Joint Transmit Antenna Selection and User Selection in Cognitive Radio MIMO Systems

Using multiple antennas in coexisting radio systems can cancel or control the co-channel interference and hence improves the overall spectrum efficiency. However, the hardware complexity and costs limit the usage of multiple-antenna technology. Antenna selection may reduce such costs while partly remaining the advantage of the multiple-antenna technology. In this paper, a fixed power cognitive radio system model jointly combined with antenna selection and users selection is set up. And the mathematical closed-form expressions of the channel capacity and bit error rate (BER) are obtained through mathematical derivation. Simulation verifies the correctness of theoretical results and shows that the system exists an optimal transmit power which optimizes the system performance. Furthermore, the influences of users number and antennas number on the system performance have been studied.