Ericsson RBS 2106 Reference Manual page 117

Distribution Switch Unit (DXU-21)
The DXU is the central control unit for the RBS. It supports the
interface to the BSC, and it collects and transmits the alarms. The DXU
controls the power and climate equipment for the RBS. It has a
removable compact flashcard which makes it possible to replace a faulty
DXU without the need for loading RBS software from the BSC.
The DXU is also provided with four connections for transmission lines.
It can handle both 2 Mbit (E1) and 1.5 Mbit (T1) PCM links.
The DXU has hardware support for EDGE on 12 TRXs.
Double Transceiver Unit (dTRU)
RBS 2206 has capacity for a maximum of six dTRUs. The dTRU
contains two TRXes for transmission and reception of two radio carriers.
It has a built-in combiner with the optional possibility of combining two
TX signals into one TX output. It is also prepared for four-branch RX
diversity for further improvements in sensitivity.
One version of the dTRU imports only GMSK and the other version
supports both GMSK and EDGE.
Combining and Distribution Unit (CDU)
The CDU is the interface between the transceivers and the antenna
system. All signals are filtered before transmission and after reception
by means of bandpass filters. The CDU allows several dTRUs to share
antennas. There are a maximum of three CDUs in one RBS 2206.
The task of the CDU is to combine transmitted signals from several
transceivers, and to distribute received signal to several transceivers.
The CDU is hardware-prepared to support EDGE.
Two different CDU types are used in RBS 2206 to support all the
configurations.
CDU-F is a filter combiner intended for high capacity solutions. It can
handle up to four transceivers on two antennas. One-, two- and three-
sector configurations are possible in one cabinet with only two antennas
per sector. A combination of three CDU-Fs can handle 12 transceivers
on two antennas.
CDU-G can be configured either for high capacity or for high coverage.
It is a combiner that can be used for synthesizer hopping.
To achieve capacity, CDU-G is used in a configuration where the
hybrid combiner in the dTRU is used. Up to two dTRUs (four
transceivers) can be connected to two antennas. One-, two- and
three-sector configurations are supported.
To achieve maximum coverage, CDU-G is used in a configuration
where the hybrid combiner within the dTRU is not used. Only one
dTRU can be connected to each antenna. The number of dTRUs in an
RBS 2206 cabinet is limited to three in this case.
EN/LZT 720 0008 P2A
2001-11-28
© Ericsson Radio Systems AB
— All Rights Reserved —
Product Data RBS 2206
115 (485)