[Object] To prevent or reduce the degradation in transmission characteristics caused by fast fading (fluorescent lamp interference) to achieve optimized throughput.[Solution] A process for detecting fast fading (fluorescent lamp interference) is performed (ST2). Fast fading is detected by, for example, detecting a variable light source whose frequency is twice the frequency of an alternating current power supply. When fast fading is detected, a frame length update process is performed (ST3, ST4). In the case of “subject transmission” in which the subject apparatus is the transmitter of a data frame, the setting of the maximum number of aggregations in frame aggregation (A-MPDU, A-MSDU) is changed to “the recommended maximum number of aggregations”. “The recommended maximum number of aggregations” is set in advance so that the UDP throughput can be maximized under the conditions where fast fading has occurred. In the case of “subject reception” in which the subject apparatus is the receiver of a data frame, the subject apparatus sends a request message for limiting the maximum transmission length to the communication counterpart apparatus.