A Nonlinear Modulation and Demodulation Method Design Applied to RIS Communication System

To meet the demand of information modulation and demodulation in RIS communication system, this paper realizes a signal modulation and demodulation method that can realize 16QAM communication by manipulating the phase of electromagnetic signal in space only by RIS. This modulation and demodulation method relies on the RIS system that can continuously adjust the phase of the signal, which can control the RIS to modulate any information completely at the RF signal by voltage signal in the RIS segment, and achieve complete coarse synchronization, CFO correction, fine synchronization and accurate restoration of the sent 16QAM code element signal at the receiver side. This modulation and demodulation method is verified by experiments in USRP environment and can achieve transmission rate of 1Mbps with BER below 0.01%.