The rapidly increasing data traffic in modern mobile communication systems necessitates the use of higher-frequency spectrum bands. This anticipated surge in mobile traffic in 5G networks has raised major concerns regarding power consumption. To address the energy-efficiency requirements of 5G—particularly its goals of low latency and reduced computational complexity—several multicarrier modulation schemes have been investigated as potential physical-layer solutions. However, most of these waveforms suffer from a high Peak-to-Average Power Ratio (PAPR), which limits power efficiency. To mitigate this challenge, various constant-envelope–based approaches have been explored. In this paper, we propose a hybrid modulation technique called Spatial Modulation Constant-Envelope OFDMA (SM-CE-OFDMA), which combines spatial modulation with constant-envelope OFDMA. The proposed scheme significantly enhances system performance under AWGN conditions and achieves a 3.01 dB reduction in PAPR. The system was modeled and simulated using MATLAB. Furthermore, a comparative analysis of the Bit Error Rate (BER) and Signal-to-Noise Ratio (SNR) performance for the different transmission modules is presented to demonstrate the effectiveness of the proposed method.