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Chapter 4, Description of Fields
Fields
Closed Loop Pwr Cntl
This field sets the power control mode.
• Open Loop mode causes the Test Set to send an alternating sequence of up/down
power-control bits to the mobile station during periods when no other power-control
operation is being performed. For example, if the Execute field is selected while the
Test Set is in Open Loop mode, the mobile station will adjust its power according to
the sequence of power control bits entered in the Change and Steps field. As soon
as the number of power control bits entered in the Steps field have been sent, an
alternating sequence of up/down power-control bits resumes, attempting to hold the
mobile station’s power level at the value the mobile station was driven to by the
Change and Steps fields.
NOTE: Make sure that the Test Set power level is not reduced to a level where the mobile station
receives bad frames when using Open Loop power control mode. If the mobile station receives
a bad frame, it will assume the power control bit was a down bit and reduce its power by 1 dB.
When the power control mode is Open Loop, the alternating sequence of power control bits
will attempt to hold the mobile station’s power level at the reduced power level. As more bad
frames are received, the mobile station can continue to lower its power level until the call is
eventually dropped.
See "Drop Timer" on page 238
.
• Off disables the power control subchannel.
• Closed Loop sends power control bits to the mobile station in an attempt to drive
the mobile station’s power level to a set-point based on the power transmitted from the
Test Set and the open loop estimate.
• Always Up forces the power control subchannel to send continuous “up” power
control bits (0’s).
• Always Down forces the power control subchannel to send continuous “down” bits.
(1’s).
GPIB Example
“DISP CTXR;CDMA:PCONtrol:MODE ‘Open Loop’”
selects Open Loop power control mode.
Operating Considerations for Closed Loop Pwr Cntl
The power control operations performed when the Execute field is selected, such
as “n up” or “ramp” take precedence over the power control bit sequence expected
when a mode, such as “always up” is selected. For example, if the choice in the
Change field is “n down” and the power control mode is “Always Up”, the
number of “down” power control bits entered in the Steps field will be sent when
the Execute field is selected. The Test Set will then resume sending continuous
“up” power control bits.