Carrier Sensing with Self-Cancelation of Inter-Carrier Emission in Cognitive OFDMA System

A novel carrier sensing method with self-cancelation of the inter-carrier emission inevitably existent in OFDMA-based coexisting systems is proposed. Different from the conventional energy-based carrier detector, which directly compares the carrier energy with some predefined thresholds without considering such inter-carrier emissions, our proposed method can remove them before making decision, thus significantly reduces the false-alarm probability and provides more access opportunities. Firstly, the detection model considering the inter-carrier emission is presented, and then the distribution of inter-carrier energy emission is investigated. Secondly, the energy emission of the detected adjacent carriers got by conservative pre-decision are gradually removed from the carrier to be detected. Finally, the performance of the proposed method is evaluated in terms of detection probability and false-alarm probability.