function.
The DBS3900 WiMAX supports the remote electrical tilt (RET) antenna. The maintenance personnel can log in to the M2000 client in the equipment room to remotely maintain and manage the RET antenna, such as automatic scanning, antenna tilt setting, and status query.
NOTE:
The LTE main processing and transmission unit (LMPT) supports both the Worldwide Interoperability for Microwave Access (WiMAX) system and the Long Term Evolution (LTE) system. The BWA main processing and transmission unit (BMPT) only supports WiMAX.
The LTE baseband processing unit (LBBPc) supports WiMAX and LTE. The BWA baseband processing and radio interface unit (BBBI) only supports WiMAX.
The FANc is required when the LBBPc is configured.
One or two Universal power and environment interface units (UPEUs) or UPEUc boards are required for a DBS3900 WiMAX.
A UPEUc is required for a DBS3900 WiMAX-LTE. Two UPEUc boards are required if three or more baseband boards are configured.
The UPEU and UPEUc cannot be installed in the same BBU.
