Converged RoF-based mobile fronthaul and passive optical network with NOMA-CAP modulation format

The current constant growth in mobile networks’ traffic demands, owing to the popularization of cloud and streaming services on personal devices, requires architectural changes to fulfill all the new 5G mobile network requirements and specifications. Cloud access radio network (C-RAN) architecture in combination with the massive deployment of small cell antenna sites has recently been proposed as a promising solution, though demanding, for high-capacity mobile fronthaul links. An efficient way to perform that connectivity is to make use of the deployed passive optical networks (PONs) where wireless and wired services may be converged for distribution purposes. Non-orthogonal multiple access (NOMA) combined with multi-band carrierless amplitude phase modulation (NOMA-CAP) has recently been proposed as a promising 5G and beyond modulation format candidate to increase the capacity and flexibility of future mobile networks. In this paper, for the first time we demonstrate the convergence of a NOMA-CAP wireless waveform with a single-carrier wired signal in a PON scenario using radio-over-fiber (RoF) technology. Specifically, fifteen NOMA-CAP bands with two power levels—hence doubling the capacity—transmit 15 Gb/s multiplexed with a digital 10 Gb/s fourlevel pulse amplitude modulation (PAM-4) signal for downlink application. The results show that the crosstalk interference can be minimized by controlling the amplitude relation between the NOMA-CAP and PAM-4 signals to maximize the wireless transmission bandwidth. Moreover, successful transmission over 25 km of standard single-mode fiber is also demonstrated with negligible transmission penalty.