From the main documentation of the LTE module (Radio Link Failure)
"With the current model, an UE that experiences bad link quality will just stay associated with the same eNB, and the scheduler will stop allocating resources to it for communications. This is also consistent with the fact that, at this stage, only handovers explicitly triggered within the simulation program are supported (network-driven handovers based on UE measurements are planned only at a later stage)."
The part in red should be removed since network-driven handover is available now.
Thanks,