User Manual Part 2

(Optional) Configuring Multi-Host Systems for Manual Mode
FlexWave Prism Host, Remote and EMS 5.1 System Reference Page 171
ADCP-77-073 • Issue 2 • 11/2009 © 2009 ADC Telecommunications, Inc.
ee In the
DART Operating Mode
list, select one of the following:
•
Standby
—forces the RF function to be muted in the Host and its linked
Remote.
•
Normal
—allows the system to operate normally (RF function not forced to
be muted), assuming all other system components are in proper working
order. (Default setting.)
The mode
Undefined
is not user selectable, and indicates that the EMS is
unaware of the current mode.
ff In the
DART Diversity Status
list, select
nonDiversity
or
diversity
. For a diversity
application, one DART will be configured
nonDiversity
for the primary
FWD/REV path signal and the other DART will be configured
Diversity
. This
selection therefore determines whether the DART card being configured will
carry the primary or secondary RF path.
For dual DART configurations, such as dual-pcs, smr800/smr900 and
dual-aws, both DARTs must have
DART Diversity Status
set to
nonDiversity
.
gg In the
DART Forward Gain
list, set this value (0 to 31 dB) based upon the fully
loaded forward path signal level from the Base Station. The Host DART expects
signal levels from
-25
to
+5 dBm
. If the fully loaded signal is +5 dBm, then the
DART forward gain should be set to 0 dB, if the fully loaded signal is -25 dBm,
then the DART Forward Gain should be set to 30 dB. The equation is:
DART Forward Gain = 5 - fullyLoadedBasestationSignal.
The diversity status of the Host DART will not extend to the Remote DART connected to
it. You must ex
plicitly configure the Remote DART to have the same diversity status as
the Host DART.
If you are setting up the system when no calls are going through, you must allow
headroom for a fully
loaded forward path. For CDMA protocols, the difference from
unloaded to fully loaded is typically 8
dB, so if the unloaded signal is - 15dBm, then the
fully loaded input would be - 7 dBm and the Host For
ward Gain should be set to 5- (- 7)
= 12 dB.
The same rules applies for GSM carriers, except that the u
nloaded to loaded is
determined by the equation 10*log10(# RF Channels). So if there are 4 GSM RF Cha
nnels,
then the loaded forward path is 6 dB above unloaded.
If sufficient headroom is not present, the
n the LPA can be over- powered causing a Loss
Of Service.
When configured correctly, the Host DART Forward input can handle peaks of 14dB
above the BTS signal
level. For example, if the fully loaded CDMA carrier is - 25dBm, then
peaks up to - 11 dBm can be handl
ed (CDMA peak to average is typically 10- 12 dB). If
the peaks exceed the 14 dB of headroom, then Auto
matic Level Control (ALC) will occur
to prevent over- driving the A/D Converter.