Research on Full-Space Spectrum-Sharing Strategy for Massive MIMO Cognitive Radio Systems

Large-scale antenna technology is a key technology for the fifth-generation mobile communication (5G) system to improve capacity and spectrum utilization; meanwhile, cognitive radio (CR) can vastly improve the utilization of unexploited spectrum resources. This paper employs three CR base stations to realize spectrum sharing in full space, where three CR base stations are placed at neighboring walls of a cell and distinguish CRs in the cell by their angular information. To reduce pilot contamination and overhead emerged during uplink and downlink training, this paper performs two dimensional discrete Fourier Transform to obtain the direction of arrivals and the angular spread of primary radios (PRs) and CRs. At last, this paper proposes a greedy CR scheduling algorithm for three CBS system. To testify three CBS system's efficiency and effectiveness, performs similar greedy CR scheduling algorithms on two CBS systems. The three CBS systems demonstrate remarkable superiorities by recognizing and scheduling more CRs in less scheduling time, especially when the number of CRs exceeds 100.