In PON-based mobile fronthauls, direct inter-ONU communications without passing end-user traffic to the OLT offer a promising solution for fulfilling the stringent latency and bandwidth requirements of 5G and beyond networks. In this paper, with slight modifications to the PON remote node, a concurrent inter-ONU and upstream communication technique is proposed and experimentally demonstrated in 101.6Gbit/s multipoint-to-point hybrid SSB OFDM digital filter multiple access (DFMA) IMDD PONs over 25km SSMFs. Multiple gapless inter-ONU and upstream SSB signals are aggregated by digital orthogonal filtering in each ONU transmitter. A single FFT operation is applied for demultiplex and demodulation in the OLT/ONU receivers. The results show that for both the inter-ONU and upstream transmissions, the optimum length of digital filters is 32, based on which the power penalties due to the fiber transmission and ONU channel interference are <1dB and <2dB, respectively. For the inter-ONU communications, adaptive RF spectral assignments can effectively mitigate the Rayleigh and Brillouin backscattering effects and the upstream channel fading effect, thus giving rise to >30% improvements in aggregated signal transmission capacity. In addition, detailed experimental investigations are also undertaken of the trade-off between differential ONU optical launch power dynamic range and aggregated signal transmission capacity. An approximately 1dB increase in ONU launch power dynamic range is achievable by reducing the aggregated signal transmission capacity by 5Gbit/s.

中文翻译：

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基于 IMDD 混合 SSB OFDM-DFMA PON 的下一代移动前传并发 ONU 间通信

在基于 PON 的移动前传中，无需将最终用户流量传递到 OLT 的直接 ONU 间通信为满足 5G 及更高网络的严格延迟和带宽要求提供了有前景的解决方案。在本文中，对 PON 远程节点稍作修改，提出了一种并发的 ONU 间和上行通信技术，并在 101.6Gbit/s 多点对点混合 SSB OFDM 数字滤波器多址 (DFMA) IMDD PON 上进行了实验演示25 公里 SSMF。多个无缝 ONU 间和上行 SSB 信号通过每个 ONU 发射机中的数字正交滤波聚合。在 OLT/ONU 接收器中应用单个 FFT 操作进行解复用和解调。结果表明，对于 ONU 间和上行传输，数字滤波器的最佳长度为 32，基于此，光纤传输和ONU信道干扰造成的功率损失分别<1dB和<2dB。对于ONU间通信，自适应RF频谱分配可以有效缓解瑞利和布里渊后向散射效应和上行信道衰落效应，从而使聚合信号传输容量提高30%以上。此外，还对差分ONU光发射功率动态范围和聚合信号传输容量之间的权衡进行了详细的实验研究。通过将聚合信号传输容量降低 5Gbit/s，可以实现 ONU 发射功率动态范围增加约 1dB。对于ONU间通信，自适应RF频谱分配可以有效缓解瑞利和布里渊后向散射效应和上行信道衰落效应，从而使聚合信号传输容量提高30%以上。此外，还对差分ONU光发射功率动态范围和聚合信号传输容量之间的权衡进行了详细的实验研究。通过将聚合信号传输容量降低 5Gbit/s，可以实现 ONU 发射功率动态范围增加约 1dB。对于ONU间通信，自适应RF频谱分配可以有效缓解瑞利和布里渊后向散射效应和上行信道衰落效应，从而使聚合信号传输容量提高30%以上。此外，还对差分ONU光发射功率动态范围和聚合信号传输容量之间的权衡进行了详细的实验研究。通过将聚合信号传输容量降低 5Gbit/s，可以实现 ONU 发射功率动态范围增加约 1dB。聚合信号传输容量提高 30%。此外，还对差分ONU光发射功率动态范围和聚合信号传输容量之间的权衡进行了详细的实验研究。通过将聚合信号传输容量降低 5Gbit/s，可以实现 ONU 发射功率动态范围增加约 1dB。聚合信号传输容量提高 30%。此外，还对差分ONU光发射功率动态范围和聚合信号传输容量之间的权衡进行了详细的实验研究。通过将聚合信号传输容量降低 5Gbit/s，可以实现 ONU 发射功率动态范围增加约 1dB。