Interference Alignment Algorithm for Considering the Throughput of Cognitive Users in Cognitive MIMO Network

The cognitive multiple input multiple output( MIMO)network can utilize radio spectrum efficiently and satisfy the demand of high data rate. In order to decrease the interference during transmission,a new interference alignment( IA) algorithm based on cognitive MIMO networks is proposed in this paper. The algorithm is realized by designing two-level pre-coding, the first-level precoding aligns the interference generated by the cognitive users( CUs) to unused sub-channels of the primary user( PU),thereby eliminating the interference of CUs to PU; the second-level precoding is used to improve the throughput of CUs. Simulation shows that the proposed IA algorithm can eliminate the interference that the CUs produce on the PU and improve the throughput of CUs spontaneously.