Viavi CellAdvisor 5G, Руководство пользователя

Страница: 299 / 359

CellAdvisor 5G User's Guide
287
OTA multipath profile
The Multipath Profile enables you to determine RF environmental conditions of testing area. It indicates the amount of power of the
dominant pilot signal that is dispersed outside the main correlation peak due to multipath echoes that are expressed in dB. This
value should be very small ideally.
The multipath profile is the result of portions of the original broadcast signal arriving at the receiving antenna out of phase. This can
be caused by the signal being reflected off objects such as buildings or being refracted through the atmosphere differently from the
main signal.
Setting measure setup
After configuring spectrum measurement in " Configuring Spectrum Measurements ", you can set the measure setup to continue your
measurement. The measurement settings can be saved and recalled as a file by selecting File Type as Setup and load the file onto
the instrument using the
Save/Load icons on the side bar.
1 Tap the Setup ( )icon on the side bar.
2 Tap to switch Carrier Auto Search to Start to start searching the SSB frequency and apply it or to Stop to stop searching.
NOTE
If searching is unavailable, the instrument displays a pop-up message saying that it fails to detect NR (SSB)
frequency.
3 Tap to switch Radio Config and set Duplex Type (FDD/TDD), DSS Type (Co-channel/ Adjacent channel ), and Technology
(LTE/NR) and other related parameters as below:
You can select Co-channel to find NR frequency based on the LTE operating frequency in co-channel and select Adjacent
channel to search both LTE and NR frequency. Note that Adjacent channel will be available in the next release.
When LTE is selected as Technology , do the following steps:
a Select Bandwidth (MHz) from the following choices: 20 , 15 , 10 , or 5 .
b Select MIMO between 2x2 and 4x4 to set the number of antenna ports.
If the MIMO is set to 2x2, the antenna ports 2 and 3 are disabled.
c Select Cyclic Prefix between Normal and Extended .
Cyclic prefix works as a buffer region or guard interval to protect the OFDM signals from inter symbol interference.
▪
Normal : Intended to be sufficient for the majority of scenarios
▪
Extended : Intended for scenarios with particularly high delay spread.
d Select PHICH Ng between Normal and Extended and then to set the number of PHICH groups (Ng) : 1/6 , 1/2 , 1 , or 2 .
The PHICH group value/Ng is decided based on the number of PHICH groups per subframe. PHICH duration is a higher
layer parameter configured either as Normal or Extended
that says the demodulator how many symbols per
subframe are used by PHICH
.
▪
Normal : There are 8 PHICH sequences in one PHICH group (4 symbols).
▪
Extended : There are 4 PHICH sequences in one PHICH group (2 symbols).
When NR is selected as Technology , do the following steps:
a Select Sub-Carrier Spacing as 15 kHz (Case A) .
The standard for NR SCS is 15 kHz and CellAdvisor 5G supports 15 kHz of sub-carrier spacing.
4 Tap Antenna Port to assign an antenna port number automatically or manually, and select from Auto , Antenna 0 , or Antenna
1 .
If the MIMO is set to 2x2, the antenna ports 2 and 3 are disabled.
5 Tap to switch CFI to Manual or Auto .
▪
Auto lets the instrument set the number of OFDM symbols used for transmitting PDCCHs in a subframe.
▪
Manual sets the number of OFDM symbols manually. The set of OFDM symbols that can be used for PDCCH in a
subframe is given by 0, 2, 3 or 4 in 1.4 MHz bandwidth and 1, 2 or 3 in other bandwidths.