Ch Frequency Response (5G NR/5G-Advanced)

There are two types of traces in the Trace > Data > Demod and MIMO Multiple Input, Multiple Output: A physical layer (PHY) configuration in which both transmitter and receiver use multiple antennas. menus that display component carrier data: CCn (component carrier is fixed), and Selected Display CC (component carrier is dynamically selected using the Display parameter). See About Per-Carrier Trace Types for more information.

The Ch Frequency Response trace displays the channel frequency response on the reference path (decided by reference input channel and reference DMRS port). If the reference DMRS port is not active on the reference input channel, the reference path is inactive, and the VSA software will use the path whose power is maximum as the reference path. Channel Frequency Response is optimized using the Equalizer Training settings. See the MIMO Eq Ch Freq Resp trace topic for individual user/path channel frequency response.

When Per Slot Channel Frequency Response is selected, the results are presented as per-slot overlaid results. Markers can be used to associate a particular point on the trace with a specific slot and subcarrier. When Per Slot Channel Frequency Response is cleared, all slots are combined in a single channel frequency response calculation.

When more than one carrier is defined in the Aggregation Table, "(CCn)" will appear in the title of this trace, where "n" is the number of the component carrier whose data is displayed in the trace. Select the desired component carrier number using the Configuration > Carriers > Display parameter.

The set of physical channels contributing to the Channel Frequency Response depends on the measurement configuration:

If ULBWP is enabled, all enabled physical channels associated with the ULBWP (PUSCH, PUCCH, etc.).
Else if DLBWP is enabled, all enabled physical channels associated with the DLBWP (PDSCH Physical Downlink Shared Channel, PDCCH, etc.).
Else if SSBlock is enabled, all enabled physical channels associated with the SSBlock (SSS, PSS, PBCH, etc.).

The time region described by Subframe Offset/Symbol Offset/Subframe Interval/SymbolInterval is included in channel frequency response results (including partially occupied slots).

If SSBlock and DLBWP are both enabled, DLBWP must be disabled to show channel frequency response results from SSBlock channels.

The first measurement input channel is used to compute the channel frequency response results.

The resource grid definition will determine the minimum and maximum subcarriers provided in the Channel Frequency Response trace. If a slot does not contain active subcarriers within the set of physical channels (described above), placeholder results will be provided with 0 dB and 0 degree value.

Result normalization is performed slot-by-slot. Varying allocation patterns across slots will therefore likely contain magnitude and phase offsets across slots.