Uplink (TDD) Example

This example shows how to create an uplink (TDD) waveform with one UL PUSC zone and 3 bursts using auto allocation. It assumes the you know the MAC PDUs that you want to configure, and uses auto allocation to fit those into the UL PUSC zone. You might use this configuration for some receiver test situations.

In parameter configuration windows, you can check in the upper right, and then click the desired parameter for a brief description.

  1. From the Welcome dialog, select Mx1 (Single Antenna Simulated Hardware).

  2. Click Waveform Setup in the tree view. This section contains the key system parameters. Many of the default settings are used for this exercise.

    1. Enter a name for your waveform.

    2. Built Frames: Use the default setting of 1.

    3. Output Mode: Select Uplink Only (TDD).

    4. Downlink Ratio: Use the default setting, 50.0000. This parameter determines what portion of the total frame time is available for the downlink subframe.

    5. Bandwidth: Use the default 10 MHz.

    6. Leave the default settings for the other parameters.

  3. Click Carrier 1 in tree view.

    Reference Specification: Use the default of 802.16e-2005 for this example. However, flexibility is provided to select either 802.16-2004/Cor1/D2 or 802.16-2004/Cor1/D3 depending on which standard specifications you want to use for subchannel randomization and subcarrier allocation.

    Hint: Click the frame tab in the lower portion of the window to display the frame plot view. A small yellow triangle at the bottom of the graph indicates the division between the downlink and uplink. The available subframe time determines how many symbols can be put into the subframe (see Closedexample.) Note that the RF burst off time will include any unused frame time, shown as gap (TTG), plus the downlink portion (grayed out) of the TDD frame when the Output Mode is Uplink Only (TDD).

    Refer to section 8.4.2.3 of the 802.16-2004 standard for parameter definitions.

    For a 10 MHz BW:

    • Sampling frequency: Fs = 11.424 MHz

    • Subcarrier spacing: 11.15625 kHz

    • Useful symbol time: 0.0896 ms

    • For G=1/8, CP time: 0.0112 ms

    • OFDMA symbol time: 0.1008 ms

    With a frame length of 5 ms and a 50% downlink ratio selected, there is 2.5 ms available or 24 symbols maximum.

  4. Click Uplink in tree view. The top half shows various uplink parameters that are automatically calculated by the software. These cannot be modified. The bottom portion of the screen allows you to add PUSC, OPUSC, AMC or Sounding zones (maximum 3) to the uplink. The software already has a PUSC zone by default. Use this zone with a default burst and MAC PDU.

  5. Click Zone#1, PUSC under Uplink in the tree view. Set the following parameters:

    1. Auto Allocation: Use the default (On).

    2. Number of Symbols: This parameter starts at 3 and will be incremented by the software as more MAC PDUs are added. Note that this must be a multiple of 3 because the UL PUSC zone is divided into slots which are 1 subchannel x 3 symbols (section 8.4.3.1).

    3. Note that the Max Number of Subchannels available is 35.  

    4. The lower half of the screen allows you to add regular bursts, HARQ bursts or collaborative bursts. click and select regular burst to add two regular bursts. Fields that are white in the table may be edited either here or from the burst editing window.

  6. Click Burst#1 under Zone#1 in the tree view to display the burst editing window. (You can also double-click in first column for Burst#1 in the table.) Leave all default values. Note that a power offset can be added to the burst. In the lower portion, one MAC PDU has been added by default.  

    1. Enter a number for the CID (Connection Identifier) from 0 to 65535. This identifies a connection between the base station and a specific subscriber station.

    2. Change Data Length to 500 bytes and note the increased size of the zone in the frame view and the burst allocation in the zone plot in the lower right. The zone is now extended from symbol 0 to symbol 8.

  7. Click Burst#2 in the tree view to configure the next burst.

    1. Choose Modulation and Coding to be 16QAM 1/2. Note that a MAC PDU was automatically added in the lower half.

    2. Enter a value for CID different from the one you previously used to indicate this MAC PDU is for a different subscriber station.   

    3. Click Data Type and select PN9.

    4. Change Data Length to 600 bytes. Note in the zone plot in the lower right that the zone now extends out to symbol 14. Also note Burst#2 is smaller than Burst#1 (even though there are more data bytes) due to the higher order modulation. 

  8. Click Burst #3 in the tree view.

    1. Choose Modulation and Coding to be 64QAM 2/3.

    2. Set Power Offset to 2 dB. 

    3. Set the CID to any valid value.  

    4. Set Data Length to 1000. Note the zone now extends to symbol 17, but it is not full.

  9. Click Check Parameters to verify all parameters are okay. View the result in the Status window at the bottom of the main window.

  10. Click on Waveform Setup in the tree view to view the CCDF, Waveform, or Power Envelope graphs at the bottom of the page if desired.

  11. Click Generate to generate waveform.

  12. Click Download to download waveform to the instrument if you have configured the instrument connection.