Hybrid RIS-Empowered Reflection and Decode-and-Forward Relaying for Coverage Extension

TL;DR

This paper proposes hybrid RIS and decode-and-forward relaying schemes that significantly improve wireless coverage and performance, offering a cost-effective and flexible solution for future networks.

Contribution

It introduces two novel hybrid transmission schemes combining RIS and relaying, with analytical expressions and optimization algorithms, demonstrating their complementary benefits.

Findings

Enhanced achievable rate and error performance with hybrid schemes

Closed-form expressions for end-to-end SNR

Optimization algorithms for power and phase configuration

Abstract

In this letter, we introduce two hybrid transmission schemes combining a passive reconfigurable intelligent surface (RIS) with decode-and-forward relaying in a synergistic manner. The proposed schemes offer a flexible as well as cost- and power-efficient solution for coverage extension in future generation wireless networks. We present closed-form expressions for the end-to-end signal-to-noise ratio of both schemes and a sequential optimization algorithm for the power allocation and the RIS phase configurations. Our computer simulations and theoretical analysis demonstrate that the RIS and relaying technologies enhance the achievable rate and error performance remarkably when working complementary to each other, rather than being considered as competing technologies.