Physical Mode: Basic Uplink Setup

This example shows how to configure and download a basic uplink waveform to the signal generator using the Physical as the frame setup mode.

Step 1: Select a Quick Setup

Step 2: Configure the Project Property Parameters

Step 3: Configure the Signal Generator Settings

Step 4: Configure the Uplink Frame Structure

Step 5: Generate and Download the Waveform

Step 1: Select a Quick Setup

  1. Click Quick Setup in the tree view and then click the 802.16-2004 WiMAX button in the right pane to access the main window.

  2. Notice that Project is highlighted and the parameter view displays three panes: Project Property, Projected Waveform, and Signal Generator Settings.

Step 2: Configure the Project Property Parameters

  1. In the Project Setup table:

  2. Change the default Project Name (Untitled) to a unique name of eight characters or less. You may also enter a Project Comment to describe the waveform.

  1. Use the WiMAX Basic Parameters table to edit waveform generation parameters. Set up a waveform with the following characteristics:

  1. Select Physical for the frame setup mode in the WiMAX Operation Set Up pane under Project Property.

  2. In the WiMAX Signal Configuration table:

These markers are linked to the marker settings in the Basic Arb section of Signal Generator Settings. Markers3-4 are used by the software to control the RF blanking and ALC settings for waveform playback, so they should not be modified.

 

  1. Observe the waveform's length characteristics in the Projected Waveform pane. The Data Points cell is calculated as follows: [Data Points] = [Sampling Clock] * [Frame Duration] * [Built Frames].

Step 3: Configure the Signal Generator Settings

  1. Configure the signal generator's frequency, amplitude, and arbitrary waveform playback parameters in the Signal Generator Settings pane. Set Frequency to 3.5 GHz and Amplitude to –10 dBm.

The signal generator amplitude setting refers to the average power level of the FCH/Bursts, as indicated by Amplitude Reference. The preamble power level is defined in the standard to be 3 dB higher than the level of the rest of the burst, so it will always be 3 dB higher than the amplitude setting of the signal generator. If you create a waveform that only has a preamble, select Preamble as the Amplitude Reference.

The Amplitude Reference also determines the portion of the waveform that is used by the signal generator for ALC leveling. In some cases, choosing the Amplitude Reference to be the preamble instead of FCH/Burst may result in better RCE (EVM) since, in some cases, the RCE (EVM) of the signal can vary based on the data in the waveform.

 

  1. The sampling clock frequency for the signal generator is automatically calculated as [Sampling Clock] = floor(n * Bandwidth / 8000) * 8000* OSR. This is the same as the “sampling frequency” defined in the IEEE 802.16-2004 standard.

Step 4: Configure the Uplink Frame Structure

  1. Click Physical in the tree view. The frame view displays the frame structure in the right pane, with the downlink subframe on the top half and the uplink subframe on the bottom half.

  2. In the uplink subframe, click Add Preamble followed by Add Burst three times to add three uplink bursts from three different subscribers, each preceded by a preamble. Click Add Gap to end the subframe with a gap. The new frame components are added to the table and the tree view. The gap (also referred to as the receive/transmit transition gap or RTG) allows the base station time to change from receive to transmit mode.

  3. Click Frame in the tool bar to display a plot of the frame layout with the new preambles and bursts. Clicking Frame again will hide the plot.

  4. Edit the burst parameters. Double-click in the first column in the table for the item, or click on the item in the tree view on the left. A window appears that shows parameters specific to the selected burst type. Change the parameters as follows:

    Deleting and Moving Components

    To delete a particular frame component, click anywhere in the row of that item and then click Delete.

    To change the order of the frame components, click anywhere in the row of that item and use the up or down arrow to move it higher or lower in the table.

  1. Click Physical in the tree view to go back to a view of the overall frame.

  2. Click the Check Parameters button in the tool bar to verify that the configured bursts do not exceed the length of the defined frame. If the configuration is valid, a result message "Parameters are fine" will be shown in the status bar at the bottom of the window. If not, a message "Defined frame exceeds the maximum frame length" appears.

Step 5: Generate and Download the Waveform

  1. From the tool bar, click Generate. The software generates an I/Q waveform file in accordance with the current physical channel configuration and waveform generation setup. Waveform generation time varies proportionally with the complexity and length of the waveform. Messages showing the waveform generation progress and status are displayed in the status bar.

  2. From the tool bar, click CCDFs to toggle the graph view on and off. The graph view enables you to examine waveform characteristics, such as baseband spectrum, I and Q signals, and CCDF curves, prior to downloading the file to the signal generator.

  3. From the tool bar, click Download to generate and download the waveform to the signal generator. The waveform file automatically begins to play. You can re-enable local control of the signal generator by pressing the Local hardkey, enabling you to modify signal generator settings from the front panel. The waveform file cannot be modified after downloading it to the signal generator. However, the carrier frequency and amplitude can be changed.

You can use the 89601A software (version 5.3) with Option B7S (802.16 Modulation Analysis) to view the waveform on a signal analyzer such as the E4406A (VSA) or others in the PSA family.

Related Topics

User Interface Basics

Using the MAC Editor

Frame Plot View

Graph View

Understanding CCDF Curves

 

Related Websites

IEEE 802-16-2004 standard
ESG product information
PSG product information
MXG product information
Agilent Signal Studio software