Non-orthogonal Multiple Access Enabled Two-layer GEO/LEO Satellite Network

Ge, Ruixing; Cheng, Jianwei; An, Kang; Zheng, Gan

doi:10.23919/eusipco54536.2021.9616017

Cited by 6 publications

(4 citation statements)

References 21 publications

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“…In a heterogeneous satellite network, users can connect to LEO satellites or be served by the GEO satellite. The authors in [20] focused on one user circumstance where the user can be served by the GEO and LEO satellites simultaneously. In detail, the ground user transmits a superposed signal to both satellites by applying NOMA, where the power allocated to the GEO signal is much higher.…”

Section: Literature Reviewmentioning

confidence: 99%

High Reliable Uplink Transmission Methods in GEO–LEO Heterogeneous Satellite Network

et al. 2023

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As a significant component of non-terrestrial networks, satellite communication has gradually evolved into a heterogeneous topology where the network nodes are classified as low Earth orbit (LEO) and geostationary Earth orbit (GEO) nodes. Considering the advantage of low transmission delay of LEO satellites in a heterogeneous network, ground users are arranged to access LEO satellites in the first priority. By fully understanding the equivalent channel gain difference in the beam-edge and beam-center users, we develop non-orthogonal multiple access (NOMA) in an LEO network where different users are allocated in the same resource block. As a complementary strategy, the beam-edge user has the ability to connect the GEO satellite if the LEO links are not available. That is, the two users are served cooperatively by LEO and GEO satellites in an orthogonal manner. In this paper, we provide deep insights for the uplink transmission performance of NOMA and cooperative orthogonal multiple access methods. As a general metric, the analytical expressions of outage probability are derived and the diversity orders are also provided. The simulation results show that NOMA is capable of providing remarkable performance in low signal-to-noise ratio regions and is more promising when the channels are assumed to be ordered.

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Section: Literature Reviewmentioning

confidence: 99%

High Reliable Uplink Transmission Methods in GEO–LEO Heterogeneous Satellite Network

et al. 2023

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“…The research work in [27] has provided a fair resource allocation framework in cooperative satellite networks to maximize the minimum capacity. The authors of [28] have derived a theoretical expression of ergodic capacity to improve the spectral efficiency of LEO satellite networks. In another paper, the same authors have maximized the sum capacity of NOMA LEO satellite networks by jointly optimizing the user pairing and power allocation [29].…”

Section: A Recent Literature On Leo Satellite Networkmentioning

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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“…By substituting (2), ( 4), ( 6), (8), and ( 9) into (34), after some mathematical operations, the approximate expression for the ergodic rate of D q for N > 1 can be formulated as…”

Section: Ergodic Sum Rate and Energy Efficiencymentioning

confidence: 99%

“…The NOMA-based hybrid satellite-terrestrial relay system was investigated, in which the outage probability, asymptotic outage probability, and achievable rate were derived in [7]. In order to analyze the multilayer heterogeneous satellite network, the authors in [8] proposed a NOMA-enabled two-layer geostationary earth orbit/low earth orbit (LEO) satellite network, where the ergodic capacity of the proposed system was investigated in the case of coexistence of frequencies. In [9], a dedicated half-duplex (HD) terrestrial decode-and-forward (DF) relay was used to assist a user with weak channel condition to complete communications with the satellite.…”

Section: Introductionmentioning

confidence: 99%

On the Performance of the Unified NOMA Framework for Satellite-Terrestrial Networks with Hardware Impairments

Zhao

Yue

Kang

et al. 2022

Wireless Communications and Mobile Computing

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A unified nonorthogonal multiple access (NOMA) framework for satellite-terrestrial network is investigated over Shadowed-Rician fading channels, which can be applied to both power domain NOMA (PD-NOMA) and code domain NOMA (CD-NOMA). Under the realistic assumption of hardware impairments (HIs) and imperfect successive interference cancellation (SIC), the achievable outage probability of the paired users is analyzed first, and the closed-form expressions of exact and asymptotic outage probability are derived. Next, the ergodic sum rate is investigated in different levels of HIs and residual interference. In addition, the energy efficiency in the delay-tolerant transmission mode is studied to characterize the performance of the satellite-terrestrial network. Finally, the Monte Carlo simulation results demonstrate the accuracy of theoretical derivation and showcase the effects of a wide range of satellite channel parameters and the realistic assumption on outage probability, ergodic rate, and energy efficiency.

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Non-orthogonal Multiple Access Enabled Two-layer GEO/LEO Satellite Network

Cited by 6 publications

References 21 publications

High Reliable Uplink Transmission Methods in GEO–LEO Heterogeneous Satellite Network

High Reliable Uplink Transmission Methods in GEO–LEO Heterogeneous Satellite Network

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

On the Performance of the Unified NOMA Framework for Satellite-Terrestrial Networks with Hardware Impairments

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