Live energy consumption measurements show that due to different configurations during data connections, the actual energy consumption can vary between networks even though the energy estimate is the same.
Graphs Live test result for Operator A and Live test result for Operator B show the results of energy consumption measurements performed for two operators in the same geographical area using LTE-M network. The graphs show also the corresponding energy estimate values from %CONEVAL responses.
Notes for the following graphs:
- X-axis: Energy estimate value.
- Y-axis: Energy consumption where the average of energy estimate value 7 is normalized to be 1.
- Blue curve: Average of energy consumption per energy estimate value.
- Red bars: Standard deviation from the energy consumption average per energy estimate value.
Live test result for Operator A and Live test result for Operator B indicate that the average duration of a connection was 17–21 seconds for Operator A and 5–8 seconds for Operator B. The tests show that although an equal amount of data was transmitted, the duration of the average connection was much longer with Operator A. A longer connection duration means that the absolute energy consumption was higher for Operator A also when the same energy estimate values were returned for Operator A and Operator B in %CONEVAL responses. Current consumption is always higher in RRC Connected mode than in RRC Idle mode even when there is no data transmission.
The energy estimate value 6 indicates a risk of increased energy consumption whereas the energy estimate value 5 indicates a significant risk of high energy consumption. The large standard deviation of the energy estimate value 5 indicates the unpredictability of the expected energy consumption. The test results show that standard deviation is smaller in better radio conditions, which might be important in longer data sessions.
If the energy estimate value is 5, it is recommended to avoid transmitting data with devices that have issues with power consumption or with Long-Term Evolution (LTE)'s peak power levels. The nominal energy estimate value 7 is the most common value to be expected in a live environment. The nominal value is suitable for generic cellular Internet of Things (IoT) use cases, for example, short data transmission.
The duration of a data connection can be optimized with the Release Assistance Indication (RAI) feature. For more information, see Connection-related features and Release assistance indication %RAI in nRF9160 AT Commands or nRF91x1 Cellular AT Commands.
For information on the test setup used for the pedestrian use case measurements, see Appendix.