de 2.56 S 10.24 S Idle model 2.56 S 43.69 min (2621.44 s) for 413 days (9920 hr) applicable Cat-M to both Cat-M and NB-IoT 174.76 min (10485.76 s) for (timer T3412) NB-IoT 14 Internet of Things Optimization Power Saving Mode NAS registered NAS registered NAS registered RRC connected RRC idle RRC null Tracking area update (periodic) Figure 14.19 NAS and RRC states with eDRX and power saving mode (PSM). NB-loT Power Consumption Measurements In 2018 and 2019, multiple commercial NB-IoT networks and UEs were launched. Therefore, the current state of the art in terms of NB-IoT UE power consumption can be measured, and using the live NB-IoT network configuration, the battery lifetime can be estimated. The power consumption of three commercial NB-IoT UEs (Release 13) is listed in Table 14.7. The power consumption was measured in four power states using a lab test bed consisting of a Keysight UXM NB-IoT base station emulator and a power analyzer [3]. Active transmission at maximum output power is the most power consuming state, while reception requires three to six times less power. Clearly, it is important to use Connected Mode DRX during the data transfer states since it further reduces the power consumption to one tenth of the reception power state. Finally, the PSM power state has proved to be a valuable addition to the LTE IoT technologies as it is roughly 1000 times less power consuming than Connected Mode DRX. The battery lifetime estimation is based on lab measurements, but to ensure a realistic setup of the base station emulator, the network configuration of a live NB-IoT cell in Denmark was observed and used as baseline configuration. Specifically, the network configuration was collected as a function of the coverage level. This was achieved by placing a UE in a shielded box and connecting it to an outside antenna using a step attenuator. By varying the signal attenuation, the configuration for each of the three coverage enhancement levels (ECLs) was captured in [3]. The estimated battery lifetime is illustrate