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142 Chapter 5
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CDMA Measurements - Screens and Control Fields
CDMA Measurements
Figure 5-8 Code Domain Timing and Phase
Screens on which this measurement is displayed
• CODE DOM (Code Domain Analyzer, IS-95 only)
Code Domain Measurements – IS-2000
If you have selected IS-2000 in the INSTRUMENT CONFIGURE
screen, the Code Domain screen will appear as described in this section,
with a default Walsh Code ordering following the Bit Reverse paradigm,
with 128 channels.
If you wish to make use of the traditional Walsh ordering - Hadamard -
as described by the IS-95 standard, see “Meas Order” on page 163.
Bit Reverse, or Walsh index ordering display mode for Code Domain
Power is a newly defined order for code domain measurements
supporting IS-2000 CDMA. This coding sequence differs from IS-95’s, or
Hadamard ordering as shown in Figure 5-10.
Advantages of Using IS-2000
The CDMA standard, IS-2000, offers a number of enhancements to the
IS-95 standard including the following:
• Reverse Link Pilot for Each Mobile – Allows base stations to perform
synchronous detection during demodulation, resulting in a
performance gain.
• True QSPK Modulation – Yields 2 bits per symbol, allowing twice the
processing gain to be applied to both I and Q data. This, more
efficient modulation also allows for stronger convolutional encoding.
• Continuous Reverse Link Waveform – Continuous (no pulse) reverse
link provides less biomedical interference and better transmit power
averaging.
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Time
Phase
Walsh Code
Walsh Code