Transmit Antenna Selection with Alamouti Scheme in MIMO Wiretap Channels
This addresses security vulnerabilities in wireless communications for scenarios with passive eavesdroppers, but it is incremental as it builds on existing TAS and Alamouti methods.
The paper tackles the problem of enhancing physical layer security in MIMO wiretap channels without eavesdropper CSI by proposing a transmit antenna selection scheme combined with the Alamouti scheme, resulting in lower secrecy outage probability compared to a single TAS scheme above a specific SNR threshold.
This paper proposes a new transmit antenna selection (TAS) scheme which provides enhanced physical layer security in multiple-input multiple-output (MIMO) wiretap channels. The practical passive eavesdropping scenario we consider is where channel state information (CSI) from the eavesdropper is not available at the transmitter. Our new scheme is carried out in two steps. First, the transmitter selects the first two strongest antennas based on the feedback from the receiver, which maximizes the instantaneous signal-to-noise ratio (SNR) of the transmitter-receiver channel. Second, the Alamouti scheme is employed at the selected antennas in order to perform data transmission. At the receiver and the eavesdropper, maximal-ratio combining is applied in order to exploit the multiple antennas.We derive a new closed-form expression for the secrecy outage probability in nonidentical Rayleigh fading, and using this result, we then present the probability of non-zero secrecy capacity in closed form and the ε-outage secrecy capacity in numerical form. We demonstrate that our proposed TAS-Alamouti scheme offers lower secrecy outage probability than a single TAS scheme when the SNR of the transmitter-receiver channel is above a specific value.