Joint user selection and quantized power control schemes for uplink cognitive MIMO systems

In this paper, we investigate interference-aware joint secondary user (SU) selection/scheduling and quantized power control (JSUS-QPC) schemes for the uplink communication in the cognitive MIMO system. The main objective of the JSUS-QPC is to maximize the sum-rate capacity of the cognitive MIMO uplink communication system under the constraint that the interference to the primary users (PU) is below a specified level. The computational complexity of finding an optimal JSUS-QPC scheme by exhaustive search grows exponentially with the number of users and power levels. In this paper, we present two low-complexity algorithms for JSUS-QPC in the cognitive MIMO system. We also examine the effect of different system parameters (e.g., interference threshold level, the number of primary users, the number of secondary users, the number of quantized power levels etc.) on the performance of the proposed algorithms. The proposed algorithms have low computational complexity, and their effectiveness is verified through simulation results.