How to reduce power consumption in mqtt_simple project with small keep alive

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Didrik Rokhaug — Wed, 22 Apr 2020 07:59:43 GMT

With eDRX, you will also turn off the radio for a longer interval than normal (though not as long as with PSM).

The smallest "eDRX interval" that you can configure is 5.12 seconds.

If that (or longer) is acceptable, then yes, you can use eDRX, but then it does not make sense to send keep-alive messages every 5 seconds.

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Nikunj — Wed, 22 Apr 2020 07:14:14 GMT

hello Didrik,

Could we solve this issue by edrx?

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Didrik Rokhaug — Fri, 17 Apr 2020 13:25:08 GMT

In order to reduce the latency, you must stay in RRC connected mode. However, that means that you are listening on the radio, which means higher power consumption.

Most of the power saving features in the network are ways for the device to turn off the radio for longer periods of time. However, this naturally increases the expected latency.

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Nikunj — Fri, 17 Apr 2020 12:22:49 GMT

Hello Didrik Rokhhaug,

The reason behind low latency is that there is sensitive switch connected with device which needs to be trigger quick once user commands from server.

The user can send command any time from server that's why send data is frequent.

Thanks,

Nikunj

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Didrik Rokhaug — Fri, 17 Apr 2020 11:02:32 GMT

Hi, and sorry for not being able to reply faster.

Did you try to subscribe to +CSCON notifications?

Did the show that the device enters RRC idle mode?

If not, and with data transmission every 5 seconds, I am not really aware of how you can lower the power consumption.

At least not if you want to maintain a low latency on downlink packages (from a server to the device).

Why do you send data to the device frequently, and why do you need low latency?

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Nikunj — Thu, 16 Apr 2020 12:37:26 GMT

Hello Nordic Community,

I found the issue during just next to manufacturing phase. Is there any alternative for faster message transfer(from broker to device) with lower power consumption?

any suggestion regarding this would be helpful. I am just using default mqtt_simple code with 5 seconds keep alive period on own mqtt broker. The reason behind 5 second is faster messages are transfer, any other alternative I can also try.

How can I suppose to reduce current consumption?

Thanks,

Nikunj

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Nikunj — Tue, 14 Apr 2020 13:40:12 GMT

Thanks for reply Didrik,

I am using vodafone ireland SIM for connection.

I need faster message transfer from server to device for that I used 5 seconds.

Is there any other alternative for faster message transfer?

Thanks,

Nikunj

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Didrik Rokhaug — Tue, 14 Apr 2020 12:01:03 GMT

Hi.

One possible reason for not seeing a drop in the current consumption is that the device does not enter RRC idle mode. How long it takes to enter RRC idle depends on the network, but 5 seconds might not be enough time to be released from the network.

You can see if your device enters RRC idle by using the +CSCON AT command to subscribe to connection status notifications.

Best regards,

Didrik

RE: How to reduce power consumption in mqtt_simple project with small keep alive

Nikunj — Fri, 10 Apr 2020 12:18:13 GMT

Thanks for suggestion hkarthik97

Message is transmitted from mqtt broker to nRF9160 device so I can not put nRF9160 into sleep mode.

Thanks,

Nikunj

RE: How to reduce power consumption in mqtt_simple project with small keep alive

hkarthik97 — Fri, 10 Apr 2020 11:59:32 GMT

Did u try to put your unit to sleep when it is not transmitting data?