Performance of Hybrid Satellite-UAV NOMA Systems

Abstract

This paper investigates the performance of nonorthogonal multiple access (NOMA) based hybrid satelliteunmanned aerial vehicle (UAV) systems, where a low Earth orbit (LEO) satellite communicates with the ground users via a decode and forward (DF) UAV relay. We investigate a two NOMA users system, where a far user (FU) and a near user (NU) are served by the UAV which is located at a certain height above the origin of the coverage circle. The channel between satellite and UAV is assumed to follow a Shadowed-Rician fading and the channels between UAV and users are assumed to follow a Nakagami-m fading. New closedform expressions of the outage probabilities for the two users and the system are derived. Different from other work in literature, we take into consideration different parameters affecting the total link budget. Additionally, we propose an algorithm for minimizing the system outage probability. The mathematical analysis is verified by extensive representative Monte-Carlo (MC) simulations. Finally, simulations are provided to demonstrate the impact of important parameters on the considered system as well as the superiority of the NOMA scheme the over reference scheme.

Outage Analysis of Coordinated NOMA Transmission for LEO Satellite Constellations

“….0007, and c 1 = c 2 = c f = 0.063. For the numerical results, we use the settings in Table 1 [34], [35]. Figure 2 plots the OPs of the three users versus the transmit SNR (ρ) using both NOMA and OMA schemes, where γ 0 = 0.5, the power allocation factors for the users are a 1 = 0.3, a f = 0.7, b 2 = 0.4, and b f = 0.6.…”

“…is the distance from the beam center of the j th LEO to U i , and ϕ s denotes the angle between the user and the beam center with respect to satellite. The previously mentioned parameters have great impact on the channel gains of the satellite-users links and the effective signals-to-interference plus noise ratios (SINRs) [27], [28], which mandates taking them into consideration different from similar terrestrial coordinated multiple access (CoMP) transmissions. The results in [27] show that the pointing error and the distance from the center of the satellite beam have an impact on the downlink performance.…”

“…The previously mentioned parameters have great impact on the channel gains of the satellite-users links and the effective signals-to-interference plus noise ratios (SINRs) [27], [28], which mandates taking them into consideration different from similar terrestrial coordinated multiple access (CoMP) transmissions. The results in [27] show that the pointing error and the distance from the center of the satellite beam have an impact on the downlink performance. The authors in [28] have investigated the effects of pointing errors on the ergodic capacity of uplink satellite users.…”

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

“…In [22], the authors have adopted deep reinforcement learning-based resource optimization for effective capacity maximization in NOMA LEO satellite networks. Gamal et al [23] have derived a closed-form expression for outage probability in cooperative NOMA satellite networks. The work in [24] has proposed a joint resource optimization for minimizing the capacity demand gap in NOMA LEO satellite networks.…”

AsyncFLEO: Asynchronous Federated Learning for LEO Satellite Constellations with High-Altitude Platforms

“…Our analysis of SHL takes into account four factors: i) freespace path loss, ii) antenna gain of the transmitter and receiver, iii) antenna pointing error and shadowing, and iv) fading of the channel. Consequently, the total link budget of SHL between a satellite k and a HAP h, without small-scale fading, can be expressed as [22]…”