Frequency scheduling based interference alignment for cognitive radio networks

As a promising interference management technique, interference alignment (IA) has many applications, such as in cognitive radio (CR) networks. In CR networks, due to the coexistence of the secondary users (SUs) and the primary users (PUs), the signal-to-interference-plus-noise-ratio (SINR) at the PUs may decrease dramatically, leading to degraded performance of the PUs. In this paper, a novel IA algorithm based on frequency scheduling is proposed to guarantee the performance of PUs while sharing the spectrum with the SUs. In the algorithm, we divide SUs into multiple clusters, each of which forms an individual IA-CR network while guaranteeing the performance of the PUs. Thus a double-win game is established such that the PUs achieve performance gain with the aid of SUs while the SUs obtain more spectral opportunities. Simulation results are presented to verify the effectiveness of the proposed IA algorithm and its suitability for spectrum sharing in CR networks.