Carrier Configuration

NI-RFmx Waveform Creator User Guide 2.4

Edition Date: November 2017

Part Number: 377063C-01

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Fig. 1-27 Carrier Configuration


This section allows you to configure the top level modulation parameters of the TDD Signal. It comprises the following controls:

Link Direction

This parameter specifies the link direction of the signal being generated.

Number of Frames

This parameter specifies the number of LTE TDD frames that will be generated. The valid range is 1 to 8. The default value is 1.

UL – DL Configuration

This parameter specifies the UL – DL Frame configuration. The valid range is 0 to 6. The default value is 0.

This controls the ratio of Uplink/Downlink subframes (Refer Table 1-3 )

Special Subframe Configuration

This parameter specifies the configuration index of special subframes generated within the LTE TDD signal. The range is 0 to 9. The default value is 0. The special subframe configuration controls the length of the DwPTS, GP, and UpPTS (Refer Table 1-4)

Channel Bandwidth

This parameter specifies the system bandwidth of the LTE signal. Valid values are 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz. The default value is 10 MHz.

The relationship of bandwidth to number of resource blocks is shown in the following table.



Table 1-13 Relationship between System Bandwidth and number of RBs


Cell ID

This parameter defines the physical layer cell identity. The range is 0 to 503. The default value is 0.

The Cell ID is automatically incremented when Downlink Test Model is configured in multiple carriers.

Oversampling Factor

This parameter defines the oversampling factor to be used in the simulation. When the Auto checkbox is selected, the oversampling rate is adjusted automatically.

CP Type

This parameter specifies the Cyclic Prefix (CP) type of the signal which is generated. Normal Cyclic Prefix and Extended Cyclic Prefix is supported.

Short Frame Generation

This parameter specifies the Short Frame Generation settings. This control enables the user to generate a limited number of contiguous slots instead of full frame.

When Short Frame is Enabled, Number of Frames is restricted to 1.

Short Frame is currently not supported for:

  • Downlink channels
  • PRACH channels

If in the Short Frame Generation settings, the Enabled checkbox is selected, it enables short frame generation, otherwise full frame is generated.

Offset (slots)

This parameter specifies the offset in slots within an LTE frame from where the waveform is generated. Valid values are 0 to 19.

Offset(slots)+Length(slots) cannot be greater than 20. Either Length(slots) or Offset(slots) is coerced to satisfy this requirement.

Length (slots)

This parameter specifies the number of slots within an LTE frame to be generated. Valid values are 1 to 20.

Offset(slots)+Length(slots) cannot be greater than 20. Either Length(slots) or Offset(slots) is coerced to satisfy this requirement.

Time Domain Windowing

Time domain windowing is not mandatory in the LTE TDD standard. The window function is employed to reduce out-of-band spectrum emissions.

State

This parameter defines whether the Time Domain Windowing function will be applied to the simulation. If this control is selected, Windowing will be employed. The default is selected (Enabled).

Duration

This is the time interval of the time domain windowing. By default, the Duration is set to 500 ns. Increasing the transition time increases the spectrum roll-off at the cost of a decreased delay spread tolerance.

Note: In order to prevent rounding/truncation of the overlap samples, it is advisable to enter values multiples of 100 ns.

The transition time range is 0 to 4600 ns.

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