5G defines a new connection mode known as MICO to support IoT device connections. Some of the IoT devices would be requiring uplink only mode. I meant to say only UE can initiate radio connection when it has some data to deliver. If this mode is enabled of an UE then network (AMF) won't perform paging for that UE in the CM-IDLE state and send failure to other end of the network with the appropriate cause.
Here, one point needs to be remembered that while performing registration with the MICO mode, network assigns the whole service area to the UE because network can't perform any signalling towards such kind of UE and there is no optimization required in that context compare to the LTE core network which performs many optimization schemes for tracking area management.
