Indexed Multiple Access with Reconfigurable Intelligent Surfaces: The Reflection Tuning Potential

TL;DR

This paper surveys indexed modulation-enabled multiple access techniques, highlights their advantages over traditional methods, and introduces a novel RIS-indexed scheme that uses phase tuning for multi-user data embedding, demonstrating performance improvements.

Contribution

It provides a comprehensive survey of IM-based MA techniques, identifies limitations of existing schemes, and proposes a new RIS-indexed approach with dynamic phase tuning for enhanced multi-user communication.

Findings

Simulation confirms performance gains of RIMA scheme.

RIS deployment enhances multi-user data embedding.

Theoretical analysis shows advantages over non-indexed schemes.

Abstract

Indexed modulation (IM) is an evolving technique that has become popular due to its ability of parallel data communication over distinct combinations of transmission entities. In this article, we first provide a comprehensive survey of IM-enabled multiple access (MA) techniques, emphasizing the shortcomings of existing non-indexed MA schemes. Theoretical comparisons are presented to show how the notion of indexing eliminates the limitations of non-indexed solutions. We also discuss the benefits that the utilization of a reconfigurable intelligent surface (RIS) can offer when deployed as an indexing entity. In particular, we propose an RIS-indexed multiple access (RIMA) transmission scheme that utilizes dynamic phase tuning to embed multi-user information over a single carrier. The performance of the proposed RIMA is assessed in light of simulation results that confirm its performance gains. The article further includes a list of relevant open technical issues and research directions.