Technical data

612 Chapter 20
W-CDMA or W-CDMA (with HSDPA) Over Air
Interpretation of Over the Air Measurement Results
W-CDMA or W-CDMA (with HSDPA)
Over Air
Interpretation of Over the Air Measurement Results
This section contains expected result values and possible causes of error if the
expected results are not met.
Freq (Frequency)
If you are in the channel mode, verify that the correct channelization and channel
number are set.
Freq Error (Frequency Error)
The frequency error of the analyzer should be <1 kHz. If the frequency error is
greater than this, there could be a possible malfunction in the base station
equipment. Other possible explanations for Frequency Error include:
• the effects of multipath transmission
• pilot dominance
• failure of the base station to lock onto a GPS signal
Before performing a procedure to check the base station equipment, check to ensure
that the test set is performing a correct measurement. You can do this by reviewing
the frequency reference settings for the test set (refer to “Setting the Transmitter
Reference” on page 596).
Ensure that these settings are correct, and that the test set shows reference lock.
Lastly, make sure the test set has been powered on, and has been locked for at least
15 minutes.
If the error is still occurring after performing the above procedures, you will need to
check the Base Station equipment for a source of the error. You can also verify that
the base station is malfunctioning by turning off its modulation hardware and
performing a frequency measurement on the Base Station carrier signal in the
spectrum analyzer mode of the test set (refer to “Performing a Basic Spectrum
Analyzer Measurement” on page 415).
You can use the
Frequency Limits setting to make your analyzer indicate
automatically whether or not a signal has exceeded the pre-defined limits you set.
Scramble Code
If the Scramble code is not as expected, it could be due to an incorrect Base Station
setting or to incorrect positioning of the test set. Use of the “strongest pilot” display