Abstract
Achieving good throughput and reducing interference to primary users (PUs) are key objectives for secondary users in a cognitive radio (CR) network. This paper proposes a centralized subcarrier allocation scheme with associated power allocation mechanism for underlay multi-user orthogonal frequency division multiplexing (MU-OFDM) taking into consideration the interference and rate loss that the PU can tolerate. The main target of the proposed scheme is to efficiently distribute the available subcarriers among cognitive users to maximize the cognitive network throughput while preserving the QoS for the PUs. The proposed algorithm achieves a significantly higher CR network throughput than that of the conventional interference power constraint IPC based schemes and the achieved throughput significantly increases as the number of CR users increases. Simulation results show that the proposed algorithm achieves a good performance in terms of fairness and spectrum efficiency.