Radio transmission device, radio reception device, communication method, and communication system

A radio reception device which performs communication with a radio transmission device, the radio reception device comprising:

• a transmission unit that transmits a frame;
• and
• a reception unit that receives a frame including information indicating whether or not to start a reception operation based on a first clear channel assessment (CCA) level, and determines whether or not to perform the reception operation based on the first CCA level in a case where the information indicating whether or not to start the reception operation based on the first CCA level indicates that the reception operation is enabled, wherein
• the reception unit receives a frame including information indicating a first CCA period in which whether or not to perform the reception operation based on the first CCA level is determined, or a frame including information indicating a second CCA period in which whether or not to perform the reception operation based on a second CCA level is determined, and
• the reception unit is capable of changing the first CCA level.

A communication method of a radio transmission device which performs communication with a radio reception device, the method comprising:

• a step of performing carrier sense;
• a step of transmitting a frame including information indicating whether or not to start a reception operation based on a first clear channel assessment (CCA) level;
• and
• a step of transmitting a frame including information indicating a first CCA period in which the reception operation based on the first CCA level is possible, or a frame including information indicating a second CCA period in which a reception operation based on a second CCA level is possible, wherein
• the communication method is capable of changing the first CCA level.