Full Duplex Millimeter Wave Radio over Fiber with 24 Gbps 4-QAM Downstream Signal in W Band (75-110 GHz)

  • Nauman Ashraf
  • Furqan Shaukat


We propose a millimeter-wave radio over fiber transmission system in the W-band (75–110 GHz) with quadrature amplitude modulation and wavelength reuse ability. Optical millimeter-wave carriers are generated at the central station by frequency quadrupling a 16.75GHz local oscillator using two LiNb Mach-Zehnder modulators. 24 Gbps of downlink data is single side band modulated with one of the tones generated by LiNb Mach-Zehnder modulators and sent over a 30 km long single mode fiber. At the base station, beating of tones occurs at a high speed photodetector and generates an 87GHz millimeter wave containing the downlink data. Another local oscillator millimeter wave at 67GHz is generated with the use of fiber Bragg reflectors. This millimeter wave is used to down convert the uplink data received wirelessly from the user station to 4 GHz. The down converted uplink data is double side band modulated with the second tone which was received from the base station and partially reflected by fiber Bragg reflector and sent to the central station, thus keeping the access units simple. The simulation analysis for 4 and 16 quadrature amplitude modulation shows that the full duplex model has good performance with bit error rate below forward error correction limits even after 30 km standard single mode fiber transmission at 24 Gbps without any inline dispersion compensation.