An proportional fair resource allocation in OFDM-based cognitive radio networks under imperfect Channel-State information

In this paper, we investigate the subchannel assignment and power allocation algorithm for downlink OFDM-based cognitive network where the Channel-State Information(CSI) between the secondary system and the primary system is imperfect. We formulate an optimization problem under both the interference-power outage constraint and maximum transmit-power constraint to maximize the spectrum utility and provide proportional fairness to the SUs. Lagrangian duality method is used to solve the problem. Simulation results show that the proposed algorithm achieve good performance in terms of fairness and spectrum efficiency.