eDRX Mode+PSM Mode+Sleep Mode+Standby Mode+Active Mode Power Consumption

[Hardik]

Hi All,

We are developing a Smart Tracking Device using the latest module of nRF9160 and nRF51840.

We will be using an nRF9160  LTE M1 + NB1 and GNSS service for tracking a device and nRF51840 will serve only as a controller without a bluetooth.

Can you please help in calculating Power for one day from which we can analyze total power for three years.

1. Which mode will be more helpful in terms of long battery life. eDRX or PSM.

2. What can be the maximum interval of one cycle where LTE can transmit data once?

3. How long GPS will remain active in a day and how can I save battery after fetching location data.

4. Which modes are in our control where we can set timings for eDRX mode.

5. How to utilize PSM mode with how much intervals?

6. What can be the current consumptions for each mode as per one cycle where it can send data once.

Let me know if you need more info.

Kindly note we want to drive our device for atleast three years even after having multiple events so that we can select battery capacity.

Thanks

Hardik Raval

[Martin Lesund]

Hi Hardik,

1.) It depends on your application and usually how long you are going to sleep. Over 10 minutes between intervals it's usually better with PSM, but please read about the details here: https://www.gsma.com/newsroom/wp-content/uploads/CLP.28v1.0.pdf

2.) It depends on what the networks allow you to.

PSM: The maximum time a device may sleep is approximately 413 days (set by 3GPP Release 13 for T3412). The maximum time a device may be reachable is 186 minutes (an equivalent of the maximum value of the Active timer T3324).

eDRX: Maximum ~43minutes (~174minutes in NB-IoT mode)

3.) You can save battery by increasing the intervals between each time you gather the GPS data. You would not have the GPS on all the time since that will use a lot of power.

4.) You can request the intervals from the network. It is usually easier to get permission to increase the intervals than decreasing them. (here is a possible way to set the change the eDRX settings.)

5.) This can also be requested via AT commands

6.) You need to be more specific. What intervals, including GPS, how many times per day, how much data etc.

Best Regards,

Martin L