Design and Analysis of NOMA With Adaptive Modulation and Power Under BLER Constraints

In this work, we derive closed-form expressions for the throughput of non-orthogonal multiple access (NOMA) and use the expressions to maximize the throughput. The design considers a packet-based transmission where the base station optimizes the modulation orders and power coefficients while satisfying the block error rate requirement for each user. The optimization problem is solved using integer and mixed-integer programming, where the computational complexity is reduced using an efficient stopping criterion, segment-line search, and quantized signal to noise ratios (SNRs). The analytical and simulation results show that selecting the appropriate power and modulation orders can improve the throughput by about 3 dB at high SNRs. The impact of the SNR quantization is evaluated, and the obtained results show that the proposed system can tolerate large quantization steps, which enables reducing the complexity of the optimization and adaptation processes.