Optimal Adaptive Bit Loading and Subcarrier Allocation Techniques for OFDM based Cognitive Radio Systems

Abstract—We propose an integer linear programming based adaptive bit loading and subcarrier allocation technique for a cognitive radio network. The proposed technique considers interference leakage to and from multiple primary users and sec-ondary users in order to optimise the throughput of the secondary network while keeping the interference to primary network below a specific value. The simulation framework explicitly considers baseband filter response of the primary network and its impact on the interference leakage to the secondary network. Index Terms—Cognitive radio, radio resource allocation, in-teger linear programming, OFDMA, bit allocation, branch and bound method. I