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In this paper, we focus on the use of Low-Eart Orbit (LEO) satellitesproviding the Narrowband Internet of Things (NB-IoT) connectivity to theon-ground user equipment (UEs). Conventional resource allocation algorithms forthe NBIoT systems are particularly designed for terrestrial infrastructures,where devices are under the coverage of a specific base station and the wholesystem varies very slowly in time. The existing methods in the literaturecannot be applied over LEO satellite-based NB-IoT systems for several reasons.First, with the movement of the LEO satellite, the corresponding channelparameters for each user will quickly change over time. Delaying the schedulingof a certain user would result in a resource allocation based on outdatedparameters. Second, the differential Doppler shift, which is a typicalimpairment in communications over LEO, directly depends on the relativedistance among users. Scheduling at the same radio frame users that overcome acertain distance would violate the differential Doppler limit supported by theNB-IoT standard. Third, the propagation delay over a LEO satellite channel isaround 4-16 times higher compared to a terrestrial system, imposing the needfor message exchange minimization between the users and the base station. Inthis work, we propose a novel uplink resource allocation strategy that jointlyincorporates the new design considerations previously mentioned together withthe distinct channel conditions, satellite coverage times and data demands ofvarious users on Earth. The novel methodology proposed in this paper can act asa framework for future works in the field.

NB-IoT via LEO satellites: An efficient resource allocation strategy for uplink data transmission