Green Jamming Power Control for Secure OFDMA in Industrial IoT.

To understand the potential threat of the energy-efficient jamming attacker in a secure orthogonal frequency division multiple access (OFDMA) based industrial internet of things (IIoT) network, in this work, we investigate the optimal jamming to IIoT users under limited power constraint. In particular, we design an optimization problem to maximize the attacker energy-efficiency (AEE) by jointly optimizing the power allocation over the subcarriers of the IIoT users. To realize its globally optimal solution, first, we formulate an equivalent optimization problem by converting the original fractional objective function into a parametric subtractive concave function. Thereafter, the optimal point is obtained using a superlinear fast converging iterative algorithm based on Dinkelbach method that exploits Karush-Kuhn-Tucker (KKT) conditions. Via numerical results, we obtain various insights on the system performance with respect to the system parameters and lastly, the jointly optimal scheme is compared with other benchmark jamming strategies to quantify the performance.