Min-max BER Based Power Control for OFDM-Based Cognitive Cooperative Networks with Imperfect Spectrum Sensing

In this paper, a power control (PC) algorithm for multiuser Orthogonal Frequency Division Multiplexing (OFDM)-based cognitive cooperative networks under the imperfect spectrum sensing is studied to minimize total Bit Error Rate (BER) of secondary users (SUs) under the consideration of maximum transmit power budgets, signal-to-interference-and-noise ratio (SINR) constraints and interference requirements to guarantee quality of service (QoS) of primary user (PU). And a cooperative spectrum sensing (CSS) strategy is considered to optimize sensing performance. The worst-channel-state-information (worst-CSI) PC algorithm is introduced to limit the BER of SUs, which only needs to operate the algorithm in one link that CSI is worst, while the interference model is formulated under the consideration of spectrum sensing errors. In order to obtain optimal solution, the original min-max BER optimization problem is converted into a max-min SINR problem solved by Lagrange dual decomposition method. Simulation results demonstrate that the proposed scheme can achieve good BER performance and the protection for PU.