Abstract: The prevailing research on physical layer security assumes that users are static, while takes no account of user mobility. In view of user mobility, a novel transmit antenna selection and cooperative communication design (TAS-Cop) to enhance physical layer security was proposed. The scenario considered contains two cooperative base stations, which are equipped with multiple antennas respectively. Firstly, both of the two transmitters apply TAS technology to maximize the signal to noise ratio (SNR) at the legal receiver. Next, when the legal receiver moves in the coverage of the two base stations, the transmitters cooperate with each other such that the best security performance can be acquired. Based on Rayleigh fading channel, key security metrics such as the closed-form expressions for non-zero secrecy capacity probability and secrecy outage probability were derived. Following that, an optimal power allocation strategy between the two transmitters was presented. Numerical simulation results show that the proposed scheme can achieve better security performance when compared with existing TAS schemes with user mobility is taken into consideration.

Key words: physical layer security, antenna selection, cooperative communication