Hybrid Grouped Transmission and Probabilistic Shaping for Mitigating High-SNR Nonlinearities in UV DCO-OFDM Communication System

This paper focuses on the critical challenge of peak-to-average power ratio (PAPR)-induced nonlinear distortions in LED-based ultraviolet (UV) communication systems employing direct current-biased optical orthogonal frequency division multiplexing (DCO-OFDM). While DCO-OFDM enhances spectral efficiency, its high PAPR deteriorates LED nonlinear clipping effects, severely degrading bit-error rate (BER) performance at high signal-to-noise ratios (SNR). We propose a hybrid grouped transmission and probabilistic shaping (H-GTAPS) to mitigate these distortions in UV communications. By partitioning subcarriers into multiple LED-driven groups and optimizing symbol probability distributions via Maxwell-Boltzmann shaping, our proposed H-GTAPS method suppresses PAPR while maintaining spectral utilization. Simulation results demonstrate a significant PAPR reduction and improved BER performance under UV-LED nonlinearity compared to conventional schemes in UV communications. This work offers a feasible pathway to reconcile high-order modulation demands with LED hardware constraints.