User's Manual

mBSC2500U-005-RUCM11
MBSC2500U-005-RUCM11 April 15, 2013
Page 57
5.4 System Tuning
5.4.1 BTS Signal Conditioning
The interface from the operator BTS equipment to the MBSC2500-005-RUCM11 is via simplex RF
connections to the BIU. The nominal downlink input to the BIU (TXin) is 0 dBm±1dB (range: -10dBm to
+10dBm). If the BTS signal downlink exceeds +10 dBm, or the signal is a composite duplex RF signal, then
RF signal conditioning will be required.
BTI provides a high-power Point of Interface to perform RF signal conditioning (mBSC-C-POI) The use and
operation of this component is outside the scope of this document.
5.4.2 Set Downlink Gain
It may be necessary to adjust the Downlink gain of the mBSC-C system in order to achieve a balanced
forward and reverse link, or to adjust for other conditions (input levels from the BTS, propagation
characteristics at different bands, specific RF design). The MBSC2500-005-RUCM11 provides two points of
adjustment for downlink gain:
1. Software controlled attenuator for each band in the BIU
2. Software controlled attenuator in each band-specific Remote Unit
The determination of appropriate values for these parameters is outside the scope of this document.
5.4.2.1 Adjust BIU Downlink Attenuator
Adjust the BIU downlink value for each frequency band as follows:
1. Click on the BIU in the topology diagram and the component window will pops up on the right as
shown in Figure 47 - BIU Attenuator.
2. Downlink Attenuation Value (XXX MHz):
Input the appropriate value for each frequency band (0dB –
25dB range)
3. Click Save
Note that the system will report an error message if the input value is out of range.