Distributed transmission for secure wireless links in non-line-of-sight environment by joint transmitter-receiver beamforming

The authors have proposed a distributed-transmission-based secure wireless link creation scheme by providing multiple transmission routes to a destination. In the proposed scheme, the transmitted information is divided into pieces of “shared information” by a secret-sharing method, and the pieces of information are separately transmitted to the destination through different transmission routes with individually controlled antenna directivities. In this paper, we focus on the performance of the proposed scheme in a non-line-of-sight (NLOS) propagation environment and propose a joint receiver beamforming in accordance with the controlled transmitter antenna directivity. The computer simulations clarify that the degree of spatial distribution of the transmission routes is enhanced by the joint beamforming. Therefore, it can improve the secrecy of the transmitted information by the distributed transmission in the wireless space.