RIS-Assisted Covert Transmission in Satellite–Terrestrial Communication Systems

Song, Da; Yang, Ziyi; Pan, Gaofeng; Shuai, Wang; An, Jianping

doi:10.1109/jiot.2023.3242086

Cited by 11 publications

(4 citation statements)

References 35 publications

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“…Researchers have also investigated sum rate maximization problems in RIS-enabled NTNs [5]- [9]. In [5], Dond et al have maximized the weighted sum rate of RIS-enabled NTNs.…”

Section: Recent Advances In Ris-enabled Ntnsmentioning

confidence: 99%

“…They use alternating optimization for power allocation, phase shift design and beamforming based on successive convex approximation, Charnes-Cooper and semi-definite programming methods. Furthermore, Song et al [9] have maximized the minimum covert rate in RIS-enabled NTNs by optimization the transmit precoding and RIS phase shift design.…”

Section: Recent Advances In Ris-enabled Ntnsmentioning

confidence: 99%

“…in [1]- [4]. The achievable gains in terms of sum-rate maximization for RIS-integrated NTNs are available in [5]- [9]. Such systems also possess the inherent capacity to significantly enhance the security of wireless systems, and some preliminary results on the physical layer security for RIS-integrated NTNs are available in [10]- [12].…”

Section: Introductionmentioning

confidence: 99%

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Reconfigurable Intelligent Surfaces Enhanced NOMA D2D Communications Underlaying UAV Networks

Khan,

lagunas,

Mahmood

et al. 2023

Preprint

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<p>This paper considers RIS enhanced D2D communications underlaying unmanned aerial vehicle (UAV) networks with non-orthogonal multiple access (NOMA). The objective is to maximize the sum rate of NOMA D2D communications by optimizing the power budget of D2D transmitter, NOMA power allocation coefficients of D2D receivers and passive beamforming of RIS while guaranteeing the quality of services of UAV user. Due to non-convexity, the optimization problem is intractable and challenging to handle. Therefore, it is solved in two parts using alternating optimization. Simulation results unviel the performance of the proposed RIS enhanced D2D communications scheme. Results demonstrate that the proposed scheme achieves 15\% and 27\% higher sum rates compared to the fixed power D2D and orthogonal D2D schemes.</p>

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“…Researchers have also investigated sum rate maximization problems in RIS-enabled NTNs [5]- [9]. In [5], Dond et al have maximized the weighted sum rate of RIS-enabled NTNs.…”

Section: Recent Advances In Ris-enabled Ntnsmentioning

confidence: 99%

Section: Recent Advances In Ris-enabled Ntnsmentioning

confidence: 99%

See 1 more Smart Citation

Reconfigurable Intelligent Surfaces Enhanced NOMA D2D Communications Underlaying UAV Networks

Khan,

lagunas,

Mahmood

et al. 2023

Preprint

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“…When applied to LEO satellite networks, RIS can improve data transfer between satellites in orbit and mobile ground users. By strategically installing RIS, we can successfully reflect the incident signals in a desired direction, creating a highgain antenna [9]. System capacity, coverage, and energy usage can all improve as a result of improved signal strength and decreased interference.…”

Section: Introductionmentioning

confidence: 99%

When RIS Meets GEO Satellite Communications: A New Sustainable Optimization Framework in 6G

Khan

Lagunas

Mahmood

et al. 2022

2022 IEEE 95th Vehicular Technology Conference: (VTC2022-Spring)

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Low Earth Orbit (LEO) satellite networks are expected to play a crucial role in providing high-speed internet access and low-latency communication worldwide. However, some challenges can affect the performance of LEO satellite networks. For example, they can face energy and spectral efficiency challenges, such as high power consumption and spectral congestion, due to the increasing number of satellites. Furthermore, mobile ground users tend to operate with low directive antennas, which pose significant challenges in closing the LEO-toground communication link, especially when operating at a highfrequency range. To overcome these challenges, energy-efficient technologies like reconfigurable intelligent surfaces (RIS) and advanced spectrum management techniques like non-orthogonal multiple access (NOMA) can be employed. RIS can improve signal quality and reduce power consumption, while NOMA can enhance spectral efficiency by sharing the same resources among multiple users. This paper proposes an energy-efficient RIS-assisted downlink NOMA communication for LEO satellite networks. The proposed framework simultaneously optimizes the transmit power of ground terminals of the LEO satellite and the passive beamforming of RIS while ensuring the quality of services. Due to the nature of the considered system and optimization variables, the energy efficiency maximization problem is non-convex. In practice, obtaining the optimal solution for such problems is very challenging. Therefore, we adopt alternating optimization methods to handle the joint optimization in two steps. In step 1, for any given phase shift vector, we calculate satellite transmit power towards each ground terminal using the Lagrangian dual method. Then, in step 2, given the transmit power, we design passive beamforming for RIS by solving the semi-definite programming. We also compare our solution with a benchmark framework having a fixed phase shift design and a conventional NOMA framework without involving RIS. Numerical results show that the proposed optimization framework achieves 21.47% and 54.9% higher energy efficiency compared to the benchmark and conventional frameworks.

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