  The 5G New Radio (NR) standard for wireless communications supports the
millimetre-wave (mmWave) spectrum to yield unprecedented improvement of the
access network capacity. However, intermittent blockages in the mmWave signal
may degrade the system performance and lead to the under-utilisation of the
allocated resources. To circumvent this problem, the transmission slot-time
shall be adjusted according to the blockage condition, avoiding the resource
under-utilisation. In this paper, we propose that the 5G NR flexible numerology
should be applied to adapt the slot-time in order to mitigate the blockage
effects. We validate this claim by analysing the expected data rate of a mmWave
system, under a range of blockage scenarios. We show that different blockage
scenarios may require different numerologies to produce best performance, and
that the correct choice of numerology may improve this performance by as much
as hundreds of Mbps. Our results carry insights important for the design of
blockage-aware scheduling mechanisms for 5G.
