WL18xx RX Testing

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Introduction

This section will review how to use the RX statistics command for receiving (RX) testing on the WL18xx.

RX Statistics Commands

The WL18xx firmware is able to capture packets from the air and report RF statistics. This functionality can be used to make sure the calibration, antennas, and radio on the device are working properly.

To begin, use the power_mode command to reset the system to PLT mode.

 calibrator wlan0 plt power_mode on

To start calculations of RX statistics, use the start_rx command:

calibrator wlan0 wl18xx_plt start_rx <source address> <destination address>

NoteNote: : Using broadcast MAC (FF:FF:FF:FF:FF:FF) instead of source and/or destination addresses causes it to be ignored.

To receive RX statistics, use the get_rx_stats command:

calibrator wlan0 wl18xx_plt get_rx_stats

It is important to finish with the stop_rx command:

 calibrator wlan0 wl18xx_plt stop_rx

Examples

root@am335x-evm:~# calibrator wlan0 plt power_mode on
root@am335x-evm:~# calibrator wlan0 wl18xx_plt tune_channel 6 0 0
root@am335x-evm:~# calibrator wlan0 wl18xx_plt start_rx 00:00:00:00:00:01 00:00:00:00:00:02
root@am335x-evm:~# calibrator wlan0 wl18xx_plt get_rx_stats

// No incoming. Verify no noise, zero packets received
RX statistics (status 0)
Total packets:          0
FCS errors:             0
MAC mismatch:           0
Good packets:           0
Average RSSI (SOC):     0
Average RSSI (ANT):     0
PER:                    N/A     # PER = Total Bad / Total Received

// First run 1000 packets burst signal level -75dBm (~98% reception)
RX statistics (status 0)
Total packets:          1000
FCS errors:             15
MAC mismatch:           0
Good packets:           985
Average RSSI (SOC):     -75
Average RSSI (ANT):     -72
PER:                    0.015     # PER = Total Bad / Total Received

// Second run (+1000) signal level -76.5dBm (~90% reception) - sensitivity point
RX statistics (status 0)
Total packets:          2000
FCS errors:             169
MAC mismatch:           0
Good packets:           1831
Average RSSI (SOC):     -77
Average RSSI (ANT):     -74
PER:                    0.0845    # PER = Total Bad / Total Received

calibrator wlan0 wl18xx_plt stop_rx

NoteNote: :

  • FCS error is frame corrupted in PHY level.
  • MAC Mismatch is good WiFi frame not addressed to device
  • PER = Total Bad / Total Received

RX Statistics Use Case

The use-case below uses calibrator commands to have Rx Statistics on specific channel.

To begin, use the power_mode command to reset the system to PLT mode.

 calibrator wlan0 plt power_mode on

Then we can set-up to use the get_rx_stats command:

calibrator wlan0 wl18xx_plt tune_channel <channel> <band> <bandwidth>
calibrator wlan0 wl18xx_plt start_rx
calibrator wlan0 wl18xx_plt get_rx_stats
calibrator wlan0 wl18xx_plt stop_rx
calibrator wlan0 plt power_mode off

NoteNote: Supported channels

Channel Band
1-14 0 - 2.4GHz
8(J8), 12(J12),16(J16), 36, 40, 44,48, 34(J34), 38(J38),42(J42), 46(J46),52,
56, 60, 64, 100,104,108, 112, 116, 120,124, 128, 132,136,140,149,153, 157,161, 165
1 - 5GHz
16(J1), 12(J2), 8(J3),
4(J4)
2 - 4.9GHz

NoteNote: Supported Bandwidths

0 - No HT
1 - HT 20MHz
2 - HT 40MHz lower
3 - HT 40MHz upper

For more information on some of the other commands used in this use-case, please see the WL18xx TX Testing page.