Handover in a shared radio access network environment using subscriber-dependent neighbour cell lists

In a radio access network, a drift radio network controller (DRNC) [262] transmits to a serving radio network controller (SRNC) [261] either (1) a filtering rule for a candidate cell [so that the serving radio network controller (SRNC) can generate a measurement list for a user equipment unit having a connection controlled by the serving radio network controller (SRNC)], or (2) a list of cells qualifying [according to filtering rules stored at and applied by the drift radio network controller (DRNC)] for inclusion in the measurement list for the user equipment unit. The filtering rule provides criteria useful for determining whether the candidate cell qualifies for inclusion in the measurement list of cells for the user equipment unit. If the candidate cell is a shared cell or cell for which the user equipment unit otherwise has permission for usage, the candidate cell qualifies for inclusion in the measurement list for the user equipment unit. On the other hand, if the candidate cell is a unshared cell for which the user equipment unit has no permission for usage, the candidate cell does not qualify for inclusion in the measurement list for the user equipment unit. The filtering rule itself can take various forms, and the filtering rule-bearing Iur message can have various formats possibly with transmission economizing features of the invention. In one mode of the invention, the drift radio network controller (DRNC) may itself apply the filtering rule to determine whether the candidate cell qualifies for the measurement list. In a hybrid mode, filtering functions are initially performed by the serving radio network controller (SRNC) and subsequently performed by the drift radio network controller (DRNC).