User Manual

RBS 2101, RBS 2102, RBS 2103 RBS 2202 Radio Configurations
Radio Performance
The output power of all GSM 900 configurations is reduced by a maximum of
0.6 dB by the ddTMA.
In addition, the Bias-T decreases the performance by a maximum of 0.2 dB in
the case of P-GSM and E-GSM configurations.
In order to maintain correct RX_lev reporting from the BTS when using ddTMA
in GSM 900 configurations, the feeder loss of the selected IDB has to be
adjusted. The feeder loss value is the sum of the feeder loss minus the gain of
the ddTMA.
If the ddTMA is limited regarding band widths, the correct band width has to be
typed in through the OMT (R3+ and on) in order to maintain correct capabilities
reporting.
For 1800/1900 the following applies:
If the nominal current consumption of the ddTMA exceeds 100 mA, the alarm
limits of the ddTMA supervision have to be adjusted through the OMT (R3+
and on).
For 1800/1900 the following applies:
The gain in front of the cabinet is the sum of the gain of the ddTMA minus the
feeder loss and the loss of the external duplexer. This value is 8dB by default.
If the calculated value differs from 8dB, it has to be changed in the IDB. The
loss of the external duplexer is mas. 0.6 dB.
The following table shows the allowed gain in front of the cabinet for the different
CDU types to reach both sensitivity and to fulfil GSM recommendations.
Table 24 Allowed Gain in Front of Cabinet
GSM TypeRBS 2000 with CDU
Type
900 1800 1900
A 6–7 7.5 – 8.5 7.5 – 8.5
C 6–7 7.5 – 8.5 7.5 – 8.5
C+ 6.5–10 8–12 8–12
73 (74)
EN/LZT 720 0341 Uen R1A