Secrecy Capacity of SWIPT-Based Cognitive Satellite-Terrestrial Network With Artificial Noise and Noncolluding ERs

In this article, we investigate the security of a cognitive satellite-terrestrial network that seamlessly integrates simultaneous wireless information and power transfer (SWIPT). The network comprises a secondary system that employs the sophisticated multiple-input multiple-output SWIPT technology. Within shared spectrum, the secondary network's primary objective is to transmit confidential messages to a legitimate receiver (Bob), all the while providing energy to multiple energy receivers, which may act as eavesdroppers. Beamforming techniques and artificial noise schemes are employed to enhance transmission specifically to Bob. The ergodic secrecy capacity (ESC) with the Gauss-Laguerre quadrature approximation method is analyzed. Moreover, the asymptotic results for ESC are investigated including the slope and power offset under high signal-to-noise ratios. Finally, Monte Carlo simulations are presented to affirm the precision and accuracy of the derived analytical models and the proposed analysis.