An Energy-Efficient Multi-Modal IoT System Leveraging NB-IoT and BLE

A multitude of wireless communication technologies are available for building Internet of Things (IoT) solutions, ranging from Low Power Wide Area Network (LPWAN) technologies with large coverage and low data rates to Wireless Personal Area Network (WPAN) technologies with shorter range but higher data rates. To satisfy the requirements of more challenging and dynamic IoT use cases, a combination of different technologies might be the best choice. Leveraging on a communication architecture that supports such multi-modal IoT systems, this paper studies the energy efficiency of a prototype device that is able to switch between Narrowband Internet of Things (NB-IoT), an LPWAN technology, and Bluetooth Low Energy (BLE), a WPAN technology. Starting from the energy consumption of the individual technologies, the overall consumption of the multi-modal device is assessed, including the effects of switching, and a prediction of the battery lifetime is made for different application contexts. Our analysis shows that for energy-critical applications, BLE is preferable over NB-IoT wherever possible. However, in case BLE is unavailable, a switch to NB-IoT can be initiated. Based on our findings, a number of approaches to use the multi-modal system in an energy efficient way has been proposed.