A network control system configured to manage radio communication devices for a Spectrum Access System (SAS) shared spectrum wireless network is disclosed. The network control system may include a receiver to receive an estimate of a proximity to a Priority Access License (PAL) radio communication device for a plurality of user terminals. The estimate may be based on measurements of signals transmitted by the PAL radio communication device. The network control system may also include a processor configured to cause a user terminal to be configured to perform measurements based on the estimate of the proximity to the PAL radio communication device. The performed measurements may include an interference measurement indicative of interference to the PAL radio communication device from a General Authorized Access (GAA) radio communication device.