Minimization of secrecy outage probability with single-antenna uncoordinated cooperative jamming

The problem of power allocation with uncoordinated cooperative jamming is addressed in this paper to enhance the physical layer security of the single-input-single-output wiretap channel with single-antenna jammers. Differing from the existing works concerning the secrecy rate maximization, this paper studies the problem of minimizing the secrecy outage probability with fixed secrecy rate, where the channel state information concerning the eavesdropper is only known statistically. This problem is formulated as an optimization problem of power allocation for the jamming signals. We prove that the optimization problem is convex in essence, and the optimal solution is thus conveniently obtained by using the methods of golden section search and bi-section search. Simulation results show that the proposed approach is very efficient and can significantly enhance the physical layer security by reducing the secrecy outage probability.