Secrecy capacity based on suboptimal multi-antennas selection and power allocation

We propose a suboptimal multi-antennas selection (SMAS) scheme to enhance physical layer (PHY) security, due to the limitations of multi-input multi-output (MIMO) transmit antenna selection scheme in PHY security technologies. We consider that the channel state information (CSI) of wiretap channel is unknown to the transmitter, and select multi-antennas exploiting the suboptimal multi-antennas selection scheme. Next, we use water-pouring algorithm to assign the transmit power of each selected antenna at the transmitter and derive the expression of secrecy capacity. We prove the validity of the proposed scheme through simulating the received bit-error-ratio (BER) of the receiver and the eavesdropper, respectively. In contrast to the suboptimal antenna selection scheme which selects only one antenna at the transmitter, the proposed SMAS scheme selects multiple antennas and increases the secrecy capacity of the MIMO system numerically.