Among destination terminal apparatuses to which a plurality of data signals are to be transmitted, a control unit specifies a terminal apparatus to which a known signal, whose number of streams is greater than the number of streams for a data signal, is to be transmitted. The control unit appends a known signal, whose number of streams is greater than the number of streams for this data signal, to the data signal which is to be transmitted to the specified terminal apparatus. While assigning the data signal, to which the known signal has been appended, to a posterior part of the plurality of data signals, the control unit generates packet signals in a manner that a known signal, whose number of streams corresponds to the number of streams for a data signal in a header portion, is appended to a header portion of the plurality of data signals.