Non-Orthogonal Uplink Services Through Co-Transport of D-RoF/A-RoF in Mobile Fronthaul

To efficiently support multiple services with diverse requirements in data capacity, latency, and connectivity in the fifth-generation (5G) communication system and beyond, various mobile fronthaul solutions, including digital and analog radio-over-fiber (RoF), will be considered. We propose a non-orthogonal multiplexing scheme for multiservice uplink transmissions in mobile fronthaul, where in-band analog RoF (A-RoF) signals can be transmitted with digital RoF (D-RoF) signals simultaneously, resulting in high spectrum resource utilization. The demultiplexing is fulfilled by exploiting different characteristics of the D-RoF and A-RoF signals in the time-domain and it can be implemented with analog signal processing, providing low processing complexity and processing delay. The proposed scheme is experimentally demonstrated to achieve the joint transmission of the D-RoF and A-RoF signals over a shared mobile fronthaul through 20-km standard single mode fiber (SSMF). Experimental results show that in-band A-RoF signals from 2-10 GHz can be co-transmitted with D-RoF 10 GBaud NRZ-OOK signals, with the signal-to-interference-plus-noise ratio (SINR) enhanced by the demultiplexing module. Both received D-RoF and A-RoF signals can achieve bit error ratio (BER) lower than the 7% hard-decision forward-error correction (FEC) threshold.