Intercept Probability Analysis of NOMA-Enabled V2V Communications Over Double-Rayleigh Fading Channels

This paper investigates the secrecy performance of a downlink non-orthogonal multiple access (NOMA) enabled vehicular communication system. In particular, we consider a setup where a source vehicle exploits power-domain NOMA to communicate securely with two legitimated user vehicles, i.e., far user and near user. A passive eavesdropper vehicle exists in the near vicinity to overhear the confidential information of both users. Based on the decoding capabilities of the eavesdropper, we formulate two cases; 1) Case I: when eavesdropper has the same decoding capability as with the user vehicles, and 2) Case II: when the eavesdropper has the decoding capability to perfectly decode the signals of user vehicles. For the considered system setup under Cases I & II, we derive the analytical expressions for the intercept probability of the individual users and overall system over double-Rayleigh fading channels. We also present the secrecy diversity order analysis of the individual users. The numerical and simulation results validate our analytical framework, and show the effects of various system/channel parameters on the system's secrecy performance.