Radio resource management apparatus

A radio resource management apparatus used in a system in which a base station communicates with multiple mobile stations in accordance with orthogonal frequency division multiple access, multiple mobile stations modulate channel-quality-indicator reports by different cyclic shift codes for reporting channel quality indicators corresponding to reception qualities at the mobile base stations to the base station, respectively, and uplink the modulated channel-quality-indicator reports by using resource units specified by frequency and time, the radio resource management apparatus managing radio resources used for the channel-quality-indicator reports, the radio resource management apparatus comprising:

• a resource unit group designator adapted for newly designating, when a communication newly occurs between the base station and a mobile station, an uplink resource unit group in a frequency band having periodicity, so that the mobile station uses the uplink resource unit group for sending a channel-quality-indicator report periodically;
• a cyclic-shift-code allocator adapted for newly allocating a cyclic shift code to the channel-quality-indicator report from the mobile station to the base station with respect to the designated resource unit group, in accordance with a predetermined order of precedence, multiple cyclic shift codes being arranged in the predetermined order of precedence that is different from a cyclic generation order of the cyclic shift codes and that is different from a reverse order of the cyclic generation order;
• a cyclic-shift-code releaser adapted for releasing the cyclic shift code allocated to the channel-quality-indicator report from the mobile station to the base station when the communication between the base station and the mobile station has ended or been disconnected;
• a used cyclic-shift-code storage unit for storing multiple used cyclic shift codes allocated by the cyclic-shift-code allocator with respect to the designated resource unit group in such a manner that the used cyclic shift codes are associated with mobile stations to which the used cyclic shift codes are allocated;
• and
• a latest-allocated cyclic-shift-code storage unit for storing a latest allocated cyclic shift code allocated latest by the cyclic-shift-code allocator,
• wherein the cyclic-shift-code allocator is adapted for newly allocating a new cyclic shift code to a channel-quality-indicator report from a mobile station to the base station for a communication that newly occurs between the base station and the mobile station, the new cyclic shift code having a precedence ranking that is lower than a precedence ranking of the latest allocated cyclic shift code allocated latest by the cyclic-shift-code allocator for a channel-quality-indicator report from another mobile station, the new cyclic shift code being not used for channel-quality-indicator reports from other mobile stations among cyclic shift codes for the resource unit group, and the new cyclic shift code having a highest precedence ranking in the predetermined order of precedence.