
360 Chapter 15
W-CDMA Uplink Digital Modulation for Receiver Test
Understanding the PRACH
In this example the data part power will be 40 dB higher than the control part power. Since
the Pp-m is set to 0 dB, this means that the control part power level is equivalent to the
preamble power. This condition will create a substantially higher message part power
compared to the preamble power, and in most cases, this would cause the carrier power to
readjust itself to compensate for the high message part power.
Example 3:
In this example the control part power is 10 dB less than the preamble power and the data
part power is
−23.52 dB (beta of 1) less than the control part power. These settings result in a
message part power that is less than the preamble power.
Power Control Modes
The ESG gives you the opportunity to control your PRACH power using one of two methods, a
Pp-m mode or a Total mode. The mode selection is accomplished using the
PRACH Power Setup
Mode Pp-m Total
softkey.
Pp-m Power Mode
The Pp-m mode lets you control the message part power by making changes to your control
part and data part power levels. The control part power level is adjusted by entering values in
the Pp-m field. There is no direct message part power adjustment in this mode since the
Msg Pwr field is grayed-out (inactive). However the message part power is shown in the
grayed-out field. You can also calculate your message part power by using the formulas given
in the section, “Power Control” on page 354. Figure 15-10 shows the Pp-m mode selection
along with the two fields that were mentioned earlier.
Preamble Power:
−40 dBm Pp-m: −10 dB Ctrl Beta: 15 Data Beta: 1
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