Joint transmit power and sensing duration optimization for MIMO cognitive radios

We consider the problem of throughput maximization for MIMO cognitive radios, jointly with respect to the sensing duration and the secondary user transmit power, under imperfect null space sensing. The average interference to the primary receiver, due to imperfect null space sensing is derived. Next, the formulated non-convex throughput maximization problem is solved based on geometrical insights. Under the assumption of a large number of secondary transmit antennas and low SNR conditions, analytical closed-form approximations for the secondary user transmit power and the sensing duration are also obtained. Extensive simulation results are provided to demonstrate the efficacy of the proposed approach.