Carriers (5G NR)

The Carriers panel contains carrier aggregation parameters for the 5G NR signal.

Aggregation combines up to 16 component carriers into a single signal. The Aggregation feature provides the ability to customize component carriers using a single signal definition, or mix and match component carriers with multiple carrier definitions.

Link Direction - Sets the link direction for the carriers in the Aggregation Table.

Downlink- When selected, all carriers in the Aggregation Table are set to Downlink.

Uplink- When selected, all carriers in the Aggregation Table are set to Uplink.

Mixed- When selected, a new Link column is displayed in the Aggregation Table to individually set the link direction for each carrier. The Mixed choice becomes available when Allow Multiple Carrier Definitions is enabled.

Default: Downlink

Choices: Downlink, Uplink, Mixed

Configure... - Selects a predefined carrier aggregation configuration as a starting point for your scenario.

Single Carrier - Configures a single component carrier.

nCC, Contiguous - Configures n component carriers. When Allow Multiple Carrier Definitions is enabled, a separate carrier definition is created for each component carrier.

Carrier per-input channel - Configures a component carrier for each input channel configured in Input > Channels. The Carrier per-input channel selection allows you to map input channels into component carriers to support non-contiguous carrier aggregation measurements with multi-channel hardware. Each input channel may have a different measurement channel center frequency, as configured in the Channel Centers... dialog (or by using MeasSetup > Frequency > Center). The component carrier's center frequency is shown in the Aggregation Table's Tx DC Freq. column. See Sequential Input Channel Acquisition Overview for more information and an example.

Default: Single Carrier

Choices: Single Carrier; 2CC, Contiguous; 3CC, Contiguous; 4CC, Contiguous; 5CC, Contiguous; 6CC, Contiguous; 7CC, Contiguous; 8CC, Contiguous; Carrier per-input channel

+ Add Carrier - Adds a new carrier mapping with a 0 Hz frequency offset to the bottom of the Aggregation Table using parameter values matching the current reference carrier. Click a newly added carrier's Enabled checkbox to include it in the aggregate signal.

Allow Multiple Carrier Definitions - When enabled, each newly added component carrier will have its own, separate, incrementally numbered carrier definition and the Link Direction setting's Mixed choice becomes active. You can change Component Carrier n : Carrier Definition n (CCn : CDn) mappings after adding component carriers by changing the Carrier Definition assignments in the Aggregation Table's Carrier Def column.

When disabled, the Carrier Def column disappears and all component carriers in the Aggregation Table use a single signal definition.

Reference - Sets the carrier to be used as the reference carrier. The reference carrier is the reference point for cross-carrier measurement results like TAE.

Default: CC0

Choices: All enabled carriers in the carrier aggregation table.

Display - Sets the component carrier to be used for calculating carrier-specific trace data. This parameter affects the traces that are selected in Trace > Data > Demod > Selected Display CC and Trace > Data > MIMO > Selected Display CC. The selected component carrier will appear as "(CCn)" in the title of all affected traces. See About Per-Carrier Trace Types for more information.

Default: CC0

Choices: All enabled carriers in the carrier aggregation table.

Aggregation Table Parameters

CCn - The checkbox next to each component carrier in the Aggregation Table includes or excludes the carrier in the aggregate signal. For predefined configurations (see Configure...), component carriers are enabled and included in the aggregation. For newly added carriers (see Add Carrier), carriers are disabled and excluded by default.

Link - Assign link direction to the selected carrier. This column appears when Allow Multiple Carrier Definitions is enabled and Link Direction is set to Mixed. Since this parameter changes the carrier definition, the link direction of other component carriers that are mapped to the same carrier definition will also change.

Cell ID - Sets the Cell ID for the selected carrier. When the checkbox is selected, Cell ID autodetection is enabled for the carrier. Automatic Cell ID numbering begins from 1, based on version 15.5.0 of 38.211 (2019-03).

Bandwidth - Sets the bandwidth for the component carrier's carrier definition. Since this parameter changes the carrier definition, the bandwidth of other component carriers that are mapped to the same carrier definition will also change. This setting performs the same functionality as the Bandwidth panel's Bandwidth setting, but it may be more convenient to use this setting when configuring carrier aggregation.

Carrier Center – Sets the carrier center frequency. Carrier Center is calculated as the sum of the mapped measurement channel’s center frequency and the carrier’s Freq. Offset value. Since Carrier Center is coupled with Freq. Offset, changing one setting will change the other setting accordingly.

Frequency for Phase Compensation selects the component carrier's symbol phase compensation method and transmitter radio frequency. Symbol Phase Compensation is used to compensate for phase differences between symbols caused by upconversion or downconversion. Double click, click the drop-down arrow or start typing in the text box to open the dialog. For more information on 5G NR modulation and upconversion, see TS38.211 Section 5.4.

From Carrier Center - The carrier center frequency is used as the transmitter radio frequency for purposes of symbol phase compensation.

