An Information Transmission Scheme for RIS-Aided Wireless Communication Network

This paper introduces a reconfigurable intelligent surface (RIS)-aided wireless communication network, where an RIS simultaneously transmits the information and reflects an impinging radio frequency signal. Moreover, the RIS explicitly embeds its information bits in the discrete phase shifts of reflecting elements, which are selected from the reflection phase modulation (RPM) constellation. Further, access point (AP) exploits the pulse amplitude modulation (PAM) constellation to convey its information bits. Both RIS and AP independently transmit their data to the receiver using RPM and PAM symbols. In addition, joint decoding of RPM and PAM constellations symbols is performed using a maximum likelihood (ML)-detector, and a tight upper bound of the average bit error rate (ABER) is presented. A unified analytical framework of the average pairwise error probability over double Rayleigh fading channels is derived, which is followed by the ABER expression. Furthermore, it is noticed from the numerical results that the proposed scheme attains high data rates with remarkably lower error rates in very low SNR regime.