Anritsu 3GPP, Measurement Manual

Page: 112 / 244

5-4 LTE Modulation Measurements LTE Signal Analyzer
5-8 PN: 10580-00234 Rev. Y 3GPP MG
5-4 LTE Modulation Measurements
The following parameters are measured in the Modulation Measurement mode.
Power vs Resource Block (RB)
This measurement displays the Power vs RB grid, an RB Color Map, the measurements table,
and measurement progress bar. See
Figure 5-6 on page 5-11 .
Two Dimensional Power vs RB Grid
Shows the PDSCH power of each RB using color. The y-axis is frequency (sub-carriers) and
the x-axis is time (sub-frame). There are ten columns for the ten sub-frames. The number of
subcarriers varies depending on the bandwidth chosen and hence the number of RBs on the
y-axis. Each cell in the grid corresponds to a particular RB in a particular sub-frame. As the
measurement progresses, each sub-frame is measured and the cells in the grid are colored
according to the PDSCH power in the RB.
Resource Block Color Map
The color mapping of the RB power level is determined by the
RB Color Map Max Value
and
RB Color Map Range
submenus. Setting these values can be done by entering them manually
or by pressing
Autoscale Color Map
.
Measurements Table
Active RBs
The number of active Resource Blocks. A RB is determined to be active if the measured
PDSCH power is above a certain threshold that indicates that the RB is being used for
carrying data.
Utilization
The percentage of RBs that carry data. It is the number of Active RBs divided by the
total number of RBs, expressed as a %.
Channel Power
Channel power is the average total power within the bandwidth and is expressed in
dBm.
OSTP
OSTP is the measurement of the OFDM symbol transmit power.
EVM
The RMS (%) of all of the error vectors between the reconstructed ideal signals and the
received signals, divided by the RMS value of the ideal signals. Individual frame
EVM(RMS) is displayed for the modulation types QPSK, 16-QAM, and 64-QAM. If the
LTE carrier uses 256-QAM modulation scheme, the corresponding EVM measurement
result is displayed, provided Option 886 is installed and activated on your instrument
(see
Figure 5-6 on page 5-11 ).
Cell ID
Cell identifying information sent by the transmitter in the sync signal.
Measurement Progress Bar
This progress bar indicates the sub-frame that is currently being measured.
Note The Power Offset is applied to the measured value before matching to a color map.