However, unlike in the configuration depicted in FIG. 2, the wireless device 10 in accordance with the first embodiment generates the values of the symbols of artificial noise series according to transmission data, i.e., does not randomly generate such values. Thus, artificial noise series generated by the wireless device 10 are non-Gaussian distribution signals. In addition, there are correlations between a plurality of signals combined by the signal combiner 13. Specifically, there are correlations between data S and an artificial noise AN1, and there are also correlations between artificial noises AN1 and AN2. Hence, it will be difficult to separate data S and the artificial noises AN1 and AN2 from each other by using the ICA.
FIG. 8 illustrates an example of an effect achieved in accordance with the first embodiment. In this example, artificial noise series AN1 and AN2 are generated in the configuration depicted in FIG. 5 by using the method illustrated in FIG. 7. QPSK is used as a modulation scheme. A threshold CS-AN used in the process of generating the artificial noise AN1 from data S is 0.5. A threshold CAN-AN used in the process of generating the artificial noise AN2 from the artificial noise AN1 is 0.9.
