The introduction of 5G enhanced mobile broadband (eMBB) services has brought unprecedented bit-rate demands to the optical transport infrastructure, which can hardly be supported through cost-effective digital fronthauling solutions. This opens up a whole new opportunity for bandwidth-efficient radio-over-fiber (RoF) analog fronthaul transmission, which avoids the well-known bandwidth multiplication issue associated with the digitization of radio signals. Using a low-cost directly-modulated laser (DML) with less than 3 GHz bandwidth and a standard PIN photodetector, we demonstrate the transmission of a carrier-aggregated 5G downlink signal over up to 25 km of single-mode fiber (SMF). Resorting to the use of intermediate-frequency-over-fiber (IFoF), we enable the transmission of 5G-compatible signals composed of up to 12 aggregated 400 MHz component carriers (CCs), resulting in a total radio bandwidth of 4.8 GHz, corresponding to >300 Gbps CPRI-equivalent downlink data-rate. 5G-compliant EVM performance across all CCs is achieved through the optimization of power and bit loading between component carriers, enabling an aggregated end user data-rate of 15.6 Gbps.

中文翻译：

---

通过比特和功率加载增强的多载波 5G 兼容基于 DML 的传输

5G增强型移动宽带（eMBB）业务的推出，给光传输基础设施带来了前所未有的比特率需求，而高性价比的数字前传解决方案几乎无法满足这一需求。这为带宽高效的光纤无线电 (RoF) 模拟前传传输开辟了全新的机会，避免了众所周知的与无线电信号数字化相关的带宽倍增问题。我们使用带宽低于 3 GHz 的低成本直接调制激光器 (DML) 和标准 PIN 光电探测器，演示了载波聚合 5G 下行链路信号在长达 25 公里的单模光纤 (SMF) 上的传输。诉诸于光纤中频（IFoF）的使用，我们能够传输由多达 12 个聚合的 400 MHz 分量载波 (CC) 组成的 5G 兼容信号，从而产生 4.8 GHz 的总无线电带宽，对应于 >300 Gbps CPRI 等效下行链路数据速率。通过优化分量载波之间的功率和比特负载，在所有 CC 上实现符合 5G 的 EVM 性能，从而实现 15.6 Gbps 的聚合最终用户数据速率。