Spectrum Allocation Algorithms for Uplink Sub-carriers in OFDMA-Based Cognitive Radio Networks

In cognitive radio (CR) networks, a secondary CR network borrows spectrum bands from primary networks for the purpose of improving spectrum efficiency. In this paper, we present a model in which a secondary network uses uplink sub-carriers by borrowing from a primary network in OFDM-based systems. We show optimization formulation and propose allocation algorithms for the model. Performance of proposed algorithms is evaluated by simulations. We can conclude that our CR network can be used to improve the utilization of precious bandwidth resource.