Non-orthogonal multiple access (NOMA) has been recognized as an attractive technique to address the increasing traffic demands for heterogeneous wireless networks. The conventional fast Fourier transform NOMA (FFT-NOMA) system causes inter-user-interference (IUI), and high peak to average power ratio (PAPR) because of the superposition of multiple users on the same frequency subchannel. To reduce the PAPR, IUI, and bit error rate (BER) in a FFT-NOMA system, the enhanced-NOMA (E-NOMA) scheme is proposed that consists of a new low-complexity modified version of the conventional selected mapping (CSLM) cascaded with the Walsh–Hadamard transform (WHT). Simulation results demonstrate that the proposed E-NOMA scheme outperforms the FFT-NOMA with reference to PAPR and BER about 4.3 dB and 9.5 dB, respectively. Furthermore, at least 56% computational complexity reduction is achieved compared to an SLM-based NOMA method.

非正交多路访问 (NOMA) 已被公认为是解决异构无线网络日益增长的流量需求的一种有吸引力的技术。传统的快速傅里叶变换NOMA（FFT-NOMA）系统由于多个用户在同一频率子信道上的叠加，导致用户间干扰（IUI）和高峰均功率比（PAPR）。为了降低 FFT-NOMA 系统中的 PAPR、IUI 和误码率 (BER)，提出了增强型 NOMA (E-NOMA) 方案，该方案由传统选择映射 (CSLM) 的新低复杂度修改版本组成。 ) 与 Walsh-Hadamard 变换 (WHT) 级联。仿真结果表明，所提出的 E-NOMA 方案在 PAPR 和 BER 方面优于 FFT-NOMA，分别约为 4.3 dB 和 9.5 dB。此外，