# Design and Performance Analysis of an RIS-Empowered RM-DCSK System for Wireless Powered Communication

## TL;DR

This paper introduces a new wireless communication system using reconfigurable intelligent surfaces and a modified chaos-based signaling method to improve performance and efficiency.

## Contribution

The novel system combines RIS and RM-DCSK to enhance spectral efficiency and reduce receiver complexity in wireless powered communication.

## Key findings

- The proposed system achieves better bit error rate performance compared to existing RIS-aided and bufferless systems.
- Using RIS improves the propagation environment and reduces path loss effects in wireless powered communication.
- A threshold-based transmission policy enables sustainable uplink transmission with energy harvesting.

## Abstract

This paper proposed a reconfigurable intelligent surface (RIS)-empowered reference-modulated differential chaos shift keying (RM-DCSK) wireless powered communication (WPC) system. As a noncoherent chaotic communication scheme, the proposed system exploits the reference reuse property of RM-DCSK, where the reference signal simultaneously carries data information, thereby improving spectral efficiency while maintaining noncoherent and channel-estimation-free reception with low receiver circuit complexity. Furthermore, RIS is utilized to reconfigure the propagation environment and mitigate the path loss effect of WPC links. At the user equipment (UE), a harvest–store–use (HSU) energy harvesting and finite-buffer model is developed, and a threshold-based on/off transmission policy is adopted to enable sustainable uplink transmission. To quantify the gain of energy buffering and management, a bufferless baseline system is further established. Closed-form bit error rate (BER) expressions are obtained under multi-path Rayleigh fading channels for both the proposed RIS-RM-DCSK-WPC system and bufferless baseline system. Finally, simulation results validate the analysis and demonstrate that the proposed system achieves superior BER performance compared with representative benchmarks, including existing RIS-aided DCSK-WPC, RM-DCSK-WPC, and bufferless RIS-RM-DCSK-WPC systems.