On the Security Gap of Convolutional-Coded Transmit Antenna Selection Systems

In this work we evaluate the security gap of a network composed of two legitimate nodes and one passive eavesdropper, all of them provided with multiple antennas. We consider that transmit antenna selection (TAS) along with frame scrambling is adopted at the transmitter node, while both legitimate and malicious receivers operate under the maximum ratio combining (MRC) protocol. By considering a quasi-static fading scenario, we evaluate (analytically and through numerical results) the security gap in terms of both outage probability and frame error rate (when using convolutional codes), showing that in both situations it is possible to achieve negative security gaps using a feasible number of antennas.