Toward Ubiquitous and Flexible Coverage of UAV-IRS-Assisted NOMA Networks

Liu, Chun-Hung; Syed, Asif; Wei, Lu

doi:10.1109/wcnc51071.2022.9771729

Cited by 13 publications

(6 citation statements)

References 14 publications

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“…The LAPs follow an independent and 3D homogeneous PPP and a user device or subscriber (i.e., T-UE) is located at the center for each of the Monte Carlo trials. The probability of each of the LAPs being in LOS and NLOS with a T-UE is computed using (4) and (5), respectively. The received power of the MBSs, LOS LAPs, and NLOS LAPs is computed based on their distance from a T-UE and environmental path losses.…”

Section: Resultsmentioning

confidence: 99%

“…The research has examined connectivity and coverage performance, demonstrating enhanced network performance when UAVs are equipped with intelligent reflecting surfaces. Additionally, in a similar vein, the study conducted in [5] focused on modeling non-orthogonal multiple access within a UAV-assisted cellular network. The authors adopted a framework where base stations and UAVs follow 2D and 3D PPPs.…”

Section: Related Workmentioning

confidence: 99%

“…Therefore, to improve the reliability and ubiquitous coverage for the beyond-5G wireless networks, particularly in disaster-stricken scenarios such as earthquakes and tsunamis, where conventional infrastructure may be compromised, unmanned aerial vehicle (UAV)-assisted cellular communications is indispensable. Similarly, during temporary scenarios, such as establishing and managing remote COVID-19 quarantine stations, musical concerts, and sporting events, where traditional infrastructure is disrupted or not present and which demands increased capacity and ubiquitous coverage, the consideration of cellular networks assisted by UAVs or drones becomes pertinent [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Fluctuating Antenna Beamwidth in UAV-Assisted Cellular Networks

Arif,

Kim

2023

Mathematics

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This paper investigates a cellular network assisted by unmanned aerial vehicles (UAVs) in the presence of a fluctuating 3-dimensional (3D) antenna beamwidth. The primary objective is to perform an analysis of typical user equipment (T-UE) performance with a specific focus on coverage probability and spectral efficiency (SE) in the presence of fluctuations of 3D antenna beamwidth. Within this analytical framework, the macro base stations (MBSs) are meticulously characterized through the application of an independent 2D homogeneous Poisson point process (PPP), while the low-altitude platforms (LAPs) are described using an independent 3D PPP. The study entails the derivation of association probabilities, determining the likelihood of the T-UE associating with MBSs, line-of-sight LAPs, and non-line-of-sight LAPs. Through rigorous mathematical analysis, the paper formulates precise analytical expressions that encapsulate the association and coverage probabilities, taking into account the inherent variability in the UAV antenna beamwidth. This research focuses on a thorough performance evaluation of the T-UE across diverse network configurations, encompassing LAP density, the transmission power of LAPs, and the critical signal-to-interference ratio threshold. The outcomes of this study distinctly underscore the substantial disruptive impact resulting from fluctuating beamwidth on the performance of the T-UE within the UAV-assisted cellular network. Additionally, this performance is further impacted by larger densities and transmission power of the LAP. Hence, it is imperative to take into account the influence of these fluctuations on network association, coverage, and SE whenever contemplating a UAV-assisted cellular network.

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Section: Resultsmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of Fluctuating Antenna Beamwidth in UAV-Assisted Cellular Networks

Arif,

Kim

2023

Mathematics

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“…For example, Refs. [18,19] assume that IRS is mounted on a UAV. Reference [18] derives the outage probability for the proposed system and obtains the upper bound of the ergodic spectral efficiency.…”

Section: Introductionmentioning

confidence: 99%

“…Reference [18] derives the outage probability for the proposed system and obtains the upper bound of the ergodic spectral efficiency. In [19], Liu et al consider scenarios with multiple IRSes and UAVs. They derived and analyzed the maximum coverage probability achievable by two users.…”

Section: Introductionmentioning

confidence: 99%

Sum Rate Maximization for Intelligent Reflecting Surface-Assisted UAV-Enabled NOMA Network

Chen,

Liu,

Liu

2023

Electronics

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In the next-generation network, intelligent reflecting surface (IRS), non-orthogonal multiple access (NOMA), and simultaneous wireless information and power transfer (SWIPT) are promising wireless communication techniques to effectively improve system sum rates. In traditional unmanned aerial vehicles (UAV) communication systems, the sum rate and coverage are greatly affected when there is an occlusion on the direct transmission link. To solve this problem, the IRS technology is introduced to improve the poor channel conditions. However, most of the previous research on IRS-assisted UAV to optimize system sum rate only considers frameworks that utilize the partially joint-combining techniques of IRS, NOMA, and SWIPT. In this paper, in order to further improve the sum rate of the system, we simultaneously integrate IRS, NOMA, and SWIPT technologies and establish a sum rate maximization optimization problem when the direct link is blocked. Then, an alternative optimization (AO) algorithm based on the maximizing system sum rate is proposed to solve the non-convex optimization problem, in which the IRS location and phase, the reflecting amplitude coefficient, UAV forwarding altitude, and power splitting factor are considered. To let the non-convex and non-linear function be transformed into a convex one, we first use an iterative approach to optimize the position of the IRS. After that, an optimization problem is constructed to maximize the system sum rate with the constraints of the IRS phase shifts, successful successive interference cancellation (SIC), maximum transmit power of base station (BS), and UAV. Numerical results show that the proposed algorithm outperforms the traditional orthogonal multiple access (OMA) and algorithms without IRS-assisted links in terms of the system sum rate.

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