Generation of 16-QAM-OFDM Signals Using Selected Mapping Method and Its Application in Optical Millimeter-Wave Access System

A simplified full-duplex 60-GHz optical millimeter-wave access system is proposed and experimentally demonstrated with a 16-QAM-OFDM downlink generated by selected mapping (SLM). The system receiver is realized with optical heterodyne detection and electrical self-mixing down-conversion. In the experiment, 5-Gb/s 16-QAM-OFDM signals are transmitted over 42-km SMF-28 and a 0.4-m wireless channel. The experimental results show that SLM can effectively reduce the peak-to-average power ratio and improve the receiver sensitivity. In addition, the proposed self-mixing down-conversion can simplify the transmitter and receiver configuration, since it eliminates the need for high-frequency microwave source at the central station and local oscillator at the base station.