nRF7002 STA+AP with Different Channels

RE: nRF7002 STA+AP with Different Channels

Hanan619 — Wed, 12 Feb 2025 11:53:48 GMT

Hi esmart-engineering

I am trying to create virtual interfaces to run both sta and softap at the same time on zephyr.

I am using nrf7002dk.

Can you please share how you have setup virtual interfaces so that to achieve this?

RE: nRF7002 STA+AP with Different Channels

Simonr — Wed, 25 Sep 2024 13:24:01 GMT

A statement from one of our devs:

Since the nRF70 series devices have a single radio, multi-channel operation is not possible, so the behavior you describe is expected.

Best regards,

Simon

RE: nRF7002 STA+AP with Different Channels

esmart-engineering — Fri, 20 Sep 2024 03:34:28 GMT

To be clear, this is the current state of our usage for nrf7002:

We are creating a Linux driver, which does not use zephyr at all. The majority of the documentation online is centered around zephyr which has very little use to us.
We do use a slightly outdated version of nrfxlib at the moment, specifically commit 2fe3e82 made on march 14 2024, with modifications to make it work on our version of linux and our use case
Your above quote states that an interface (singular) cannot operate as both an AP and STA, but we are using multiple virtual interfaces on a single nrf7002. The chip and firmware supports this, and if configured correctly does work. We've been able to route traffic from the AP to the STA interface and have tested with video and calling.

Currently our issues with this setup is as follows:

Configuring STA to connect to a wifi network, and configuring the AP to start on the same channel works. As long as both are using the same channel we haven't seen any issues.
If STA is configured to connect to a wifi network on channel 1, and AP is configured on channel 6, or channel 36 (for 5GHz), then starting the AP returns a -16 status, and the AP does not start at all.

My specific question is: Is it at all possible to get both STA and AP running on two different channels?

There is no concrete documentation on whether it is possible or not, and if it is feasible I need to know how. I've combed pretty much all the available documentation for the chip and haven't found anything that can answer my question. I'm looking for any technical advice or documentation to answer this.

RE: nRF7002 STA+AP with Different Channels

Simonr — Thu, 19 Sep 2024 10:43:51 GMT

There's a lot of theory behind this question, and after discussing this with a colleague here in tech support it seems like we need to involve the development team to get a concrete reply here.

From what we're able to glean, a network interface can't operate as both SAP and STA, and thus this would be a no altogether, based on the following line:

A network interface can operate in either SAP mode or Station mode, but not in both modes simultaneously.

Please explain how you mean you're able to use it both as an access point and station on your end exactly so that I can go to the experts with a more direct question. EIther way, the channel switching you request is not supported in the Zephyr SDK and I don't see how it would be possible either.

Best regards,

Simon

RE: nRF7002 STA+AP with Different Channels

esmart-engineering — Thu, 19 Sep 2024 02:13:23 GMT

I've tried using both a combination of 2.4 and 5 GHz channels, and channels in the same band (channel 1 and 6 is my common goto). I've looked into what I could do to manually channel switch, but it seems I would probably have to bring down the vif I'm not using, switch channels, and then bring on the new interface, and do that continuously for multichannel to work.

I was wondering if there's any support within the firmware for this? I know STA+AP isn't supported in zephyr's SDK, but it is supported by the firmware if you use multiple virtual interfaces, as long as they are on the same channel, at least that's what I've confirmed. I just need to know if firmware is capable of rapid channel switching in a way that's usable. I can attempt to implement rapid channel switching but it seems like if it's done on the host side it will greatly impact performance and it would just make more sense for the firmware to handle this.

RE: nRF7002 STA+AP with Different Channels

Simonr — Wed, 18 Sep 2024 12:29:21 GMT

Just for reference, the AP + STA simultaneously is not yet supported as per the SoftAP documentation page here: https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/protocols/wifi/sap_mode/sap.html#supported_functionality_and_limitations, so we don't have any specific suggestions on how to implement this yet.

Best regards,

Simon

RE: nRF7002 STA+AP with Different Channels

esmart-engineering — Tue, 17 Sep 2024 16:27:34 GMT

Sorry, I had to add a callback for commands to fix a diferent issue, but there's usually a "umac_event_ctrl_process: %d cmd -> status %d" log line from event.c in nrfxlib, which is now replaced with "nrf_wifi_cmd_callbk_fn: cmd=%d status=%d" callback log line. The error is -16 when starting ap while a second interface (STA) is already up and on a different channel. Once the start_ap fails, everything past that begins to fail for ap functionality. If I turn off STA, I can run the same start ap command and it will work, so its just the STA interface causing problems.

So if I'm understanding right, I need to disable any current interfaces before starting AP, and then turn them on again after. If I do it that way then AP should be able to control the radio, correct?

I wasn't sure how radio sharing worked on the chip, but it sounds like its done manually through NRF_WIFI_UMAC_CMD_SET_CHANNEL commands, correct?

I'll try this method unless its wrong, but I'm working on different issue so it won't be testing it for another day.

RE: nRF7002 STA+AP with Different Channels

SpeedCrash100 — Tue, 17 Sep 2024 13:47:24 GMT

There are info in these logs: [13280.189384] nrf_wifi_cmd_callbk_fn: cmd=13 status=-16. I've tried to do the about a same with nrf7002. (vif 0 - AP 2.4 GHz 1 channel, vif 1 - STA 5 GHz 36 channel). And got the same: umac_event_ctrl_process: Command 13 -> status -16.
Command 13 is START_AP that's means I cannot even see AP. -16 is probably EBUSY?. This is starting point where it goes wrong.

RE: nRF7002 STA+AP with Different Channels

Simonr — Mon, 16 Sep 2024 14:02:06 GMT

This log doesn't give a lot of information in terms of error codes or where it actually is failing from what I can see, as it only reports what it is doing, and not the callbacks from any functions failing. Have you been able to figure out what function/process that is actually failing on your end, and what channels are you trying to use exactly, one 5GHz and one 2.4GHz? I can't think of why it shouldn't be able to use different channels for STA and AP as long as you switch between the two when needed.

My first guess would be that the STA is taking up the radio on its allocated channel so you're not able to disable the radio to switch channel and allow the AP to run, but we would need some error codes from the logger to be able to tell anything here.

Best regards,

Simon