An electronic device, a base station, and a method for managing a shared spectrum. The electronic device includes a processor configured to cause the electronic device to obtain coexistence measurement reports (CMRs) from the plurality of BSs; identify interference relationships among the plurality of BSs based on the CMRs; assign a set of BSs to one or more basic allocation units (BAUs) in a plurality of BAUs based on the interference relationships; and transmit a spectrum access grant (SAG) to the set of BSs, wherein the SAG includes BAU assignments for the set of BSs. Each BAU in the plurality of BAUs is a time/frequency unit and the set of BSs includes a primary BS and a secondary BS. The secondary BS can transmit in the one or more BAUs when a transmission of the secondary BS does not interfere with a transmission of the primary BS.