WLAN Packet Error Rate Test in LabVIEW

This example program uses the WLAN toolkit for LabVIEW to generate WLAN packets and determine the percentage that are received correctly. The example was developed to test antennas that were intended to be used for transmitting WLAN data.

Introduction

This example program uses the WLAN toolkit for LabVIEW to generate WLAN packets and determine the percentage that are received correctly. The example was developed to test antennas that were intended to be used for transmitting WLAN data.

To do this, we generate a WLAN signal on an RF Signal Generator and acquire the data on an RF Signal Analyzer.  We don't actually compare the individual bits that are transmitted, but instead we check to make sure the header information was correct and make sure there were not triggering errors or missed packets.  

The program gradually decreases the power by the amount specified and generates a specific number of packets at each power.  In the end, you are given a chart that displays packet error rate against generation power.  

Requirements

This example program needs several things to work.  First, you need LabVIEW, the WLAN toolkit, and drivers for all the required hardware installed on a computer.   As far as hardware goes, the example program requires an RF Signal Generator, an RF Signal Analyzer, a preamplifer (NI-5690), and antennas to test.

Using the Example Program

Because you will be transmitting data using antennas, we need to characterize the expected path loss and determine the amount of gain to apply using the preamplifier.  To do this, first run the VI called Get Signal Characteristics.vi.  Specify the correct resources and leave the preamplifier gain at 0.  After running the VI, you should get an attenuation value, which will be your path loss.  Now that you know your path loss, you can set a gain that is appropriate.  Run the VI again and obtain a path loss value with the gain applied.  Record the gain value that you used and the new attenuation/path loss values.  

Now open the WLAN Packet Error Rate VI. Specify the correct hardware resources, WLAN standard to use, and power levels to test.  Also enter the Gain and path loss from your previous test.  When choosing your packets per step and the amount of power levels to test, keep in mind that the test could take a long time if too many steps or packets per step are specified.  Now run the VI.  If your starting power is great enough, you should receive 100% of the packets at first.  As the generated power decreases, the amount of packets received will decrease rapidly and eventually go to 0.  

Requirements

Filename: wlanper.zip

Software Requirements

Application Software: LabVIEW Base Development System 2009
Language(s): LabVIEW

Hardware Requirements

Hardware Group: RF

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