Modem Reset Loop Restriction Reset

RE: Modem Reset Loop Restriction Reset

Charlie — Mon, 03 Jun 2024 09:09:49 GMT

Hi Sashi,

[quote user="sashi"]Currently, we must reboot the device externally to allow it to stay connected 24/7 once we detect that it no long can connect. [/quote][quote user="sashi"]Please advice on the best way the nrf91 should be used to handle fixed installations with unlimited power and weak signals. [/quote]

For this fixed installation device, it seems reboot deice will help to improve cellular network connection according to your experience. If it is the truth, I think you can set a timer to control the reboot happens no more than 6 timers per 30 minutes. This can ensure you have at least 5 minutes interval to send data. But I would suggest work on the direction to improve connection instead of play trick with Modem Reset Loop Restriction Reset. Here are some suggestions:

Use NB-IoT network instead of LTE-M if possible.
Modify hardware design to improve antenna performance.
Switch to operator with better coverage in this area, even other cellular connection method like 4G, 5G.
Switch to other connection technology like DECT NR+, LoRa to extend connection range or the device.

[quote user="sashi"]if we have an accelerometer to detect motion, that we toggle %REDMOB between mobility and stationary mode dynamically? This would be for a generally mobile application, but when a device stops moving it will rest there for several hours to days. [/quote]

Yes, you can use the accelerometer to detect motion and dynamically toggle the %REDMOB command between mobility and stationary mode. This is particularly useful for applications where a device is generally mobile but may rest in one place for several hours to days.

The main benefits of enabling the Nordic-proprietary reduced mobility feature are:

Reduced Power Consumption: By limiting the swapping between cells in stationary use cases, the device can save power, which is crucial for battery-operated devices.
Stable Connectivity: The device stays connected to the same base station, avoiding the power consumption penalty of switching to a different base station and back. This can help maintain a stable connection, especially in scenarios where there might be a temporary drop in link quality to the closest base station.

You can use this feature if you think your application will benefit from it.

Best regards,

Charlie

RE: Modem Reset Loop Restriction Reset

Sashi — Fri, 31 May 2024 15:57:31 GMT

additionally is is recommended, if we have an accelerometer to detect motion, that we toggle %REDMOB between mobility and stationary mode dynamically? This would be for a generally mobile application, but when a device stops moving it will rest there for several hours to days.

RE: Modem Reset Loop Restriction Reset

Sashi — Fri, 31 May 2024 15:49:15 GMT

This will be very helpful. thanks

I want to understand what is the best way to handle this case
A device is placed at a location that has like 1 bar cell connection. The device can connect but the connection is poor. This device is fixed at this location and doesn't move. additionally the device is always supplied with USB power so we don't care about power consumption. Data is sent every 1-10 minutes (programable)

Currently, we must reboot the device externally to allow it to stay connected 24/7 once we detect that it no long can connect.

I think we are fine with constantly toggling going off and online every minute as we need to send data, but not sure if this preferred behavior that the cell provider wants to see.
Please advice on the best way the nrf91 should be used to handle fixed installations with unlimited power and weak signals.

RE: Modem Reset Loop Restriction Reset

Charlie — Fri, 31 May 2024 06:51:19 GMT

Hi Sashi,

There is no direct count can be readout.

You can enable AT%MDMEV=1 to get %MDMEV: RESET LOOP. Then count it at your application codes.

Best regards,

Charlie

RE: Modem Reset Loop Restriction Reset

Sashi — Thu, 30 May 2024 15:41:05 GMT

Is there a way in code to know that you have reached modem reset loop count?

RE: Modem Reset Loop Restriction Reset

Charlie — Thu, 30 May 2024 12:21:28 GMT

Hi Sashi,

Here is a more detailed explanation from our modem team:

The modem reset loop restriction serves as a safeguard against unexpected issues with the cellular modem and application. Its purpose is to protect networks in case the application or cellular modem does not behave as expected. This protection ensures that the nRF91 device does not congest the network, for example, with excessive signaling (Attach requests), which could occur if the application and modem continuously reset and attempt new connections in a loop.

There is a distinction between "reset loop protection" and "connectivity." A moving nRF91 device is not affected by the modem reset loop protection. Losing connectivity is a normal occurrence for cellular devices, and connectivity is automatically restored when possible. For mobility enhancements and power saving options, there are AT commands that could be utilized to select best possible performance for mobility and power consumption. For example see. %XCOUNTRYDATA, %CONEVAL, %XDEEPSEARCH, %PERIODICSEARCHCONF, %REDMOB and many more.

Best regards,

Charlie

RE: Modem Reset Loop Restriction Reset

Sashi — Tue, 28 May 2024 16:52:25 GMT

So what is the recovery process for a final product in the field?
If a device is placed in a location with marginal signal, will it eventually hit this counter limit and be offline forever?

RE: Modem Reset Loop Restriction Reset

Charlie — Thu, 23 May 2024 09:41:47 GMT

Hi Sashi,

Modem Reset Loop Restriction is actually used to protect your device in such condition you have entered. The keep searching and reconnect process will draw a lot of power and bring unstable connection to your high level application.

In product development phase, active reset loop restriction can be removed with the %XFACTORYRESET=0 command. The command should not be used for this purpose in the final product. If %XFACTORYRESET=0 is used, all modem data, including user-configurable data, is reset.

Best regards,

Charlie