Xu Yicheng, Zhu Yixiao, Fu Mengfan, Hu Weisheng, Zhuge Qunbi
Opt Lett. 2024 Sep 1;49(17):4803-4806. doi: 10.1364/OL.534747.
Analog radio-over-fiber (A-RoF) solutions for mobile fronthaul are regaining wide attention due to their high spectral efficiency and low complexity. However, the performance of A-RoF is usually limited by the fiber link fidelity. In this Letter, we propose and experimentally demonstrate an optical continuous pulse position modulation-based analog radio-over-fiber (OCPPM-RoF) scheme, in which the amplitudes of wireless waveforms are mapped to the time-domain positions of optical pulses to decouple the additive noise. The de-modulation of OCPPM-RoF signals is performed by a frequency-domain continuous position estimation (FD-CPE) algorithm including cross-power spectrum calculation and weighted least square for accurate delay estimation. In the experiment, by adopting appropriate pulse width factors, the recovered signal-to-noise ratio (SNR) can be flexibly adjusted within a wide range from 31.8 to 54.0 dB, supporting the transmission of various formats from 256-QAM to 65536-QAM. The results indicate that OCPPM-RoF can be a promising candidate for future fronthaul.
用于移动前传的模拟光纤无线电（A-RoF）解决方案因其高光谱效率和低复杂性而重新受到广泛关注。然而，A-RoF的性能通常受光纤链路保真度的限制。在本信函中，我们提出并通过实验演示了一种基于光连续脉冲位置调制的模拟光纤无线电（OCPPM-RoF）方案，其中无线波形的幅度被映射到光脉冲的时域位置，以解耦加性噪声。OCPPM-RoF信号的解调由频域连续位置估计（FD-CPE）算法执行，该算法包括交叉功率谱计算和加权最小二乘法以进行精确的延迟估计。在实验中，通过采用适当的脉冲宽度因子，恢复的信噪比（SNR）可以在31.8至54.0 dB的宽范围内灵活调整，支持从256-QAM到65536-QAM的各种格式的传输。结果表明，OCPPM-RoF可能是未来前传的一个有前途的候选方案。
