Performance Optimization of Energy-Harvesting Underlay Cognitive Radio Networks Using Reinforcement Learning
In energy-constrained cognitive radio networks, secondary users (SUs) must coexist with primary users (PUs) while optimizing performance under stringent energy limitations. Method: This paper proposes a dynamic joint energy harvesting and data transmission decision framework. It innovatively treats PU communication signals—not as interference but as exploitable radio-frequency (RF) energy—and designs a dual-source adaptive energy harvesting mechanism. Integrating time-switching protocols with a deep Q-network (DQN), the framework jointly optimizes spectrum sensing, transceiver mode switching, and transmit power allocation. Contribution/Results: The proposed method significantly improves the SU’s average data rate, exhibits stable convergence, and consistently outperforms conventional benchmark strategies across diverse channel conditions and energy constraints. It establishes a novel paradigm for green, self-sustaining cognitive access by enabling SUs to autonomously harvest ambient RF energy from PU transmissions.