8192QAM Signal Transmission by an IM/DD System at W-Band Using Delta-Sigma Modulation

We present a low-cost intensity-modulated direct detection (IM/DD) system for the transmission of high-order QAM signals at millimeter-wave (MMW) band at 87 GHz. The system uses photon-assisted MMW generation techniques to transmit modulated signals and receive signals through low-cost envelope detection. Discrete multi-tone (DMT) signals up to 8192QAM are modulated into a one-bit quantized on/off keying (OOK) signal with delta-sigma modulation (DSM) to avoid envelope detector saturation effects and reduce nonlinear noise interference. Additionally, multi-level digital-to-analog converters (DACs) are not required. The 87 GHz W-band signal can transmit data at a baud rate of 12 G over a wireless propagation range of 1.2 m. The experimental results show that the bit error ratio (BER) of the 1024QAM signal can reach the hard decision forward error correction (HD-FEC) threshold, and the BER of the 8192QAM signal can reach the soft decision forward error correction (SD-FEC) threshold. To our knowledge, this is the first time that the DSM modulation format is used in the IM/DD W-band wireless transmission system.