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Configuring a 2x2 MIMO Test Setup

When using multiple instruments as shown in the tree view, inaccurate test data may occur if a combination of the GUI and SCPI is used to set or modify the instrument and test parameters. The software will not reflect changes made outside of the GUI even with the use of the Update from Instrument button. For all tests, use only one method to configure the settings, GUI or SCPI.

When configuring multiple instruments with SCPI instead of using the GUI, the commands must be executed for each instrument.

When using a multiple instrument configuration, the software does not use the following channels and settings.

The order of the instruments shown in the tree view follow the Closedinstrument order shown in the Hardware node window.

Where the software shows separate nodes for each instrument such as with the Instrument n and AUX Signals n nodes, the parameters apply to that target instrument. However some settings within the separate nodes are coupled so that a change to a parameter in one node changes the same parameter for the other instrument. In addition within the separate nodes, there may be some parameters that are settable for only one instrument, or set by the software for all instruments and cannot be changed. These couplings are identified in the relevant UI description topics.

For all other settings where there is only one node such as with the LTE settings and Signal IO, they apply to all instruments showing in the tree node.

  1. Setup the instruments and make the connection to eNB (BTS).

  2. Launch the software.

  3. Make the multi-instrument connection:

    1. In the Welcome screen that appears, select New hardware configuration. and then click OK.

    2. In Step 1 of System Configuration Wizard that appears next, select Closed2 Antennas.

    3. Click Next and follow the ensuing prompts.

    4. Ensure that the tree view ClosedHardware node shows multiple instruments.

      If the software is already running and there is the need to connect to multiple instruments,Run the System Configuration Wizard from the menu bar to make the change.

  4. Configure the instruments by using the Instrument n nodes.

    1. Click Instrument n in the tree view.

    2. Change instrument settings as needed.

      Ensure that within the trigger settings, the trigger delay is adjusted to provide proper instrument synchronization with eNB.

  5. Select the test:

    1. In the tree view, click LTE FDD Uplink.

    2. Click the FRC Wizard button to display the FRC Wizard dialog box with its drop-down menu choices.

    3. Click the Test Case Setup drop-down menu and select PUSCH in Multipath Fading (2 Antennas).

    4. If needed, click the FRC Selection drop-down menu to change the FRC choice.

    5. Click the Set button to complete the FRC selection process.

      This configures most of the PUSCH parameters.

  6. If there is a need, change parameters within the currently selected LTE FDD Uplink window.

  7. If the channels and Signal IO are not showing, expand the LTE FDD Uplink tree node.

  8. Configure the remaining parameters for the PUSCH:

    1. In the tree view, click PUSCH.

    2. Set the Cyclic Shift Field in Uplink-Related DCI Format setting.

    3. If needed, set the state of Activate-DMRS-with OCC to On.

  9. Configure the software to receive the eNB HARQ-ACK/NACK:

    1. In the tree view, click the UL-SCH node to display the UL-SCH setting window.

    2. Click Data Source, and use the drop-down arrow that appears to select External.

    3. If needed, use the Input Delay parameter to adjust the delay of the received ACK/NACK response.

  10. Set the marker signals and input for the eNB signal:

    1. Click Signal IO to display the Signal IO settings window.

    2. If needed, change the marker signal type (Marker 1 Signal, Marker 2 Signal, and Marker 3 Signal).

      The signal from these selections can be monitored by using the AUX Signals n nodes.

    3. Use the UL-SCH HARQ ACK/NACK Input Port parameter to select the signal generator's input AUX pin for the ACK/NACK signal from eNB.

      Ensure that the cables connected to the AUX I/O of the signal generators are wired for the AUX selection.

      For more information on AUX I/0, refer to the topic AUX I/O Connector Input Signals (MXG/EXG).

      After starting the test, if there is an issue with regards to the eNB input signal, use the AUX Signals n node to query the AUX signal and to determine the states of the AUX ports.

  11. Click the State On button to begin the test.

    Ensure that eNB is already transmitting so that the frame pulse is available to trigger the master signal generator.