Low-Complexity Transmit Power Control for Secure Communications in Wireless-Powered Cognitive Radio Networks

Area of Science:

• Wireless communication
• Network security
• Energy harvesting

Background:

• Cognitive radio networks (CRNs) enable efficient spectrum sharing but face security challenges.
• Wireless-powered CRNs (WPCRNs) integrate energy harvesting (EH) nodes, introducing potential eavesdropping risks.
• Untrusted EH nodes can compromise data confidentiality by decoding signals instead of harvesting energy.

Purpose of the Study:

• To maximize the average secrecy rate for secondary users (SUs) in WPCRNs.
• To ensure interference to primary users (PUs) remains below a specified threshold.
• To guarantee minimum energy harvesting (EH) requirements for all EH nodes.

Main Methods:

• Derivation of an analytical expression for optimal transmit power using dual decomposition.
• Development of a low-complexity, suboptimal transmit power control algorithm implemented iteratively.
• Analysis of system performance considering secrecy rate, interference, and energy harvesting constraints.

Main Results:

• The proposed suboptimal algorithm achieves high average secrecy rates.
• Performance significantly surpasses conventional distributed schemes, showing over 10% improvement in secrecy rate and outage probability.
• The algorithm offers a substantial reduction in computation time compared to optimal solutions.

Conclusions:

• The developed iterative power control algorithm effectively balances security and energy efficiency in WPCRNs.
• This approach provides a practical solution for enhancing secure communications in energy-constrained wireless networks.
• The findings demonstrate the feasibility of achieving high secrecy rates while respecting PU interference and EH requirements.