  Fog Radio Access Network (F-RAN) exploits cached contents at edge nodes (ENs)
and fronthaul connection to the cloud for content delivery. Assuming dedicated
fronthaul links between cloud and each EN, previous works focused on analyses
of F-RANs using offline or online caching depending whether the content
popularity is time-invariant or time-variant. Extension has been done for
multicast fronthaul link connecting cloud to only two ENs and time-invariant
popularity. In contrast, the scope of this work is on the case where multicast
fronthaul link connects arbitrary number of ENs to the cloud and content
popularity is time-variant. Normalized Delivery Time (NDT) is used as a
performance measure and by investigating proactive online caching, analytical
results reveal that the power scaling of fronthaul transmission sets a limit on
the performance of F-RAN.
