To configure downlink frame components using the MAC PDU frame setup mode:
Click Project 
in the tree view. Ensure that MAC PDU is selected in the Frame Setup Mode
in WiMAX Operation Setup table.
Click MAC-Downlink in the tree view. The MAC-Downlink Settings window displays the common downlink settings in the top half and buttons for adding bursts (maximum 16) in the bottom half.
When you use the MAC PDU mode to configure WiMAX signals, the software automatically generates the WiMAX waveform based on your configured MAC description. Click Frame in the tool bar to view a block diagram at the bottom of the window showing how the frame components fit on a time axis.
Use this cell to enter the configuration change count of the DCD. This is encoded in the DL MAP, FCH and DCD messages. Accepted values are 0 (default) to 255.
DL Channel ID
Use this cell to identify the downlink channel for transmitting the data. It is an identifier that is arbitrarily chosen by a base station in a WiMAX system. Accepted values are 0 (default) to 255.
Use this cell to select the modulation and coding rate type for the MAC PDU containing the broadcast messages.
Broadcast messages contain the DL-MAP, DCD, UL-MAP and UCD messages in the MAC PDU of the DL#1 burst preceding any regular MAC PDUs.
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According to the standard, the broadcast messages are part of the first DL burst. The Signal Studio software treats it as a separate component for clarity. For a standard-compliant WiMAX signal, this parameter should match the modulation and coding rate of the first DL burst, which should be the most robust modulation being used in the downlink. |
This cell displays the size of the TTG to be added after this burst as an integer number of samples of the sampling frequency. The maximum gap size depends on the sampling rate, oversample ratio, cyclic prefix, and frame size. Editing the Gap Interval [us] recalculates this value automatically. The minimum and default value is zero. If the frame duration is continuous, you can edit this cell.
This cell displays the size of the TTG in microseconds rounded to an integer number of samples. The maximum gap size depends on the sampling rate, oversample ratio, cyclic prefix, and frame size. Editing the Gap Interval [samples] recalculates this value automatically. The minimum and default value is zero. If the frame duration is continuous, you can edit this cell.
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adds a burst with a default MAC PDU. For each burst (maximum 16), a data grid displays some of the parameters that you can edit by clicking each cell. You can also edit a full set of parameters and add up to eight MAC PDUs per burst in the DL burst window. See Editing Tip. Editing Tip: In the MAC-Downlink Settings window, double-click the first column of the burst you wish to edit or click the burst of interest in the tree view. This displays the burst editing window. To return to the previous window, click MAC-Downlink in the tree view. For parameter definitions, see DL Burst.
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deletes a previously added burst. |
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adds a burst that has the same configuration as the currently selected burst. |
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swaps the currently selected burst with the one above it or just below it in the table for that link. |
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