Information Security and Freshness for UAV-jammer Assisted Cognitive Relay System and Optimization

To integrate physical layer security and information freshness, this work first proposes the concepts of secure age of information (SAoI) and secure peak AoI (PAoI). Then, four optimizing policies are proposed as well as the suboptimal framework and solutions. The first is the secure PAoI (SPAoI) threshold-constrained Min-PAoI policy, which minimizes the average PAol at the legitimate destination by assuming the SPAol is greater than a threshold. The second is the Max-SPAoI policy which maximizes the average SPAoI. The third is the Max-SPAoI-EC ratio policy which maximizes the ratio of SPAoI to UAV energy consumption (EC). The final one is the SPAoI threshold-constrained Min-WS-PAoI-EC policy, which minimizes the weighted sum of PAoI and UAV EC. The last two policies are energy-efficient. The simulations show that the Min-PAoI policy has the largest range of UAV flights. Both Min-PAoI and Min-WS-PAoI-EC policies have smaller SPAoI, but the two policies achieve the fresher status update. The Min-WS-PAoI-EC policy is more promising because of the low PAoI, security guarantee, and high energy efficiency.