User's Manual

Purpose of the Optimization
08/01/2001
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1X SCt4812ET Lite BTS Optimization/ATP
PRELIMINARY
Why Optimize?
Proper optimization and calibration ensures that:
S Accurate downlink RF power levels are transmitted from the site.
S Accurate uplink signal strength determinations are made by the site.
What Is Optimization?
Optimization compensates for the site-specific cabling and normal
equipment variations. Site optimization guarantees that the combined
losses of the new cables and the gain/loss characteristics and built-in
tolerances of each BTS frame do not accumulate and cause improper site
operation.
What Happens During
Optimization
Optimization identifies the accumulated loss (or gain) for each receive
and transmit path at the BTS site, and stores these values in a database.
S A receive path (RX) starts at the Duplexer Directional Coupler
(DRDC) or Transmit & Receive Dual Directional Coupler (TRDC)
antenna feedline port and travels through the DRDC/TRDC, the
Multi–coupler Preselector Card (MPC) and additional splitter
circuitry, ending at a Broad Band Transceiver (BBX) backplane slot in
the Small CDMA Channel Processor (SCCP) shelf.
S A transmit path (TX) starts at the SCCP shelf BBX backplane slot, is
routed to the Linear Power Amplifier (LPA) Trunking Module,
through the LPAs, back through the LPA Trunking Module, through
the bandpass filter or 2–cavity combiner, and ends at the
DRDC/TRDC antenna feedline port.
Six of the seven BBX2 boards in each SCCP shelf are optimized to
specific RX and TX antenna ports. The seventh BBX2 board acts in a
redundant capacity for BBX2 boards 1 through 6, and is optimized to all
antenna ports. A single value is generated for each complete path,
thereby eliminating the accumulation of error that would occur from
individually measuring and summing the gain and loss of each element
in the path.
BTS equipment factors in these values internally, leaving only
site–specific antenna feed line loss and antenna gain characteristics to be
factored in by the CFE when determining site Effective Radiated Power
(ERP) output power requirements.
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