Techniques for controlling spectrum usage of a hierarchical communication system

An access point (AP) device for controlling spectrum usage of a hierarchical communication system, in which a spectrum reserved for an Incumbent is usable by at least one user equipment (UE) for transmission when the spectrum is free of a transmission reservation by the Incumbent, the AP device comprising a processor configured to:

• receive a message from the Incumbent requesting vacating of a spectrum;
• generate a group of users affected by the message from the Incumbent requesting vacating of the spectrum;
• and
• perform a spectrum management operation on the group of users;
• wherein generating the group comprises assigning a group ID to a plurality of users affected by the message from the incumbent requesting vacating of the spectrum.