A plurality of information symbols are transmitted by a carrier wave by assigning different modulation indices to the individual information symbols. Thereby the modulated carrier wave carries information not only by the digitally encoded (modulated) data words but also by the different modulation indices used for successive intervals that thus also represent information symbols. This increases the data rate of a wireless communication. When used in passive identification systems, for example transponders, the transmission of the superimposed clock information eliminates the need for the clock generation logic in the receiver. The reduced energy consumption enables the communication distance to be increased.