A hybrid bidirectional orthogonal frequency division multiplexing–millimeter wave over fiber (OFDM-MMWOF) transport system based on mixed quadrature amplitude modulation (QAM) format using dual-mode colorless laser diode and reflective semiconductor optical amplifier for next-generation 5G based networks is proposed and experimentally demonstrated. Here, an orthogonal quadruple frequency MMW is generated via optical heterodyne scheme. In case of downlink transmission, 10 Gbps baseband signal is transmitted over 80-km single-mode fiber (SMF) plus 500-m free space optical (FSO) distance and for the uplink, 5 Gbps baseband signal is transmitted over 80-km SMF plus 100-m FSO distance. For wireless transmission, 12.5 Gbps/60 GHz downlink MMW signal is generated and transmitted over 80-km SMF as well as 100-m wireless distance. 6.5 Gbps/30 GHz uplink MMW signal is communicated over 80-km SMF plus 50-m wireless distance. OFDM scheme with mixed QAM modulation technique enhances our spectral efficiency and simultaneously reduces inter symbol interference, inter-carrier interference, dispersion, etc. for long reach communication. The feasibility and reliability of our system is established by achieving low bit error rate (${10}^{-3}$), good error vector magnitude (<10.5% for 32 QAM and < 12.5% for 16 QAM), appropriate signal to noise ratio, and clear constellation diagram.

针对下一代基于5G的网络，提出了一种基于混合正交幅度调制（QAM）格式的双向双向正交频分复用-光纤毫米波混合传输系统，该系统采用双模无色激光二极管和反射型半导体光放大器。并通过实验证明。在此，经由光学外差方案产生正交的四倍频率MMW。如果是下行链路传输，则在80公里的单模光纤（SMF）上加上10米的500米自由空间光（FSO）距离传输10 Gbps的基带信号，而对于上行链路，则在80公里的SMF上传输5 Gbps的基带信号。再加上100米的FSO距离。对于无线传输，会生成12.5 Gbps / 60 GHz下行链路MMW信号，并在80公里SMF以及100米无线距离上进行传输。六 5 Gbps / 30 GHz上行MMW信号通过80公里SMF和50米无线距离进行通信。带有混合QAM调制技术的OFDM方案提高了频谱效率，同时减少了长距离通信的符号间干扰，载波间干扰，色散等。我们系统的可行性和可靠性是通过实现低误码率来建立的（${10}^{--3}$），良好的误差矢量幅度（对于32 QAM为<10.5％，对于16 QAM为<12.5％），适当的信噪比和清晰的星座图。