A new-type cognitive radio system based on spectrum sensing and statistical division multiplexing

Cognitive radio is a promising solution for the problem of inefficient and uneven spectrum utilization. In this paper, a new-type cognitive radio system based on spectrum sensing (SS) technology and statistical division multiplexing (SDM) theory is proposed. Our system contains two main parts, i.e., the spectrum sensing subsystem and the statistical separation module. And corresponding algorithms for each part are also presented. Two viewpoints are argued: one is that multiple secondary users (SUs) can access to the desired frequency bands licensed to the primary user (PU) simultaneously without local transmit power constraint; the other is that the number of SUs should satisfy the requirements of algorithm complexity. Hence, the proposed system allows multiple source signals to transmit together in the same frequency band over wireless channels, which can further enhance the system spectral efficiency. Besides, it needs nearly no prior knowledge except that statistical difference between source signals. Simulation results have supported the above viewpoints and validated the feasibility of the novel cognitive radio system as well.