ADC Telecommunications Inc. F0684-112 Manual Do Utilizador

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CONFIDENTIAL
Connecting a Main Hub to a Base Station
6.8
Connecting a Main Hub to a Base Station
The Fusion Wideband system supports up to three RF sources: one for Band 1, one 
for Band 2 and one for Band 3. This section explains how each band can be connected 
to its associated base station.
Each Fusion Main Hub band has separate system gain parameters. For example, Band 
1 can be set for +5 dB of downlink system gain while Band 2 can have +15 dB of 
downlink system gain. Thus, each band can be configured as a separate system to 
allow for full integration to its associated base station.
When connecting each of the Fusion Wideband Main Hub bands to its base station, 
the following equipment may be required: circulators, filter diplexers, directional 
couplers, combiner/splitters, attenuators, coax cables, and connectors. In addition, use 
the following considerations to achieve optimal performance:
1.
The downlink power from the base stations must be attenuated enough so that the 
power radiated by the RAU does not exceed the maximum power per carrier listed 
in Section 6.3, “Maximum Output Power per Carrier,” on page 6-4.
2.
The uplink attenuation should be small enough that the sensitivity of the overall 
system is limited by Fusion Wideband, not by the attenuator. However, some base 
stations trigger alarms if the noise or signal levels are too high. In this case the 
attenuation must be large enough to prevent this from happening.
CAUTION:The 
UPLINK
 and 
DOWNLINK
 ports cannot handle a DC power 
feed from a BTS. If DC power is present, a DC block must be used or the 
Fusion Wideband Main Hub may be damaged.
If, in an area covered by Fusion Wideband, a mobile phone indicates good signal 
strength but consistently has difficulty completing calls, it is possible that the attenua-
tion between Fusion Wideband and the base station needs to be adjusted. In other 
words, it is possible that if the uplink is over-attenuated, the downlink power will pro-
vide good coverage, but the uplink coverage distance will be small.
When there is an excessive amount of loss between the Fusion Wideband Main Hub 
uplink and its associated band’s base station, the uplink system gain can be increased 
to as much as 15 dB to prevent a reduction in the overall system sensitivity.
6.8.1
Uplink Attenuation
The attenuation between the Main Hub’s uplink port and the associated band’s base 
station reduces both the noise level and the desired signals out of Fusion Wideband. 
Setting the attenuation on the uplink is a trade-off between keeping the noise and 
maximum signal levels transmitted from Fusion Wideband to the base station 
receiver low while not reducing the SNR (signal-to-noise ratio) of the path from the