Space Shift Keying With Reconfigurable Intelligent Surfaces: Phase Configuration Designs and Performance Analysis

Qiang Li,Shuai Wang,George C Alexandropoulos,Yik-Chung Wu,Miaowen Wen

doi:10.1109/ojcoms.2021.3057118

Abstract

Reconfigurable intelligent surface (RIS)-assisted transmission and space shift keying (SSK) appear as promising candidates for future energy-efficient wireless systems. In this article, two RIS-based SSK schemes are proposed to efficiently improve the error and throughput performance of conventional SSK systems, respectively. The first one, termed RIS-SSK with passive beamforming (RIS-SSK-PB), employs an RIS for beamforming and targets the maximization of the minimum squared Euclidean distance between any two decision points. The second one, termed RIS-SSK with Alamouti space-time block coding (RIS-SSK-ASTBC), employs an RIS for ASTBC and enables the RIS to transmit its own Alamouti-coded information while reflecting the incident SSK signals to the destination. A low-complexity beamformer and an efficient maximum-likelihood (ML) detector are designed for RIS-SSK-PB and RIS-SSK-ASTBC, respectively. Approximate expressions for the average bit error probabilities of the source and/or the RIS are derived in closed-form assuming ML detection. Extensive computer simulations are conducted to verify the performance analysis. Results show that RIS-SSK-PB significantly outperforms the existing RIS-free and RIS-based SSK schemes, and RIS-SSK-ASTBC enables highly reliable transmission with throughput improvement.

Highlights

T HE DEPLOYMENT of the fifth generation (5G) cellular networks is accelerating across the world
The amplify-andforward aided space shift keying (SSK) and blind Reconfigurable intelligent surface (RIS)-SSK are excluded from the performance comparison, since they have been shown to be inferior to the intelligent RIS-SSK in [25]
In RIS-SSK-passive beamforming (PB), the RIS is employed for beamforming, which maximizes the minimum squared Euclidean distance between any two decision points

Summary

Introduction

T HE DEPLOYMENT of the fifth generation (5G) cellular networks is accelerating across the world. This wireless communication standard is expected to support lots of new applications and services, which require various enabling technologies. Energy-efficient transmission is a key enabler for energy-constrained networks, such as Internet of Things. The traditional digital modulation schemes that alter the amplitude, phase, and/or the frequency of a sinusoidal carrier signal often involve complicated operations, such as mixing and filtering.

Methods

Results

Conclusion