nRF9160 High Bandwidth Power Consumption Evaluation

[willdeng]

Hi there, I'm trying to guesstimate the best that I can, the amount of power it would take to transmit roughly 10 kbit/s of data through LTE-M on the nRF9160. I'm just looking for ballpark numbers to see how power hungry this application would be and to see what people have experienced in the real world when transmitting data. Here is my scenario:

1. Strong LTE Signal 

2. Normal DRX at 2.56 sec to max ~5 sec (latency needs to be low in this application, would DRX be the right option?)

3. Packet size can be variable so if I need to send at intervals of 5 seconds, then the packet would be 50 kbit

Assuming that I've already connected to the network so not factoring in the power associated with that, what can I expect my nominal power consumption to be around? 

In the spec sheet, I'm seeing that an 180kbit/s uplink at 0 dBm would consume 45 mA but I'm not sure how that would scale according to the amount of data transferred. Has anyone measured current consumption when transmitting large amounts of data? If so, what was the scenario and what was the result? 

 

Best

-Will 

[Håkon Alseth]

Hi Will,

 

A quick calculation, using 2.56 sec eDRX, and uploading a 10kByte payload (UDP) every 5 seconds, shows that the average is about 27 mA, assuming 23 dBm output power.

Note that these are calculated values, and your measured might differ, as things like output power will be determined based on the signal strength of your link (eNB drives this setting), and re-transmits could also occur over-the-air.

 

Sending one payload of 1 kB every second increases average to close to 31 mA.

 

I would recommend that you setup a test to replicate your requirements and measure the usage, as the above are ballpark numbers.

 

Kind regards,

Håkon

[willdeng]

Thanks a bunch Hakon. This is super helpful in ballparking the level of power consumption that I should expect and put things in perspective.