Multiuser OFDM resource allocation algorithm for cognitive radio

Based on the multiuser orthogonal frequency division multiplexing (MU-OFDM) technique and the characteristics of cognitive radio, a novel multiuser resource allocation algorithm is proposed. In this algorithm, the secondary users choose their subcarriers and powers to achieve their QOS requirements based on the knowledge of the channel detections. The maximal channel capability is achieved accordingly. A schedule parameter is introduced to fit the need of fairness between secondary users. Meanwhile a decline parameter and the terminal types are also considered during the subcarrier and power allocation, and the interference to the primary users is avoided. The algorithm is based on the two step method. As a result, calculations are reduced and the real time requirements are achieved. Simulation results indicate that our method can achieve about 40% performance improvement compared with FDMA in channel capability.