There is provided a communication system in which a base station apparatus communicates with a terminal apparatus and a communication apparatus flexibly designed to address diverse use cases so as to significantly enhance the transmission efficiency of the system as a whole. The communication apparatus includes an acquisition section that acquires information from an apparatus in wireless communication, and a control section that selects either orthogonal multiple access communication or non-orthogonal multiple access communication for communication with the apparatus on the basis of the information acquired by the acquisition section.