Automatic building of neighbor lists in mobile system

In a radio access network ( 24 ) a femto radio base station ( 28 f) comprises a resident receiver ( 54 ) which acquires system information broadcast in a radio access network ( 24 ). At least part of the system information is used for building, at the femto radio base station ( 28 f), a neighbor data structure ( 59 ) comprising information for neighboring cells. The neighbor data structure ( 59 ) is then used for building a neighbor list. The neighbor list is subsequently transmitted from the femto radio base station ( 28 f) to a user equipment unit ( 30 ) served by the femto radio base station ( 28 f). In some example embodiments and modes, the femto radio base station ( 28 f) reports the neighbor data structure to a network node ( 26, 100 ) other than the femto radio base station.; The other node ( 26, 100 ) uses the neighbor data structure for building the neighbor list at the other node. In some example embodiments and modes, acquisition of the system information comprises scanning a surrounding macro coverage area of the femto radio base station for obtaining cell identity information for detected cells. In other example embodiments and modes, the acquisition of the system information can additionally comprise camping on a macro cell and using/consulting at least one system information block in the camped-on macro cell is consulted/used for obtaining information about at least one neighboring cell.