Outage Probability Minimization under Both The Transmit and Interference Power Constraints for Fading Channels in Cognitive Radio Networks

In this paper, we consider a spectrum-sharing environment where a secondary user (SU) is allowed to access the spectrum allocated to a primary user (PU) on condition that the interference power received at the receiver of PU is below a predefined threshold. In particular, besides this interference power constraint defined to protect the PU, we also consider the power limit at the transmitter of the SU. Under such a setup, we derive the optimal power allocation strategies to achieve the minimum outage probability for fading channels and quantify the relationship between the power constraints and the outage probability. Besides, we also study the zero-outage capacity (also known as delay-limited capacity) under the same setup. Finally, computer simulations are conducted to verify our theoretical results.