Power Allocation in NOMA-CR for 5G Enabled IoT Networks

 In the power domain, non-orthogonal multiple access (NOMA)supports multiple users on the same time-frequency resources, assigns dif-ferent transmission powers to different users, and differentiates users byuser channel gains. Multi-user signals are superimposed and transmitted inthe power domain at the transmitting end by actively implementing con-trollable interference information, and multi-user detection algorithms, suchas successive interference cancellation (SIC) is performed at the receivingend to demodulate the necessary user signals. In contrast to the orthogo-nal transmission method, the non-orthogonal method can achieve higherspectrum utilization. However, it will increase the receiver complexity. Withthe development of microelectronics technology, chip processing capabilitiescontinue to increase, laying the foundation for the practical applicationof non-orthogonal transmission technology. In NOMA, different users aredifferentiated by different power levels. Therefore, the power allocation hasa considerable impact on the NOMA system performance. To address thisissue, the idea of splitting power into two portions, intra-subbands and inter-subbands, is proposed in this study as a useful algorithm. Then, such optimiza-tion problems are solved using proportional fair scheduling and water-fillingalgorithms. Finally, the error propagation was modeled and analyzed for theresidual interference. The proposed technique effectively increased the systemthroughput and performance under various operating settings according tosimulation findings. A comparison is performed with existing algorithms forperformance evaluation