Power Allocation in OFDM-Based Cognitive Radio Systems
Peng Wang, Ming Zhao, Limin Xiao, Shidong Zhou, Jing Wang · 2007
In this paper, we investigate the optimal power allocation strategy that aims at maximizing the capacity in OFDM- based cognitive radio systems. We show that the traditional water-filling algorithm applied in general OFDM systems needs to be modified due to the per subchannel power constraints in such systems. An iterative partitioned water-filling algorithm is proposed and proved to be optimal based on the convex optimization theory.