Intra-frequency neighbours can be defined automatically as part of the normal intra-frequency handover procedure. The addition of a neighbour increases the handover signalling requirement but once added, the neighbour can be used by all other UE.
The intra-frequency handover procedure starts when the serving eNode B sends an RRC Connection Reconfiguration message which instructs the UE to start intra-frequency measurements.
The UE searches for neighbouring cells, identifies their Physical Layer Cell Identities (PCI) and measures their RSRP (and/or RSRQ). The UE then follows the instructions of the eNode B in terms of reporting, e.g. when a reporting event is triggered
The eNode B receives the neighbour cell measurements and decides whether or not the UE should complete a handover. If a handover is to be completed, the eNode B checks whether or not the reported PCI is included within its existing neighbour database.