FTM responder works unreliably

[Sgued]

Hello,

We are trying to work with Fine Timing measurement on the 8260 WiFi card.

Our configuration uses two 8260, one as Access Point and responder, the other as the FTM initiator. Both run Debian 10, with Linux 4.19.0-16, hostapd and the core62 release of the backport-iwlwifi driver. Similarly to this ticket, we have patched the driver to bypass the firmware flag for the FTM initiator. Using the firwmare iwlwifi-8000C-31.ucode (version 36 didn't work). We are capable of observing the FTM request packets being sent when using `iw dev wlp3s0 measurement ftm_request ftm_config_file`

We also applied the part of the patch with IWL_MVM_TOF_IS_RESPONDER.

Here are the configurations:

ftm_config_file:

<access point mac address> bw=20 cf=2412 asap

hostapd.conf:

interface=wlp3s0
ssid=ftmTest
hw_mode=b
channel=1
ftm_responder=1

 
Despite that, we are unable to make measurements. "iw" reports a "NO_RESPONSE" error, and indeed, despite being able to observe the request packets being sent using a third device in monitor mode, we can't observe any response.

However, we on very few occasions that the initiator would actually receive a response and output a measurement.

We noticed that in the driver "iwl_mvm_ftm_start_responder" was never called so we also tried patching (see attachment) mac80211 subsystem to always start the ftm responder, leading to "iwl_mvm_ftm_start_responder" being called but it didn't seem to change the behavior.

Is there anything we might have missed to enable the ftm responder?
Thanks.

[AndrewG_Intel]

Hello @Sgued

Thank you for posting on the Intel® communities.

Regarding IEEE 802.11mc - FTM protocol support, we would like to inform you that at this stage this functionality is supported by a single configuration: Intel Apollo Lake platform with Intel® Wireless AC-8260 provided under software license with out-of-the-box special Yocto image pre-installed from Original Equipment Manufacturer (OEM) partner Compulab.

For more information about the supported system configuration and setup details - please refer to the following public web page.

For more details on Compulab FTM devices supporting 802.11mc, please refer to the WiFi indoor positioning (to navigate on the website, use Fitlet2 device based on AC-8260 & Apollo Lake F3900).

No target plan for AC-8260 FTM support on Windows 10*.

However, if you are interested in this technology and would like to get FTM working for your project and allow us to check if this is supported on Linux Debian, we would like to gather more details to check this further.

We will send you an email to the email account associated with your profile in order to gather project details. Note: Please respond via private email to avoid exposing in the thread personal and/or business information.

Best regards,

Andrew G.

Intel Customer Support Technician

[Sgued]

By using the ftm-services  tool provided on the page you directed us to on the responder, we have been able to greatly improve the reliability at which we are  able to observe responses. It still varies a lot, and responses are still rare (overall 1 in 10 requests lead to a response when sending requests in a loop with iw). This is not reliable enough for us, but at least we are able to observe responses and reproduces.

We are still trying to improve the reliability and would like your help.

Thanks,
Sosthène G.

[AndrewG_Intel]

Hello Sosthène-Guédon

Thank you for your response. We are glad to know that the information provided has been helpful.

Also, we would like to confirm that we did receive your email with the information requested. We are reviewing this and we will be providing more details and/or next steps as soon as possible.

Best regards,

Andrew G.

Intel Customer Support Technician

[AndrewG_Intel]

Hello Sosthène-Guédon

We have not heard back from you after the last information we provided you through private email so we will proceed to close this thread now. If you need any other information, please submit a new question as this thread will no longer be monitored.

Best regards,

Andrew G.

Intel Customer Support Technician