CDIS is a functional entity to be a server that manages information of a plurality of secondary systems. For example, CDIS collects information about secondary systems from each secondary usage node via CE and CM. CDIS also collects information about the primary system and information about available channels from the data server 20. Then, CDIS stores collected information in a database. The information stored by CDIS is used when a decision about coexistence is made by CM. CDIS may select master CM (CM that supervises a plurality of CM and makes a decision intensively) among a plurality of CM. CDIS also has a neighbor discovery function which detects neighboring secondary systems that may interfere with each other.

At least one of the above three functional entities is implemented in each of the communication control apparatuses 30 shown in FIG. 1. Incidentally, a part of the functional entities may be implemented on the individual secondary usage nodes 40. In addition, a part of the functional entities may also be implemented in the same apparatus as the data server 20.

The above three functional entities may be arranged in each apparatus as shown, for example, in FIG. 3. The arrangement of the functional entities described here is only by way of example and other arrangements may also be used.