From Manual Entry - The "Radio Frequency" edit box becomes available, and the value entered is used as the transmitter radio frequency (for purposes of symbol phase compensation). This entry is also used in the Ref. Pt. A read-only feedback label.

Disabled - No symbol phase compensation is applied, the measurement center frequency is used in the Ref. Pt. A read-only feedback label.

Radio Frequency - When From Manual Entry is selected, the value entered in the Radio Frequency field will be used as the transmitter radio frequency for purposes of symbol phase compensation.

Default: From Carrier Center

Choices: From Carrier Center, From Manual Entry, Disabled

NR Band - In order to measure Uplink Spectrum Flatness, F_UL_Low and F_UL_High are needed as specified in the 5G NR standard. There are three ways to enter these values:

Auto - When selected, F_UL_Low and F_UL_High are decided by the carrier center frequency and carrier bandwidth.

Band Index - When selected, set the band index in the field next to the NR Band drop-down to decide F_UL_Low and F_UL_High based on the tables in section 5.2 of TSTechnical Specification 38.101 and TS 38.521 of the 5G NR standard.

Band Frequency - When selected, set F_UL_Low and F_UL_High manually.

Default: Auto

Choices: Auto, Band Index, Band Frequency

F_UL_Low - Specifies the low-end frequency of the UL operating band for use in UL Spectrum Flatness measurements. This field becomes editable when NR Band is set to Band frequency.

F_UL_High - Specifies the high-end frequency of the UL operating band for use in UL Spectrum Flatness measurements. This field becomes editable when NR Band is set to Band frequency.

Tx DC Freq. - Specifies the transmitter DC frequency for the selected carrier. IQ Offset and IQ Imbalance Estimation/Compensation for each carrier can only be calculated when DC frequency falls within the analysis bandwidth of that carrier.

Carrier Def - Assigns a carrier definition to the component carrier. This column appears when Allow Multiple Carrier Definitions is enabled. It is possible to map multiple component carriers to the same carrier definition, or you can map each carrier to its own carrier definition (default).

When a component carrier is added to the table, a new, incrementally numbered carrier definition (starting with CD0) is added with the new carrier. You can change Component Carrier : Carrier Definition mappings after adding component carriers by changing the carrier definition assignments. See CCN : CDN for more information.

Remove Carrier - Removes the selected row from the carrier aggregation table.

If the carrier assigned as the Reference Carrier is removed, the first row with an enabled carrier becomes the reference carrier, or if no remaining carriers are enabled, the first row becomes enabled and becomes the reference carrier.

Open Test Model... - Opens the Test Model dialog for configuring a standard-based test model. Test Models are only available for downlink signals.

Cross-Correlated EVM -

Cross-Correlated EVM (ccEVM) computes EVM by combining the results of two different measurements of the same signal so as to reduce the noise contributed by the acquisition hardware. This procedure causes the ccEVM value to primarily contain the noise coming from the DUT (or source and DUT, in the case of an amplifier).

Each resource element (subcarrier x symbol) is weighted equally when computing the ccEVM average.

If the channels are not completely independent (e.g. shared LO), this technique will not be able to remove the common noise between channels.

All channels must make a measurement at the same point in time. The signals don't need to be phase-aligned, but both 5G NR measurements must demodulate the same frame. If there is a difference between the frames, the Cross-Correlated EVM Summary trace will show a DATA? trace LED. This won't necessarily catch the case where two different frames in time are analyzed by each measurement. To avoid this case, make sure that no more than one frame is captured (adjust the parameters on the Time tab and verify with the Search Time trace).

Refer to the appropriate hardware topic to configure your hardware for a multichannel acquisition.

Cross-Correlated EVM is only available when the number of input channels is greater than one, and even (2, 4, 6, etc.). Two measurements will be performed on half of the measurement channels. Each measurement will be assigned a contiguous block of channels (channels 1 to N/2 assigned to Meas1, channels N/2+1 to N assigned to Meas2).

To perform a successful measurement, make sure the following are true:

Each DUT channel (call it channel k) is connected to appropriate hardware channels through a splitter (hardware channels k and k+N/2). See Making Cross-Correlated EVM Measurements for MIMO CcEVM configuration examples.

Input > Channel configuration is set to an even number of channels.

CC0 and CC1 share the same component carrier definition.

In the Input & Antenna tab, map half of the channels (1:N/2) to CC0 and the other half of the channels (N/2+1:N) to CC1.

The same frame is being analyzed by both CC0 and CC1 (to ensure, use frame trigger and set Acquisition Mode to Frame Trigger is Present)

Sequential acquisition is not in use.

Analysis Start Boundary should be set to Frame to make sure that the same data is being analyzed by both component carriers in the ccEVM measurement.

Enabled - Turns on Cross-Correlated EVM and enables the Cross-Correlated EVM Summary trace for viewing results.

Configure - Opens a dialog to select the CC to be duplicated to CC0 and CC1, and sets the input channels appropriately.