Frequency selection method and cognitive wireless system

A wireless communications system comprising a database apparatus and a mobile communication apparatus, the mobile communication apparatus performing communications by selecting a frequency from among available frequencies,

• wherein the database apparatus includes circuitry configured to:
• store, for each frequency, a prohibited area which is an area where a licensed user is using radio waves;
• and
• determine, for each frequency and on the basis of location information reported from the mobile communication apparatus, a first distance, which is a distance in a first direction to the prohibited area from a location indicated by the reported location information, and a second distance, which is a distance in a second direction to the prohibited area from the location indicated by the reported location information, and generate distance information including the first distance and the second distance, and
• the mobile communication apparatus includes circuitry configured to:
• acquire location information;
• report the location information to the database apparatus and acquire the distance information;
• and
• determine a frequency to be used for communication, on the basis of the reported distance information and a direction of movement of the mobile communication apparatus.

A mobile communication apparatus which performs communication by determining a frequency to use on the basis of distance information reported from a database apparatus storing, for each frequency, a prohibited area which is an area where a licensed user is using radio waves, the mobile communication apparatus comprising:

• circuitry configured to:
• acquire location information;
• report the location information to the database apparatus and acquire distance information including a first distance, which is a distance in a first direction to the prohibited area from a location indicated by the location information, and a second distance, which is a distance in a second direction to the prohibited area from the location indicated by the location information;
• and
• determine a frequency to be used for communication, on the basis of the reported distance information and a direction of movement of the mobile communication apparatus.

A database apparatus, comprising:

• circuitry configured to:
• store, for each frequency, a prohibited area which is an area where a licensed user is using radio waves;
• and
• determine, for each frequency and on the basis of location information reported from a mobile communication apparatus, a first distance, which is a distance in a first direction to the prohibited area from a location indicated by the reported location information, and a second distance, which is a distance in a second direction to the prohibited area from the location indicated by the reported location information, and generate distance information including the first distance and the second distance.