Optimized User Pairing and Fairness-Driven Power Allocation for Enhanced Hybrid NOMA Downlink Performance

This study proposes an innovative pairing strategy for a Hybrid Non-Orthogonal Multiple Access (H-NOMA) system that incorporates fair power allocation algorithm to enhance downlink network performance and user satisfaction. The primary objectives are to reduce the complexity of Successive Interference Cancellation (SIC), improve spectral efficiency, and address power consumption issues for each user. By merging the benefits of traditional non-orthogonal schemes, such as Time Division Multiple Access (TDMA), with fair power distribution, this approach aims to optimize the performance of wireless communication systems. In the Hybrid NOMA-TDMA scenario, users are grouped based on their channel conditions, with power allocation adjusted accordingly. This allows for the simultaneous service of multiple users by dividing available time into sub-time slots and employing the power-domain NOMA technique. The proposed strategy maximizes the minimum per-user rate while adhering to system constraints. An optimization framework is developed to efficiently distribute transmission power and allocate time slots, utilizing both the power splitting factor algorithm and the proportional allocation algorithm. Extensive simulations assess the performance of downlink NOMA with fair power allocation, comparing the sum rates of TDMA, OFDMA, NOMA, and H-NOMA as the power splitting factor varies. The results indicate that the proposed approach significantly outperforms existing algorithms, achieving higher average sum rates for users. This research provides valuable insights into enhancing system efficiency and capacity, offering practical applications for future wireless communication systems.