A base station establishes a wireless connection in a first portion of a frequency band with a user equipment located in a first geographic area. The first portion is allocated to an operator of the base station in response to a request transmitted to a spectrum access server (SAS). The user equipment is handed over from the first portion to a second portion of the frequency band in response to detecting presence of an incumbent that is allocated a third portion of the frequency band for exclusive use within a second geographic area that overlaps with the first geographic area. The third portion overlaps with the first portion. The second portion is allocated to the operator in response to the request. The first portion and the second portion are separated by a frequency bandwidth that is larger than a threshold determined based on a frequency bandwidth allocated to incumbents.