Question: In a Distributed PCI Assignment scenario for an eNodeB (eNB), what is a valid method for the eNB to restrict the list of Physical Cell Identifiers (PCIs) signaled by Operations, Administration, and Maintenance (OAM), before selecting one?
Option 1: Only through manual configuration by the network administrator.
Option 2: By analyzing uplink transmission patterns from attached User Equipment (UEs).
Option 3: Based on PCI values reported over the S1 interface by the Mobility Management Entity (MME).
Option 4: By removing PCIs that are: a) reported by UEs; b) reported over the X2 interface by neighboring eNBs; and/or c) acquired through other implementation-dependent methods.
Explanation: In a Distributed PCI Assignment scenario, the eNB refines the list of potential PCIs provided by OAM to minimize conflicts. This is done by excluding PCIs that are already in use nearby, as indicated by reports from UEs (to avoid UE-detected conflicts), neighboring eNBs via the X2 interface (for inter-cell coordination), and possibly through direct monitoring of downlink signals. This approach ensures efficient and conflict-minimized PCI selection.