Optimizing direct-modulated laser LiFi systems for hospital environments through simulation-driven analysis of BER, SNR, and Q-factor performance

<ns3:p> Background Modern hospital environments require wireless communication systems that ensure electromagnetic interference (EMI) compliance, privacy, and high throughput for mission-critical applications, such as telemetry, medical imaging, and Electronic Health Record (EHR) synchronization. Traditional RF-based wireless systems are susceptible to EMI, limited spectrum availability, and security issues. Direct-Modulated Laser (DML)-based Light Fidelity (LiFi) offers a promising alternative by leveraging the visible spectrum for high-speed, interference-free communication. Methods The optimized configuration achieves BER ≈ 1.6 × 10 <ns3:sup>-79</ns3:sup> , SNR ≈ 74.94 dB, and Q ≈ 18.84 at 25 m, surpassing hospital reliability thresholds (BER &lt; 10 <ns3:sup>-9</ns3:sup> ; Q &gt; 6). Launch powers ≥ +5 dBm are required beyond ~15 m, modulation indices of 0.8–1.0 yield higher Q across distances, narrow beam divergences (1–2 mrad) maintain stronger SNR, and receiver apertures of 4–6 mm provide a balance between light collection and noise. Results The optimized configuration achieves BER ˜ 1.6 × 10?7?, SNR ˜ 74.94 dB, and Q ˜ 18.84 at 25 m, surpassing hospital reliability thresholds (BER &lt; 10??; Q &gt; 6). Launch powers = +5 dBm are required beyond ~15 m, modulation indices of 0.8–1.0 yield higher Q across distances, narrow beam divergences (1–2 mrad) maintain stronger SNR, and receiver apertures of 4–6 mm provide a balance between light collection and noise. Conclusions This work presents the first hospital-specific four-parameter DML-LiFi optimization framework, offering practical deployment rules for EMI-safe, high-throughput communication. The results establish DML-LiFi as a secure, scalable alternative to RF and LED-based systems, providing a foundation for next-generation hospital wireless infrastructure. </ns3:p>