Power Allocation and Jammer Selection of a Cooperative Jamming Strategy for Physical-Layer Security

In this paper, we propose power allocation (PA) and jammer selection schemes based on a cooperative jamming strategy combined with a null-steering beamforming technique (CJ-NB strategy) for physical-layer security. Using the CJ-NB strategy, we first present an asymptotic optimal PA scheme, obtained by solving an achievable secrecy rate maximization problem, and then provide the corresponding achievable secrecy rate analysis. The analysis results show that the maximum achievable secrecy rate will become asymptotically saturated if the number of jammers is large enough. To avoid waste in the use of jammers, we also provide two jammer selection schemes that can determine the minimum number of jammers necessary to achieve almost the same secrecy rate as using all jammers for the CJ-NB strategy with the asymptotic PA scheme. One has lower computational complexity, and the other achieves better performance in reducing the number of jammers used. Finally, simulation results are given to demonstrate the effectiveness of the proposed schemes.