A base station serving UE(s) receives validity time information for cell(s) formed by other base station(s). The validity time information indicates at least a time period when corresponding cells are available for use by the UE(s). The base station determines action(s) to perform for the UE(s) based on the validity time information. A UE receives, from a base station, validity time for cell(s) formed by other base station(s). The UE performs action(s) based on the validity time of the cell(s).