Performance Evaluation of Dual RIS-Assisted Received Space Shift Keying Modulation

TL;DR

This paper introduces a dual-RIS system that dynamically configures one RIS based on data bits to enhance indoor wireless communication, analyzing its capacity and reliability improvements over traditional static RIS setups.

Contribution

It proposes a novel dual-RIS architecture with bit-driven spatial modulation, including comprehensive system modeling and performance analysis for indoor wireless environments.

Findings

Enhanced capacity with dual-RIS configuration

Reduced outage probability through dynamic RIS control

Effective data-dependent signal steering demonstrated

Abstract

Reconfigurable intelligent surfaces (RISs) are gaining traction for their ability to reshape wireless environments with low energy consumption. However, prior studies primarily explore single-RIS deployments with static or semi-static reflection control. In this paper, we propose a novel dual-RIS-assisted architecture for smart indoor wireless signal routing, wherein the second RIS (RIS$_2$) is dynamically configured based on source data bits to steer signals toward specific receivers or indoor zones. The first RIS (RIS$_1$), positioned near a fed antenna or access point, passively reflects the incident signal. RIS$_2$, equipped with a lightweight controller, performs bit-driven spatial modulation to enable data-dependent direction selection at the physical layer. We develop a complete end-to-end system model, including multi-hop channel representation, RIS phase configuration mapping, and signal detection based on space shift keying (SSK). Performance analysis is evaluated in terms of achievable capacity and outage probability under varying inter-RIS distances and carrier frequencies.