It is provided a method, comprising monitoring if a cell is being started; selecting a temporary physical cell identifier among a predefined pool; instructing the cell to adopt the selected temporary physical cell identifier if the cell is being started; determining a permanent physical cell identifier for the cell, wherein the permanent physical cell identifier does not belong to the predefined pool and is different from each used physical cell identifier, wherein the used physical cell identifiers are indicated in measurement reports; checking if a first time has elapsed after the cell has been instructed to adopt the selected temporary physical cell identifier or a second time has elapsed after the cell has been started; replacing the selected temporary physical cell identifier by the determined permanent physical cell identifier if the first time or the second time has elapsed.