Anritsu 3GPP, Measurement Manual

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W-CDMA/HSPA+ Signal Analyzer 3-2 W-CDMA/HSPA+ Measurements
3GPP MG PN: 10580-00234 Rev. Y 3-3
Channel Power
Channel power is the total power transmitted in the 5 MHz W-CDMA channel specified.
Channel Power measures the node B/base station transmitting power across the entire
5 MHz W-CDMA (BTS) channel. Channel power is displayed in dBm and Watts.
For Over the Air (OTA) measurements, the channel power will vary as the signal path from
the node B transmitter to the instrument varies.
Scrambling Code
In the W-CDMA specification, the scrambling code can be from 0 to 511. If the scrambling
code is known, its value can be entered and the test set can decode and display the code
domain power of the signal. If the scrambling code is unknown, the instrument can be set to
auto scrambling so that the test set can lock onto the strongest code to decode and display the
code domain power of the signal.
Spreading Factor (OVSF)
According to the 3GPP standard the spreading factor can be from 4 to 512, and the
instrument can be set to a maximum spreading factor of 256 or 512.
Freq Error
Frequency error is the difference between the received center frequency and the specified
center frequency. This is tied to the external frequency reference accuracy and is typically
useful only with a good external frequency reference.
Codogram
When Codogram is selected the screen displays the changes in code power levels over time.
Noise Floor
The average power of inactive codes in the code domain, as displayed in the CDP
measurement display.
Threshold
The Active Channel Threshold Level can be set to indicate which code channels are
considered active. Any code channels exceeding this power level are considered active traffic
channels and any code channels below this power level are considered inactive (or noise). A
horizontal red line on the screen represents the threshold level. This level can be set
automatically based on the received signal, or the user can manually enter a value in the
Threshold setup menu.
Occupied Bandwidth
The measured occupied bandwidth is calculated as the bandwidth containing 99% of the total
integrated power within the transmitted spectrum around the selected center frequency.
EVM (Error Vector Magnitude)
The Error Vector Magnitude is the ratio in percent of the difference between the measured
waveform and the reference waveform. EVM metrics are used to measure the modulation
quality of a transmitter. The 3GPP standard requires that the EVM not exceed 17.5%.
EVM = (reference – measured) / reference x 100
Symbol EVM (EVM)
Symbol EVM is defined as the EVM for a single code channel.