Siemens BS-240 Technical Description page 49

Information
Base Station System
Antenna
VS WR
supervision
TNF TNF
ESN
Control
CAN bus
DC interf.
from
from
Tx
Tx
Base 2:1
Fig. 4.5 FICOM 8:1
A30808-X3247-L14-2-7618
Therefore, the number of base modules is equal to the number of cells the FICOM has
to support. The number of expansion modules per cell depends on the total number of
carriers per cell (2,4,6 or 8).
A FICOM Expansion module 1:1 doesn't exist any more. In case an odd number of
carriers is recommended in one cell, only one half of the expansion module 2:1 is used.
For this application, one TX port remains open.
The FICOMs are implemented for two different frequency bands: GSM-R 900 and GSM
1800.
TNF TNF
Control
CAN bus
DC interf.
from
from
Tx
Tx
Exp 2:1
DIAMCO (DI(=2) Amplifier Multi Coupler)
The DIAMCO contains two sub-modules with receive filters, low noise amplifiers and
power splitters.
For the uplink direction, the DIAMCO has to be used to filter and distribute the received
signals to the Carrier Units. With the FICOM, it is possible to combine 8 frequencies in
downlink direction (TX) in one Rack.The receive filters provide the substantial part of the
receive band filtering required by GSM 05.05, 11.21 and JTC J-STD-007.
The LNA takes care of a low system noise figure and consists of two branches. In case
of malfunction of one amplifier the RX gain of the DIAMCO decreases by about 6 dB.
The power splitter distributes the received band to the CUs (Carrier Units). A splitting
factor of 8 is implemented in order to feed 8 CUs. Additionally, the DIAMCO has a
cascade output which is used for Rack Extension.
In addition, the functionality of a PDU (Power Distribution Unit) for two TMAs is inte-
grated in the DIAMCO. This is the DC power supply and the alarm supervision of the
TMAs. Alarm monitoring is done with a signalling interface between DIAMCO and TMA,
TNF
ESN
from
from
Tx
Tx
Exp 2:1
Technical Description (TED:BSS)
TNF TNF
ESN
Control
CAN bus
DC interf.
from
Tx
Exp 2:1
BS-240/241
TNF
ESN
Control
CAN bus
DC interf.
from
Tx
49