Zero-Energy RIS-Assisted Communications With Noise Modulation and Interference-Based Energy Harvesting

2025-06-03

AI Summary

To address the energy-supply bottleneck of passive reconfigurable intelligent surfaces (RISs) in carbon-neutral wireless communications, this paper proposes a zero-energy-consumption RIS-assisted noise-modulation communication paradigm. Methodologically, we design a dual-mode unit operation mechanism—where each RIS element simultaneously reflects incident signals and harvests interference energy for self-sustained operation; derive a closed-form solution for reflection coefficient allocation under stochastic energy constraints; and jointly optimize interference-driven energy harvesting, discrete-phase beamforming, and repetition coding. Theoretically, we obtain closed-form expressions for bit-error rate, mutual information, and energy efficiency under energy constraints. Simulation results demonstrate that, particularly in moderate-to-low interference regimes, the proposed scheme significantly improves energy-harvesting efficiency and communication success probability, outperforming conventional noise-modulation systems.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Search and Optimization: Sampling/Simulation-based Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation

Abstract

To advance towards carbon-neutrality and improve the limited {performance} of conventional passive wireless communications, in this paper, we investigate the integration of noise modulation with zero-energy reconfigurable intelligent surfaces (RISs). In particular, the RIS reconfigurable elements (REs) are divided into two groups: one for beamforming the desired signals in reflection mode and another for harvesting energy from interference signals in an absorption mode, providing the power required for RIS operation. Since the harvested energy is a random variable, a random number of REs can beamform the signals, while the remainder blindly reflects them. We present a closed-form solution and a search algorithm for REs allocation, jointly optimizing both the energy harvesting (EH) and communication performance. Considering the repetition coding technique and discrete phase shifts, we derive analytical expressions for the energy constrained success rate, bit error rate, optimal threshold, mutual information, {and energy efficiency}. Numerical and simulation results confirm the effectiveness of the algorithm and expressions, demonstrating the superiority of the proposed integration over conventional noise-modulation systems. It is shown that by properly allocating the REs, both the EH and communication performance can be improved in low to moderate interference scenarios, while the latter is restricted in the high-interference regime.

Problem

• Integrating noise modulation with zero-energy RIS for carbon-neutral communications
• Optimizing RE allocation for energy harvesting and beamforming performance
• Enhancing communication and EH in low-moderate interference scenarios

Innovation

• Zero-energy RIS with noise modulation
• Dual-mode REs for beamforming and energy harvesting
• Optimized RE allocation algorithm