Active secondary user selection algorithm of simo opportunistic spatial orthogonalization in fading cognitive radio networks

The opportunistic spatial orthogonalization (OSO) scheme, proposed by Cong Shen and Michael P. Fitz, allows the existence of secondary users during the period in which the primary user is occupying all licensed bands. This paper introduces an active secondary user selection algorithm which mitigates the interference from the primary user transmitter to the secondary user receiver. In order to select the active secondary user, we adopt a fusion center concept, which is utilized for the cooperative spectrum sensing. A proposed algorithm guarantees the minimum average throughput of the primary user and overcomes the average sum throughput of a conventional OSO. We have numerically analyzed the average throughput under various constraints.