A worst-case robust distributed power allocation scheme for OFDM-based cognitive radio networks

It is a complex task to allocate the secondary users´ power in OFDM-based cognitive radio networks which have many sub-carriers, especially when the channel uncertainty and coupled interference exist in cognitive networks. To address the issue, a worst-case robust distributed power allocation scheme is proposed for OFDM-based cognitive radio networks in this paper. Firstly, a robust power allocation model is constructed using worst-case approach with the uncertain channel state information. A non-cooperation game framework is introduced to optimize secondary users´ rate from their own profit individually with the primary user interference constraint. The variational inequality is employed to analyze the existence and uniqueness of the Nash equilibrium. The proposed scheme could optimize the power allocation under uncertain channel information and maximize secondary users´ rate. And the primary user interference temperature could also be satisfied even the channel in the worst case. The simulation is presented to valid its applicability and robust in a variety of scenes.