RIS-aided Media Based Modulation

Reconfigurable intelligent surface (RIS) technology and media based modulation (MBM) are promising physical layer techniques in wireless communication. While RIS uses electronically tunable surfaces in the far field of the transmit antenna(s) for the purpose of beamforming towards the receiver of interest, MBM uses such surfaces in the near field for the purpose of modulation. Both RIS and MBM offer improved communication performance at low radio-frequency (RF) hardware complexity. In this paper, we investigate MBM aided by RIS and show interesting performance results. We develop the system model for an RIS-aided MBM (RIS-MBM) system and analyse its bit error performance through analysis and simulation. For this system, we propose two schemes for optimizing the phases at the RIS, one maximizing the Frobenius norm of the channel and the other maximizing a bound on the achievable rate. We also compare the performance of RIS-aided MBM with that of RIS-aided generalized spatial modulation (RIS-GSM). Our results show that i) the performance of MBM improves with the use of RIS, ii) RIS phase optimization using rate maximization is better compared to that using Frobenius norm maximization, and iii) for a given rate, RIS-aided MBM achieves better performance compared to RIS-aided GSM.