## 5 Experimental Demonstration of the Proposed Hybrid Transport Implementation
This infrastructure included, among other features, an EPC and a small cell. These two network units were interconnected along the node via 1 Gbps SFP transceivers emitting at \(\lambda_{3}\). Finally, the MNO's equipment was also used for the delivery of services through A-IFoF waveforms enrolled at \(\lambda\)4 transmitted over a converged FiWi link. In this case, the implemented FPGA-based A-IFoF transceiver reported in [44] served as a bridge for the transmission of the 1 Gbps SFP traffic, modulated by a 10 GHz EML that was emitting at \(\lambda\)4. The WSS-based optical node, described above, exhibited total insertion losses of 11 dB (4.5 dB coming from the AWG and 6.5 dB from the 1 \(\times\) 4 WSS), for this reason an EDFA was used in order to mitigate the optical loss. Figure 9 comprises the experimental results regarding the performance of the abovementioned different optical node routing RoF transport lanes. Figure 9 shows the constellations and corresponding EVM measurements after the switching of \(\lambda_{1}\) (SCM A-IFoF stream) between two output ports of the optical node. The EVM difference of 0.8% that was observed in the optical domain only (without the radio boards) can be attributed to the use of the different photoreceivers in the two links. Figure 9 illustrates two different transmission scenarios of a \(\lambda_{1}\) optical stream, carrying single-band QPSK signals. In the first case, only \(\lambda_{1}\) is propagated through the optical node, while in the second one, four optical streams are propagated through the node. In the WDM transmission, small EVM differentiations of up to 1.1% were observed, associated with the gain competition on the used EDFA due to the different power levels of the incoming signals. Figure 9 presents the successful evaluation of the concurrent transmission of four optical streams through the node. The wavelength \(\lambda_{1}\) was modulated with 3-band QPSK signals of 500 MHz, corresponding to 1.5 GHz analog aggregated radio traffic, and exhibited values well-bellow the 3 GPP threshold of 17.5% EVM for the successful demodulation  
Figure 9: (**a**) The SDN interface script for the WSS control, (**b**) Constellation diagrams corresponding to switching between port 2 and port 3 of WSS, (**c**) Performance evaluation of \(\lambda\)1 after single and WDM transmission, (**d**) Evaluation of successful concurrent \(\lambda\)A transmission. of the QPSK modulation after the IFoF-V-band transmission per [PERSON] et al. [40]. The wavelength \(\lambda_{2}\) was carrying 10 GHz on-off keying (OOK) signals that were emulating 10G D-RoF traffic and the measured Q-factor of 16.8 dB indicated error-free transmission (Bit-error-rate < \(10^{-9}\)) [37]. The CPRI traffic that was transmitted over \(\lambda_{3}\) was validated with the use of a MUE performing Iperf measurements, exhibiting up to 180 Mbps of stable connectivity. Moreover, 4K online video streaming, uninterrupted live IP-video teleconferences and web browsing were successfully demonstrated over \(\lambda_{4}\) where the A-IFoF-mmWave link was integrated by using the FPGA based A-IFoF platform in [44].