Heterogeneous MMW/VLC Access Networks Based on Convergent Photonic Fronthaul Links

This work experimentally demonstrates the convergence of visible light communications (VLC) and millimeter wave (mmW) wireless access technologies by using a unified optical fronthaul link that provides simultaneous signals to be transmitted over light emitting diode (LED) and seamless antennas-based links, respectively. Frequency multiplication is provided in the fiber link by using a carrier suppressed Mach-Zehnder modulator (CS-MZM) that offers a high-quality signal generation at both baseband (BB) and mmW frequencies. Moreover, this flexible and efficient photonic signal generation approach uses a directly modulated laser (DML) to take advantage of the relative gain given by the combination of the DML chirp and the fiber dispersion in the mmW band. Experimental trials of simultaneous VLC and mmW access have been done over distances up to 2.5 and 4 m, respectively; with maximum throughputs of around 70.3 and 393.1 Mbps for signal bandwidths of 30 and 100 MHz, respectively. Moreover, the effective transmission of different M-QAM OFDM modulation formats validates the approach as a promising enabler for future convergent heterogeneous 6G networks.