On the Achievable Max-Min User Rates in Multi-Carrier Centralized NOMA-VLC Networks

Maraqa, Omar; Siddiqi, Umair F.; Al-Ahmadi, Saad; Sait, Sadiq M.

doi:10.3390/s21113705

Cited by 3 publications

(6 citation statements)

References 53 publications

(93 reference statements)

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“…This work investigates two multiple access schemes, namely, power-domain NOMA and RSMA to boost the sum rate of the proposed system. While implementing these schemes, the number of intended users is assumed to be U and they have been sorted in order of their channel gain H 1 ≥ ... ≥ H u and H û ≥ ... ≥ H U [34].…”

Section: Adopted Multiple Access Schemesmentioning

confidence: 99%

“…The sum rate of the proposed system, for the power-domain NOMA and the RSMA schemes, are detailed in ( 18) and ( 27), respectively. The total consumed power of the proposed system encompasses various components: Firstly, the consumed power at the VLC AP can be expressed as [16] P VLC-AP = P T-Circuit +P Driver +P PA +P Filter +P DAC +P S , (34) where P T-Circuit denotes the power of the transmitter external circuit, P Driver denotes the power of the LED driver, P PA denotes the power of the power amplifier, P Filter denotes the power of the filter, P DAC denotes the power of the digitalto-analog converter (DAC), and P S denotes the power of the signal. Secondly, the power consumed at the OSTAR-RIS can be expressed as…”

Section: Sum Energy Efficiency Optimizationmentioning

confidence: 99%

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Optical STAR-RIS-Aided VLC Systems: RSMA Versus NOMA

Maraqa,

Aboagye,

Ngatched

2024

IEEE Open J. Commun. Soc.

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A critical concern within the realm of visible light communications (VLC) pertains to enhancing system data rate, particularly in scenarios where the direct line-of-sight (LoS) connection is obstructed by obstacles. The deployment of meta-surface-based simultaneous transmission and reflection reconfigurable intelligent surface (STAR-RIS) has emerged to combat challenging LoS blockage scenarios and to provide 360 • coverage in radio-frequency wireless systems. Recently, the concept of optical simultaneous transmission and reflection reconfigurable intelligent surface (OSTAR-RIS) has been promoted for VLC systems. This work is dedicated to studying the performance of OSTAR-RIS in detail and unveiling the VLC system performance gain under such technology. Specifically, we propose a novel multi-user indoor VLC system that is assisted by OSTAR-RIS. To improve the sum rate performance of the proposed system, both power-domain non-orthogonal multiple access (NOMA) and rate splitting multiple access (RSMA) are investigated in this work. To realize this, a sum rate maximization problem that jointly optimizes the roll and yaw angles of the reflector elements as well as the refractive index of the refractor elements in OSTAR-RIS is formulated, solved, and evaluated. The maximization problem takes into account practical considerations, such as the presence of non-users (i.e., blockers) and the orientation of the recipient's device. The sine-cosine meta-heuristic algorithm is employed to get the optimal solution of the formulated non-convex optimization problem. Moreover, the study delves into the sum energy efficiency optimization of the proposed system. Simulation results indicate that the proposed OSTAR-RIS RSMA-aided VLC system outperforms the OSTAR-RIS NOMA-based VLC system in terms of both the sum rate and the sum energy efficiency.INDEX TERMS Visible light communication (VLC), optical simultaneous transmission and reflection reconfigurable intelligent surface (OSTAR-RIS), reflecting intelligent surface (RIS), rate splitting multiple access (RSMA), non-orthogonal multiple access (NOMA). I. Introduction

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Section: Adopted Multiple Access Schemesmentioning

confidence: 99%

Section: Sum Energy Efficiency Optimizationmentioning

confidence: 99%

Optical STAR-RIS-Aided VLC Systems: RSMA Versus NOMA

Maraqa,

Aboagye,

Ngatched

2024

IEEE Open J. Commun. Soc.

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“…According to the NOMA scheme, each user needs to perform successive interference cancellation (SIC) to decode its information [39]. For simplicity, we assume that there is no residual interference after performing the SIC process (i.e., perfect SIC) [40]. Accordingly, the sum rate of the proposed system can be expressed as…”

Section: Multi-user Scenariomentioning

confidence: 99%

“…Both the dimension of the considered mirror array-based RIS (in the y-z plane) and the dimension of the wall of interest (in the x-z plane) is 1.0 m×3.0 m. The room size is 5.0 m×5.0 m×3.0 m and the VLC AP is positioned at the center of the room ceiling with a position vector 2.5 m×2.5 m×3.0 m. In the simulation of the NLoS scenario, we set I to zero. All the parameters used in this section are quoted from [2], [8], [38], [40], [42], [43].…”

Section: Parameter Valuementioning

confidence: 99%

Optimized Design of Joint Mirror Array and Liquid Crystal-Based RIS-Aided VLC Systems

Maraqa

Ngatched

2023

IEEE Photonics J.

