Information-guided randomization for wireless physical layer secure transmission

Security capacity improvement is always the implementation goal of physical layer security, which can be achieved by deliberate randomization based on differentia and uniqueness of wireless channels through signal processing method. An information-guided randomization secure transmission scheme is proposed combined with a spatial modulation system in which information can be carried by receiving antennas index but actually by channel differentia. Randomization is generated along with channel modulation procedure realized by corresponding preprocessing to transmitting signals. We provide three approaches for designing preprocessing weights under different constraint conditions. The former two can only be used when the number of receiving antennas is less than transmitting and have a tradeoff with varying degrees between receiving performance and security. The third one then relaxes the limits via generalized spatial modulation and can be used for arbitrary antennas configuration but with a receiving performance compromise. Lastly, results of performance analysis and numerical evaluation show that the proposed secure scheme is effective to prohibit the eavesdropper from intercepting information.