Interference alignment and cancellation based concurrent transmission and scheduling scheme for multiuser CR-MIMO system

In this paper, an Interference Alignment and Cancellation (IAC) based transmission and scheduling scheme is proposed for an infrastructured Cognitive Radio (CR) Multiple-Input Multiple-Output (MIMO) system with multiple secondary users. With the cooperation of Primary Base Station (PBS) and Secondary Base Station (SBS), a signal processing procedure is designed to guarantee the priority of the primary transmission. As a reward for offering help to the PBS, the SBS is granted communication opportunity. The transmission difference of various spatial channels is exploited in Secondary User (SU) scheduling. With the proposed scheme, interference-free concurrent transmission of both PBS and SBS is implemented. Spatial channel resources can be effectively utilised compared with a traditional Interference Alignment (IA) based strategy. Simulation results show that the achievable data for primary transmission is enhanced by cooperative signal processing at the SBS. With respect to the SBS, its data rate grows with an increasing number of SUs by exploiting the multiuser diversity gain.