Multiuser transmit security beamforming in wireless multiple access channels

In this paper, we investigate beamforming approaches for multiple access secrecy channels. This paper investigates the equivalency between beamforming weight solutions under a fixed sum transmit power constraint and those under a fixed secrecy rate when multiple eavesdroppers are available. We propose an advantageous semidefinite-programming based beamforming solution for multiple eavesdroppers in multiple-access wire-tap channels.