3GPP Signal Analyzer Measurement Guide for Anritsu RF and Microwave Handheld Instruments : WCDMA/HSDPA Signal Analyzer : WCDMA/HSDPA Measurements

WCDMA/HSDPA Measurements
Carrier Frequency
Carrier Frequency is the selected transmitter operating center frequency entered by the user or calculated from the signal standard and channel number entered by the user.
Carrier Feedthrough
Carrier Feedthrough measures the amount of unmodulated signal that is leaking through the transmitter and is displayed in the Code Domain Power display. The WCDMA 3GPP specification does not specify carrier feedthrough measurement.
Code Domain Power displays how much of the channel power is in each Orthogonal Variable Spreading Factor (OVSF code). Power is normalized to the channel power, so if a code reads – 10 dB, it means that the code is 1/10th of the channel power. Colors are applied according to Table: Channel Power Colors.
Primary Common Control Physical Channel
Secondary Common Control Physical Channel
High Speed Physical Downlink Shared Channel
HSDPA Screen and CDP Screen when the WCDMA/HSDPA option is installed
In WCDMA specification the P‑SCH and S‑SCH are not assigned spreading codes and therefore do not appear in the code domain power display. They have special non‑orthogonal scrambling codes and are on 10% of the time.
Channel Power
Channel power is the total power transmitted in the 5 MHz WCDMA channel specified. Channel Power measures the node B/base station transmitting power across the entire 5 MHz WCDMA (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 WCDMA 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.
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.
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.
Peak to Average Power
Peak to Average power is the ratio of the peak power and the RMS power of the signal calculated over one frame interval and is displayed in dB.
Peak CD Error (Peak Code Domain Error)
PCDE takes the noise and projects the maximum impact it will have on all OVSF codes. PCDE is the maximum value for the code domain error for all codes (both active and inactive).
In the 3GPP standard, in order to address the possibility of uneven error power distribution in WCDMA, the EVM measurement has been supplemented with PCDE. The 3GPP standard requires that the PCDE not exceed – 33 dB at a spreading factor of 256.
Ec is a measurement of energy. Ec is determined by multiplying CPICH by the chip time.
The pilot power compared to the total channel power. Ec/Io is displayed in text‑only displays and in OTA measurement displays.
Pilot Dominance
The strength of the strongest pilot compared to the next strongest pilot in the same channel. This should be >10 dB in order to make good measurements.
OTA Total Power
The total channel power is also called (Io) and displayed in dBm.
CPICH power is the power of the Common Pilot Channel power displayed in dBm.
P‑CCPCH power is the Primary Common Control Physical Channel power displayed in dBm.
S‑CCPCH power is the Secondary Common Control Physical Channel power displayed in dBm.
PSCH Power
P‑SCH power is the Primary Sync Channel power displayed in dBm.
SSCH Power
S‑SCH power is the Secondary Sync Channel Power displayed in dBm.
PICH is the Paging Indicator Channel Power.
HSDPA Power versus Time Display
Select the code and set the time to display how the code is varying over time. In CDP view, HSDPA signals are displayed in orange.
In the HSDPA view, the symbol constellation for the selected code is displayed (16QAM or QPSK).

Copyright 2012 Anritsu Company
Anritsu Company
10450-00022, Rev. D