nRF9151 + nRF7002: Wi-Fi STA when available, LTE fallback otherwise — latest NCS guidance?

[AkbarShah]

Hi Nordic team,

I’m building a device that uses nRF9151 for cellular and an nRF7002 companion for Wi-Fi. My requirement is simple:

• If a known Wi-Fi network is available, connect in station mode and send data over Wi-Fi.

• If Wi-Fi isn’t available (or drops), fall back to LTE on the nRF91 and send the same data.

• Only one interface active at a time; no simultaneous Wi-Fi + LTE.

I’ve seen older forum threads that suggested Wi-Fi scan support was available, but STA connectivity was limited at the time. Could you please confirm the current state and best practice on the latest NCS?

Specifically, I’d appreciate guidance on:

1. Wi-Fi STA support with nRF91 host

   • Is full Wi-Fi station mode (connect, DHCP, TLS sockets) supported with nRF9151/nRF9160/nRF9161 acting as the host for nRF7002 in the latest NCS?

   • Any known limitations (throughput, concurrency with LTE modem powered but idle, RAM/flash footprint)?

2. Network interface control

   • Recommended way to bring one interface up and the other down (Zephyr net_if + net_mgmt), so only one stack is active and drawing power.

   • Event hooks to detect Wi-Fi association loss and cleanly switch to LTE, then periodically retry Wi-Fi.

3. Sockets & TLS

   • For LTE we use the modem offloaded sockets; for Wi-Fi we use Zephyr net sockets. Is the BSD sockets API seamless enough for a single app layer, or are there API differences I should account for?

   • Guidance on handling TLS credentials (modem key store vs. app/mbedTLS) so the same endpoint can be reached over either bearer.

4. Power and coexistence

   • Recommended sequence to power down nRF7002 when on LTE and vice versa (sleep/PS modes, GPIO power domains).

   • Any coexistence considerations if LTE is camped but we’re using Wi-Fi (even though not simultaneously passing data)?

This is a hard requirement for my product, so I’d like to align with Nordic’s recommended architecture and known-good examples before I lock the design.

Thanks in advance for any pointers and gotchas.

Regards,
Akbar Shah

[dejans]

Hi,

I will look into your questions during next week.
I expect to get back to you by the end of next week.

Best regards,
Dejan

[dejans]

Hi,

At present, we do not support full Wi-Fi (STA mode connectivity) in nRF9151 which has a total of 256kB of RAM and 1MB Flash. Wi-Fi feature support documentation webpage shows that there is currently no support for Wi-Fi STA mode on nrf91 Series. Instead of nrf9151, it is recommended that you use nRF54LM20. For availability, please contact your regional sales manager.

General memory requirements for Wi-Fi applications in station mode can be found in the documentation.

Powering nrf7002 up/down can be done from the host dynamically. For reference, Supply system alternatives provide information how this can be done using nrf5340.

Best regards,
Dejan