Date Added: May 2012
Power control plays a key role in realizing reliable and spectrum-efficient communications in a cognitive radio network. In this paper, the authors study secure power control schemes for cognitive radios via a robust Markov Decision Process (MDP) approach. They first use the Discrete Time Markov Chain (DTMC) model to characterize the Primary User's (PU) activities as well as the dynamics of the fading channel. The resulting power control problem can be optimally solved by a Dynamic Programming (DP) approach. The presence of malicious users, however, necessitates a cooperative spectrum sensing approach that requires extra signal processing and information exchange efforts to identify false spectrum sensing reports. Such a cooperative approach incurs considerable delay in spectrum sensing that may significantly deteriorate the performance of the DP strategy.