Subcarrier and power allocation for OFDM-based cognitive radio networks

Orthogonal frequency division multiplexing (OFDM) is an attractive modulation candidate for cognitive radio networks. This paper focuses on the subcarrier and power allocation for OFDM-based cognitive radio network. Our objective is to maximize secondary user's transmission rate by adjusting its power resource under the constraint of primary user's tolerable interference limit. First, we proposed a power allocation scheme based on convex optimization theory. Then, in order to fairly allocate subcarrier and power resource among multiple secondary users, we proposed a joint subcarrier and power allocation scheme. Simulation results showed that these schemes can maximize the transmission rate and guarantee the fairness of multiple secondary users under the interference power constraint.