A communication apparatus includes a receiving device configured to receive one physical frame in which a plurality of MAC frames are aggregated. This physical frame includes one acknowledgement request frame for the plurality of MAC frames. The apparatus includes an acknowledgement frame forming device configured to form an acknowledgement frame representing reception statuses of the plurality of MAC frames in response to the acknowledgement request frame. The apparatus also includes a transmitting device configured to transmit the acknowledgement frame. This acknowledgement frame includes a compressed acknowledgement frame representing an acknowledgement bitmap having a size equal to a maximum number of MSDUs (MAC Service Data Units) when one MPDU (MAC Protocol Data Unit) corresponds to one MSDU.