Power Consumption Trade-Offs in Secure and Reliable NB-IoT Communication: A Comparative Study of Protocol Configurations

Low-power wide-area network (LPWAN) technologies, such as Narrowband IoT (NB-IoT), enable long-range, battery-powered communication for a wide range of applications-from smart cities to healthcare. These use cases place different demands on reliability, security, and energy efficiency. In this study, we systematically evaluate the power consumption impact of adding encryption and message acknowledgments to IoT communication over NB-IoT. We compare baseline UDP transmissions to variants including AES encryption, Datagram TLS (DTLS), TCP, and application-layer acknowledgments. Measurements were conducted on a Nordic nRF9161 development board over a commercial NB-IoT network, with high-resolution power profiling and controlled long-duration testing. Our findings show that the energy cost of encryption is negligible compared to that of wireless transmission-even with longer pay-loads-making it effectively “free” from an energy standpoint. Reliable delivery adds approximately $14-19 {\%}$ overhead, with TCP offering robustness and ease of use compared to manual acknowledgment schemes. These results support the adoption of secure and reliable protocols in energy-constrained NB-IoT deployments, with minimal trade-offs in power consumption. This work contributes to the development of optimized communication strategies for next-generation LPWAN applications, ensuring both security and energy efficiency in smart systems.