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Most studies of reflecting intelligent surfaces (RISs)assisted visible light communication (VLC) systems have focused on the integration of RISs in the channel to combat the line-ofsight (LoS) blockage and to enhance the corresponding achievable data rate. Some recent efforts have investigated the integration of liquid crystal (LC)-RIS in the VLC receiver to also improve the corresponding achievable data rate. To jointly benefit from the previously mentioned appealing capabilities of the RIS technology in both the channel and the receiver, in this work, we propose a novel indoor VLC system that is jointly assisted by a mirror array-based RIS in the channel and an LC-based RIS aided-VLC receiver. To illustrate the performance of the proposed system, a rate maximization problem is formulated, solved, and evaluated. This maximization problem jointly optimizes the roll and yaw angles of the mirror array-based RIS as well as the refractive index of the LC-based RIS VLC receiver. Moreover, this maximization problem considers practical assumptions, such as the presence of non-users blockers in the LoS path between the transmitter-receiver pair and the user's random device orientation (i.e., the user's self-blockage). Due to the non-convexity of the formulated optimization problem, a low-complexity algorithm is utilized to get the global optimal solution. A multi-user scenario of the proposed scheme is also presented. Furthermore, the energy efficiency of the proposed system is also investigated. Simulation results are provided, confirming that the proposed system yields a noteworthy improvement in data rate and energy efficiency performances compared to several baseline schemes.Index Terms-Reflecting intelligent surface (RIS), visible light communication (VLC), liquid crystals (LCs), random receiver orientation, achievable rate, energy efficiency (EE), line of sight (LoS) blockage. I. INTRODUCTIONT HE exponential increase in connected devices and the ongoing development of wireless applications are driving the need to explore alternative wireless communications options to radio frequency (RF) communications. Visible light communications (VLC) has emerged as a bandwidth-abundant, cost-effective, and secure communications technology. Subsequently, VLC is seen as a promising candidate for complementing RF communications in future wireless networks [1].In ordinary VLC systems, the line-of-sight (LoS) availability between the transmitter and the receiver is essential for

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“…These materials are metallic nanospheres in a dielectric structure, thin metallic rods isotropically distributed in a dielectric medium, splitting metallic elements in a dielectric structure, negative index meta-materials, and hyperbolic metamaterials among others. Unlike its mirror-array counterpart, which does not operate 1 Optical wireless communications have gained significant interest in recent years due to (a) their ability to offer large bandwidth required for the next generation of wireless applications and beyond [101]- [103] and (b) their low cost and ease of implementation with cheap transceivers. in refractive mode (as it only reflects the incident light), the meta-surface-based RIS can yield all light phenomena related to the impact of photon on the unit surface, i.e., reflection, refraction, scattering, and absorption.…”

Section: Optical Rismentioning

confidence: 99%

Relay Selection for Improving Physical Layer Security in D2D Underlay Communications

2022

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This paper investigates the physical layer security of inband underlay Device-to-Device (D2D) communication, where the direct link between D2D users is not available. In this respect, optimal relay and suboptimal relay selections are utilized to secure the D2D transmission. The eavesdropper uses either maximal-ratio combining or selection combining to increase the wiretapped signals. The D2D secrecy performance analysis is performed regarding the secrecy outage probability (SOP) and the probability of non-zero secrecy capacity, and closed-form expressions are provided for both relay selection approaches and verified using Monte-Carlo simulation. From the numerical results, it is shown that increasing the number of D2D relays enhances the secrecy performance of D2D communications. Moreover, the exact asymptotic analysis of the SOP is provided. It turns out that the diversity order of both relay selection approaches is the same.INDEX TERMS Physical layer security, D2D communications, secrecy outage probability, optimal and suboptimal relay selection, maximal-ratio combining, and selection combining., 1

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On the Achievable Max-Min User Rates in Multi-Carrier Centralized NOMA-VLC Networks

Cited by 3 publications

References 53 publications

Optical STAR-RIS-Aided VLC Systems: RSMA Versus NOMA

Optical STAR-RIS-Aided VLC Systems: RSMA Versus NOMA

Optimized Design of Joint Mirror Array and Liquid Crystal-Based RIS-Aided VLC Systems

Relay Selection for Improving Physical Layer Security in D2D Underlay Communications

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