A Novel RIS-Assisted Modulation Scheme

TL;DR

This paper introduces a RIS-assisted modulation scheme that enhances spectrum efficiency by creating a virtual constellation diagram for multi-user uplink communication, with analytical performance evaluation.

Contribution

It proposes a novel RIS-based modulation method that transmits additional user data via virtual constellation diagrams, extending beyond traditional phase optimization techniques.

Findings

Derived a tight approximation for the CDF of received SNR.

Provided analytical expressions for average bit error rate of two users.

Demonstrated the trade-off between user performances based on RIS phase shifts.

Abstract

In this work, in order to achieve higher spectrum efficiency, we propose a reconfigurable intelligent surface (RIS)-assisted multi-user communication uplink system. Different from previous work in which the RIS only optimizes the phase of the incident users's signal, we propose the use of the RIS to create a virtual constellation diagram to transmit the data of an additional user signal. We focus on the two-user case and develop a tight approximation for the cumulative distribution function (CDF) of the received signal-to-noise ratio of both users. Then, based on the proposed statistical distribution, we derive the analytical expressions of the average bit error rate of the considered two users. The paper shows the trade off between the performance of the two users against each other as a function of the proposed phase shift at the RIS.