AWS IOT over Cellular and Wifi

[coltonh87]

HI,

I've got a project that needs to connect to AWS IOT over either cellular (using the nrf91) or Wifi (using the nrf7002 with the nrf53). The device will need to connect with either the Cell or Wifi on a dynamic and unpredictable basis.

There are code examples for connecting to AWS on the NRF91 and the NRF70 (with the nrf5340 as the host) but are there any examples of using the nrf53 as the host and taking care of the lower layers via nrf70/nrf91?

[Øyvind]

Hello, could you please elaborate what exactly you are trying to achieve? 

Could the use of Serial LTE Modem be a solution for you? This way the nRF53 will be main MCU, then the nRF91 will work as a modem only. 

Kind regards,
Øyvind

[coltonh87]

Hi, thanks for your reply.

Essentially I'd like this sample: sdk-nrf/samples/net/aws_iot at main · nrfconnect/sdk-nrf · GitHub to work on a PCB that has the nrf91, nrf53 and nrf70 all on it. What would be your recommended approach? 

In the above sample it can be compiled to run on either a cellular or wifi device, but i'd like it to run on both and switch dynamically during runtime.

[Øyvind]

Here is the answer from our developers

The samples/net/aws_iot sample supports Wi-Fi and LTE depending on the board that it is built for.

The sample supports the nRF7002 DK which uses the 53 as host and 7002 that implements lower level wifi protocol, for LTE it uses the 91DK. (91 sip by it self)

7002: Memory size might be an issue if the user intends to add a lot of custom logic. Partly do to RAM requirements of the Wi-Fi stack and MBEDTLS needing to run on the application core.

91: A lot more leeway due to the IP stack (TCP/IP and TLS) running on the modem.

Kind regards,
Øyvind

[coltonh87]

Thanks for your reply.

Unfortunately that doesn't help too much. Can the sample be built to support both at run time, use the 91 SIP for the cellular side and the 7002 for the wifi side?

[Øyvind]

The current version does not support both at run time. The sample uses the Zephyr NET connection manager API, which can handle concurrent network interfaces, so in theory, yes. Unfortunately, non of our developers have tested this and can't verify if it will work. I am trying to find some more answers, but it might be quicker for you to ask in the Zephyr community on Discord for more information on Zephyr specific API.