Coordinated spectrum allocation and de-allocation to minimize spectrum fragmentation in a cognitive radio network

An apparatus comprising:

• at least one processor;
• and
• at least one memory including computer program code, the at least one memory and the computer program code configured, with the at least one processor, to cause the apparatus at least to
• define priorities for use of one or more frequency resources for a first network operating entity and one or more second network operating entities individually, the first network operating entity operating a first part of one of more radio access networks and each of the one or more second network operating entities operating a respective second part of the one or more radio access networks;
• and
• allocate and/or de-allocate at least one of the one or more frequency resources for the first network operating entity for use in the first part of the one or more radio access networks based on the priorities,
• wherein fragmentation probability information is used to define the priorities, and
• wherein the fragmentation probability information depends on overlapping between the first part of the one or more radio access networks and at least one second part of the one or more radio access networks.