Sure fire way to determine mobile network registration?

tedhavelka66

I recently posted a network registration question here, whose answer may be able to get me past a blocking point. Do you know of a sure fire way to query an LTE modem, connecting to an LTE-M type network for its network registration status?

On my recent post I amended it, which ended up creating a reply there. Not sure whether that automatically marks my post as answered. In case that’s so I thought better to err and ask again.

I ask specifically about LTE modem network registration given Nordic Devzone engineer’s comment in Devzone ticket 87734. Power Savings Mode (PSM) is negotiated during device registration with the network. Given latest observations of my hardware and firmware I am now unsure whether my nRF9160 based device is registering with a network.

jaredwolff

@tedhavelka66 you can always run the at_client firmware. The the auto commands should request the info you’re looking for when you click the AT+CFUN=? command. I recall that you’re using AT commands so that’s your best bet besides looking at the AT command manual for the nRF9160.

https://infocenter.nordicsemi.com/pdf/nrf91_at_commands_v2.1.pdf

tedhavelka66

Hi jaredwolff ,

Thank you for the quick response! I have been referencing and using AT commands from Nordic Semi’s on-line and PDF command reference manual, heavily since you first cued me to at_cmd_write() in a post three or four months ago. I cannot locate that post now! :/ I see however that you shared same knowledge with developer Joe Bambino in CicuitDojo discussion 116 back in 2021 April.

For a time initially I was relying on AT+COPS? and AT+CGDCONT? as indicators of mobile network registration success. I thought or assumed that when AT+CGDCONT? returned the name of our SIM card maker, e.g. Hologram, iBasis, Telenyx, that that was a sign we’d registered. Past two weeks given my inability to be granted any PSM values in the greater Portland, Oregon region on U.S. west coast I question whether I’m actually connecting to a celular network.

I’d made that assumption originally as I always observed SIM card names and IPv4 numbers come back from CGDCONT when our device was able and sending short MQTT messages to an AWS cloud account. That command would report back zeroes and empty strings in seemingly the same fields when I put the modem into flight mode (AT+CFUN=4) or turned the modem off bluntyly (AT+CFUN=0).

In the AT command reference manual I’ve searched and reviewed many tens of commands there. I have focused moreso on the two document sections:

None of the commands in either of these sections, nor the others I have seen in Nordic sample apps and other communities’ forum posts seem to report whether the LTE modem has successfully registered with an MNO.

Is this phrasing correct, “to register with a Mobile Network Operator”?

I’m sorry for the verbose reply. If another member here has experience with this issue and may offer a solution I want to make it clear where I have tread so far.

I’ll continue to search. I’ve asked this question at Nordic Devzone also. Maybe i need to ask again with a little different wording.

Thanks again for your help, Jared. I’ll update here if a solution reaches me from Devzone or elsewhere.