Technical data

220 Chapter 8
CDMA Over Air
Using the CDMA Over Air Tool
CDMA Over Air
Using the CDMA Over Air Tool
CDMA over air measurements provide a quick method of verifying CDMA
transmitter performance. These transmitter measurements can be made on a base
station from the convenience of your vehicle without taking the base station out of
service. Over air measurements are especially useful in maintaining hard-to-access
cell sites such as pole top base stations. Option 210 - cdmaOne/CDMA2000 OTA
may also be used to measure signals at a coupled port on the transmitter.
For out-of-service CDMA transmitter measurements, Option 2000 - cdmaOne /
CDMA 2000 Analyzer is recommended. For more information refer to “CDMA
Analyzer” on page 181.
CAUTION To achieve valid over-the-air measurements, the test set must be stationary (not
moving). An alternative is to make these measurements from a coupled port at the
base station.
Preparing to Make CDMA Over Air Measurements
An important consideration when making CDMA over air measurements is your
location relative to the base station. There must be no obstructions between your
location and the base station antennas. Also, the GPS antenna must be able to “see”
the satellites to obtain lock. Using internal GPS for the time reference has the same
advantages mentioned for CDMA Tx Analyzer measurements (“island cell”
detection).
You must know the channel or frequency and the PN offset of the CDMA signal to
be analyzed. Each base station sector has a unique PN offset. For more information
on PN offsets refer to the “Metrics Provided by CDMA Over Air Measurements” on
page 252.
Once you have connected the proper antenna to the test set, chosen a stationary
location, and verified that you have a clear view of the base station antennas, you
can perform CDMA over air measurements.
If this is the first CDMA over air measurement for this base station, you must find a
location that meets the criteria for making a valid measurement. Your location must
have a dominant pilot and very low multipath power. If you have made CDMA over
air measurements at this location before and know it provides valid measurements,
skip to “Performing a Basic CDMA Over Air Measurement” on page 222.