Modulação Gaussiana versus PCS-64-QAM em CV-QKD: Demanda por Bits Aleatórios e Desempenho em SKR

• Caroline S. M. Alves EMBRAPII CIMATEC / UFBA https://orcid.org/0009-0006-0806-1045
• Nelson A. F. Neto EMBRAPII CIMATEC https://orcid.org/0000-0003-2278-1082
• Paulo C. M. A. Farias UFBA https://orcid.org/0000-0002-8423-4933
• Wagner L. A. de Oliveira UFBA https://orcid.org/0000-0003-1784-2661

DOI: https://doi.org/10.5753/wqunets.2026.22995

Resumo

Este trabalho investiga o impacto do esquema de modulação na demanda por aleatoriedade do QRNG e no desempenho de SKR em sistemas CV-QKD com detecção heteródina. A modulação gaussiana, implementada via transformada de Box–Muller, requer precisão de L ≈ 17 bits por quadratura para atingir o regime gaussiano, resultando em consumo de aproximadamente 34 bits por símbolo complexo. Em contraste, a modulação discreta com PCS, baseada em CCDM com blocos de N ≈ 10⁴, permite aproximar distribuições gaussianas com menor custo. Os resultados mostram que a PCS 64-QAM alcança desempenho próximo à modulação gaussiana, com alcance superior a 300 km e consumo de aproximadamente 4,9 bits/símbolo.

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