Cooperative Jamming for Secure Communications With Extra Power Penalty

This paper considers cooperative jamming (CJ) to ensure secure communication between the transmitter and the legitimate receiver. CJ serves as an effective and promising way to confuse the eavesdropper. However, in the presence of the CJ, the secrecy capacity is obtained at a certain cost of power, which consists of two parts: one part is the extra power consumed by transmitting CJ, and the other part is the signal-to-noise ratio (SNR) loss caused by imperfect CJ cancellation at the authorized receiver, which can be equivalent to the wasted power of the desired signal. In this paper, we both take into account the imperfect CJ cancellation and the extra power penalty to analyze the secrecy capacity, which can be a measurement of system security performance. Numerical simulation is adopted, revealing that the proposed scheme reduces the proportion of power used to transmit jamming signals, and achieves almost the same secrecy capacity as the case which does not take the extra power penalty into consideration. Moreover, the channel capacity of the desired signal is improved.