On the Random Access Procedure of NB-IoT Non-Terrestrial Networks

The standardization of the 5G systems has recently
entered in an advanced phase, where non-terrestrial networks
will be a new key feature in the upcoming releases. Narrowband
Internet of Things (NB-IoT) is one of the technologies that will
address the massive machine type communication (mMTC) traf-
fic of the 5G. To meet the demanding need for global connectivity,
satellite communications can provide an essential support to
complement and extend the NB-IoT terrestrial infrastructure.
However, the presence of the satellite channel comes up with new
demands for the NB-IoT procedures. In this paper, we investigate
the main challenges introduced by the satellite channel in the
NB-IoT random access procedure, while pointing out valuable
solutions and research directions to overcome those challenges.