Low Distortion Resource Allocation in NOMA based Cognitive Radio Networks

Abstract

To meet the demands of future generation wireless communications, Non-Orthogonal Multiple Access (NOMA) and Cognitive Radio (CR) are emerging technologies. In exchange of data over the wireless channels in these communications, interference is one of the major constraints in offering optimal service. The optimum utilization of resources depends on the accuracy of sensing, appropriate threshold selection, and proper resource allocation. In CR-NOMA cooperative relaying with fixed threshold was proposed for spectrum sharing in the existing works. The value of threshold plays a key role in decision making and a fixed value of the threshold is not an optimal solution for the dynamic channel environment. In addition to that maximum rate is allocated when the system meets interference, power, and rate constraints. But the accuracy of data reception was not considered. The loss of information in such a system has a greater impact on the overall performance of the system. To optimize the resource allocation in CR-NOMA with cooperative relaying, Quality Assured Resource Allocation (QARA) is proposed in this paper, where signal scaling, shaping, and probability of detection parameters are considered for defining the dynamic threshold and QoS monitoring is performed to assure accurate data communication. Here the bit error rate is calculated and the distortion is minimized by using the Lagrange Optimization method, which results in improved throughput. Simulation results indicate that the proposed system QARA outperforms the existing approaches.