Research on Power Allocation Algorithm in Non-orthogonal Multiple Access Systems

With the development of 5G technology, the power allocation problem in non-orthogonal multiple access technique (NOMA) becomes one of the key technologies. Due to the high complexity of the traditional optimal iterative water-filling algorithm and the fast iterative water-filling algorithm, a lower complexity algorithm is proposed in this paper. Firstly, the improved linear water-filling algorithm is used for power allocation in sub-carriers. Secondly, users on each sub-carrier use fractional power allocation algorithm to reallocate power. Finally, the simulation results show that the proposed algorithm approaches the linear water-filling algorithm in the transmission rate of the system, and complexity is lower.