Nullspace-Based Secondary Joint Transceiver Scheme for Cognitive Radio MIMO Networks Using Second-Order Statistics

In this paper, we propose a practical nullspace-based secondary joint transceiver scheme for the coexistence of a secondary system and a primary system in cognitive radio MIMO (CR-MIMO) networks using second-order statistics. First, we propose a secondary transmission frame structure, and briefly describe the periodical nullspace sensing procedure for both the secondary transmitter (ST) and secondary receiver (SR). Then, we formulate nullspace-based secondary joint transceiver scheme by utilizing the nullspace at the ST as the secondary transmit precoding and the nullspace at the SR as the secondary receive beamforming from both theoretical and practical perspective. Furthermore, we focus on analyzing the effect of nullspace estimation errors on the performance of the primary system and the secondary system. Finally, simulations are presented to demonstrate the effectiveness of the proposed secondary joint transceiver scheme along with the theoretical analysis.