3GPP has recently introduced NB-IoT, a new mobile communication standard offering a robust and energy-efficient connectivity option to the rapidly expanding market of the Internet-of-Things (IoT) devices. To unleash its full potential, end devices are expected to work in a plug-and-play fashion, with zero or minimal configuration of parameters, still exhibiting excellent energy efficiency. We performed the most comprehensive set of empirical measurements with commercial IoT devices and different operators to date, quantifying the impact of several parameters to energy consumption. Our findings prove that parameters’ settings do impact energy consumption, so proper configuration is necessary. We shed light on this aspect by first illustrating how the nominal standard operational modes map into real current consumption patterns of NB-IoT devices. Furthermore, we investigated which device-reported metadata metrics better reflected performance and implemented an algorithm to automatically identify device state in the current time-series logs. We worked with two major western European operators to provide a measurement-driven analysis of energy consumption and network performance of two popular NB-IoT boards under different parameter configurations. We observed that energy consumption is mostly affected by the paging interval in connected state, set by the base station. However, not all operators correctly implement such settings. Furthermore, under the default configuration, energy consumption in not strongly affected by packet size nor by signal quality, unless it is extremely bad. Our observations indicate that simple modifications to the default parameters’ settings can yield great energy savings.

中文翻译：

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凭经验剖析NB-IoT设备的能耗

3GPP最近推出了NB-IoT，这是一种新的移动通信标准，可为快速发展的物联网（IoT）设备市场提供强大而节能的连接选项。为了充分发挥其潜力，终端设备有望以即插即用的方式工作，参数配置为零或最小，仍然具有出色的能源效率。迄今为止，我们对商用物联网设备和不同的运营商进行了最全面的实证测量，量化了多个参数对能耗的影响。我们的发现证明，参数的设置确实会影响能耗，因此必须进行正确的配置。我们首先通过说明名义标准操作模式如何映射到NB-IoT设备的实际电流消耗模式来阐明这一方面。此外，我们调查了哪些设备报告的元数据指标可以更好地反映性能，并实施了一种算法来自动识别当前时间序列日志中的设备状态。我们与两家主要的西欧运营商合作，以不同参数配置对两种流行的NB-IoT板的能耗和网络性能进行了测量驱动的分析。我们观察到，能耗主要受基站设置的连接状态下寻呼间隔的影响。但是，并非所有的操作员都能正确实施此类设置。此外，在默认配置下，除非非常糟糕，否则能耗不会受到数据包大小或信号质量的强烈影响。