Rate-Splitting Multiple Access: Unifying NOMA and SDMA in MISO VLC Channels

Shimaa Naser,Mahmoud Al-Qutayri,Wael Jaafar,Sami Muhaidat,Lina Bariah,Paschalis C Sofotasios,Octavia A Dobre

doi:10.1109/ojvt.2020.3031656

Abstract

The increased proliferation of connected devices requires a development of innovative technologies for the next generation of wireless systems. One of the key challenges, however, is the spectrum scarcity, owing to the unprecedented broadband penetration rate in recent years. Based on this, visible light communication (VLC) has recently emerged as an effective potential solution for enabling high-speed short-range communications. Yet, despite their undoubted advantageous features, VLC systems suffer from several limitations which constraint their capabilities. As a result, several multiple access (MA) techniques, such as space-division multiple access (SDMA) and non-orthogonal multiple access (NOMA), have been considered in VLC networks as an effective approach, among others, to circumvent these limitations. However, despite their achievable multiplexing gain, their overall performance is still limited compared to the overall potential of this technology. Motivated by this, the presented article offers two contributions: firstly, we provide an overview of the key MA technologies used in VLC systems and then we introduce rate-splitting multiple access (RSMA), and discuss its capabilities and potentials in VLC systems. Secondly, through realistic system modeling and simulations of an RSMA-based two-user scenario, we illustrate the flexibility of RSMA as well as its superiority in terms of the achievable weighted sum rate over NOMA and SDMA in the context of VLC. Finally, we discuss technical challenges, open issues, and research directions, along with the offered results and insights that are expected to be useful towards the effective practical realization of RSMA in VLC configurations.

Highlights

The exponential growth of connected devices and emergence of the Internet-of-Everything (IoE), enabling ubiquitous connectivity among billions of people and machines, have been the major driving forces towards the evolution of wireless technologies
It is recalled that OFDM suffers from the high peak-to-average power ratio, which is difficult to overcome in visible light communication (VLC) systems due to the nonlinearity of light emitting diodes (LEDs) [21], [32]–[35]
PERFORMANCE EVALUATION This section presents different scenarios for the application of rate-splitting multiple access (RSMA) in VLC systems, where we investigate their performance in terms of WSR, and compare them with space-division multiple access (SDMA) and non-orthogonal multiple access (NOMA) schemes

Summary

INTRODUCTION

The exponential growth of connected devices and emergence of the Internet-of-Everything (IoE), enabling ubiquitous connectivity among billions of people and machines, have been the major driving forces towards the evolution of wireless technologies. Reliability, low latency, and increased data rates In this context, the notion of visible light communication (VLC) has emerged as a promising energy efficient and green wireless technology for massive connectivity of users with increased quality of service (QoS) requirements, such as high data rates. Rate-splitting multiple access (RSMA) has recently emerged as a potentially robust and generalized MA scheme for future wireless systems, which is able to accommodate different users in a heterogeneous environment. SDMA can be realized from RSMA by using only the private parts to encode users’ messages This operation of splitting the messages into common and private parts enables RSMA to provide robust services for different network loads and users deployments.

VLC COMPONENTS AND CHANNEL MODEL

BACKGROUND

RSMA FOR VLC

PERFORMANCE EVALUATION

Findings

VIII. CONCLUSION