User equipment, base station, information reporting method, and information receiving method

A base station for communicating with user equipment in a radio communication system supporting carrier aggregation, the base station comprising:

• a transmitter that reports to the user equipment a plurality of bands supported by the base station;
• a receiver that receives, from the user equipment, upon the user equipment detecting that the plurality of bands supported by the base station is reported, band combination information indicating one or more band combinations for the carrier aggregation;
• and
• a processor that determines a band combination capable of being used in the user equipment depending on the one or more band combinations included in the band combination information received by the receiver,
• wherein, upon detecting that the band combination information includes highest band combination information corresponding to the band combination having the largest number of component carriers (CCs) to be combined, among the one or more band combinations capable of being used for the carrier aggregation in the user equipment, the processor determines that the user equipment is capable of using the highest band combination and all band combinations, each having a number of CCs that is less than the number of CCs in the highest band combination.

An information reporting method to be executed by user equipment for communicating with a base station in a radio communication system supporting carrier aggregation, the information reporting method comprising:

• a generation step of generating, upon detecting that a plurality of bands supported by the base station is reported from the base station, band combination information indicating one or more band combinations capable of being used for the carrier aggregation in the user equipment;
• and
• a transmission step of transmitting the generated band combination information to the base station,
• wherein the generation step generates the band combination information including highest band combination information corresponding to the band combination having the largest number of component carriers (CCs) to be combined, among the one or more band combinations capable of being used for the carrier aggregation in the user equipment.

An information receiving method to be executed by a base station for communicating with user equipment in a radio communication system supporting carrier aggregation, the information receiving method comprising:

• a reporting step of reporting to the user equipment a plurality of bands supported by the base station;
• a reception step of receiving, from the user equipment, upon the user equipment detecting that the plurality of bands supported by the base station is reported, band combination information indicating one or more band combinations for the carrier aggregation;
• and
• a determination step of determining a band combination capable of being used in the user equipment depending on the one or more band combinations included in the received band combination information,
• wherein, upon detecting that the band combination information includes highest band combination information corresponding to the band combination having the largest number of component carriers (CCs) to be combined, among the one or more band combinations capable of being used for the carrier aggregation in the user equipment, the determination step determines that the user equipment is capable of using the highest band combination and all band combinations, each having a number of CCs that is less than the number of CCs in the highest band combination.