The previously reported hybrid orthogonal frequency division multiplexing-digital filter multiple access (OFDM-DFMA) PONs offer promising solutions for seamlessly converging optical and mobile networks for 5G. However, the hybrid OFDM-DFMA PONs based on intensity-modulation and direct-detection (IMDD) convey double sideband (DSB) signals at different sub-wavelengths, this halves the spectral efficiency and signal transmission capacity. In this article, hybrid single sideband (SSB) OFDM-DFMA PONs are proposed and explored, for the first time, where multiple SSB OFDM channels produced without employing the Hilbert transform operation are multiplexed using orthogonal digital filtering in ONUs, and demultiplexed/demodulated by a single FFT operation in OLT without incorporating matching filters. It is shown that similar to the DSB PON, the proposed SSB PON has excellent robustness against digital filter characteristic variations and channel interferences. More importantly, it decreases peak-to-average power ratios (PAPRs) of digitally-filtered OFDM signals by >2 dB, thus leading to >2 dB reductions in optimum signal clipping ratio and >1 bit reductions in minimum required DAC/ADC resolution bits. For fixed spectral bandwidths, the SSB PON almost doubles the maximum upstream transmission capacity without considerably degrading its differential ONU optical launch power dynamic range compared to the DSB PON. While for fixed upstream signal transmission capacities, compared to the DSB PON, the SSB PON not only halves the overall signal transmission bandwidth, but also leads to >2.5 dB (>1.2 dB) improvements in power budget (differential optical launch power dynamic range for ONUs locating at high frequency regions).

中文翻译：

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混合 SSB OFDM 数字滤波器多址 PON


之前报道的混合正交频分复用-数字滤波器多址 (OFDM-DFMA) PON 为无缝融合 5G 光学和移动网络提供了有前景的解决方案。然而，基于强度调制和直接检测（IMDD）的混合OFDM-DFMA PON在不同子波长处传送双边带（DSB）信号，这使得频谱效率和信号传输容量减半。在本文中，首次提出并探索了混合单边带 (SSB) OFDM-DFMA PON，其中在 ONU 中使用正交数字滤波对不采用希尔伯特变换操作产生的多个 SSB OFDM 信道进行复用，并通过以下方法进行解复用/解调： OLT 中的单个 FFT 运算无需合并匹配滤波器。结果表明，与 DSB PON 类似，所提出的 SSB PON 对数字滤波器特性变化和信道干扰具有出色的鲁棒性。更重要的是，它将数字滤波 OFDM 信号的峰均功率比 (PAPR) 降低了 >2 dB，从而导致最佳信号限幅比降低 >2 dB，所需的最低 DAC/ADC 分辨率降低 >1 位位。对于固定光谱带宽，与 DSB PON 相比，SSB PON 的最大上行传输容量几乎翻倍，而不会显着降低其差分 ONU 光发射功率动态范围。而对于固定的上行信号传输能力，与DSB PON相比，SSB PON不仅使整体信号传输带宽减半，而且还导致功率预算（差分光发射）>2.5 dB（>1.2 dB）的改善位于高频区域的 ONU 的功率动态范围）。