Optimal resource allocation based on interference alignment for OFDM and FBMC MIMO cognitive radio systems

In this paper, we present a radio resource allocation algorithm based on interference alignment (IA) for orthogonal frequency division multiplexing (OFDM) and filter bank multicarrier (FBMC) based MIMO cognitive radio (CR) systems. The algorithm provides the opportunity for all secondary users to share the available subcarriers simultaneously using IA technique. Besides, it allocates the power budget of each secondary user over the subcarriers in order to maximize the sum-rate of the system without inducing excessive interference to primary users. Simulations show that CR systems based on IA achieves a significant sum-rate increase compared to CR systems based on frequency division multiple access (FDMA). Moreover, IA based CR using FBMC physical layer achieves considerable throughput improvement compared to OFDM physical layer.