LAUSR

This letter studies the secrecy outage probability of diversity schemes (i.e., antenna-user selection with maximal ratio combining (AUS-MRC) scheme and the user selection with space-time block coding (US-STBC)) over arbitrary (i.e., integer and real valued) Nakagami fading channels. The exact secrecy expressions of the diversity schemes is derived for integer-valued fading index expressed as a finite sum and for real-valued fading index expressed as an infinite sum. Also, the secrecy diversity order and the secrecy SNR gain of the secrecy performance for the diversity schemes are quantified for arbitrary Nakagami fading channels. The first new insight provided by this letter is that the secrecy diversity order of the diversity schemes is proportional to the fading index for arbitrary fading parameters. Also, this letter shows that the secrecy diversity order of the diversity schemes is only affected by the parameters of the diversity scheme, not by eavesdropper’s parameters for arbitrary Nakagami fading channels.