Reception Window Selection in EDT+ for Energy Efficient NB-IoT

Existing optimizations such as Early Data Transmission (EDT) and Improved Early Data Transmission (EDT+) improve Narrowband Internet of Things (NB-IoT) energy efficiency significantly. These improvements support battery-free or energy-harvesting NB-IoT devices and offer a promising path toward more energy-efficient deployments. In this work we consider real-world challenges that have so far not been taken into account. Specifically, when an EDT+ transmission fails, normal NB-IoT procedures are used as fallback which in turn reduces energy efficiency. In this work we present and analyse methods for dimensioning and dynamic adaptation of the base station (BS) reception window based on node clock drift and transmission schedules. Dynamic adaptation of the reception window ensures that EDT+ energy efficiency gains can be maintained while optimising channel utilisation.