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Summary: Broad‐band satellite communication is an indispensable method to provide seamless connectivity for people especially in remote areas. This paper analyzes the performance of the forward link of a multiuser satellite system operating in Ka band, where a gateway delivers signal to a satellite that forwards the amplified signal to multiple users on the ground. By assuming that satellite links experience double lognormal fading due to rain attenuation and taking the effects of antenna pattern and path loss into account, we first exploit the opportunistic user scheduling (OUS) scheme to obtain the maximal output signal‐to‐noise ratio (SNR) expression of the satellite system. Then, the analytical expressions for both outage probability (OP) and ergodic capacity (EC) of the considered satellite system are derived. Finally, simulation results demonstrate the validity of the theoretical analysis and the superiority of the OUS scheme in comparison with round‐robin scheme. [ABSTRACT FROM AUTHOR]

In this article, we investigate the performance of a multiuser integrated satellite-terrestrial relay network (ISTRN) with the threshold-based decode-and-forward protocol, where the satellite-relay link undergoes shadowed-Rician (SR) fading, while the relay-user links experience Nakagami-m fading. We first formulate a constrained optimization problem with an objective to maximize the system capacity in order to determine the beamforming weight vectors at the relay and thereby develop two multiuser scheduling schemes, namely, best user scheduling and user fairness scheduling. Then, we present a closed-form expression for the probability density function (PDF) of the square sum of independent and identically distributed SR random variables, which is more accurate and concise than the existing solutions. Based on the new PDF results, we derive closed-form expressions for the outage probability (OP) and ergodic capacity of the considered network using the two scheduling schemes. Furthermore, the asymptotic OP expressions at high signal-to-noise ratio are also deduced to reveal the asymptotic behavior of the considered ISTRN. Finally, simulation results are provided to validate our theoretical analysis and show the impact of various parameters on the system performance. [ABSTRACT FROM AUTHOR]

In this paper, we investigate energy efficient transmission for a satellite-aerial-terrestrial network (SATN), where a multi-antenna unmanned aerial vehicle (UAV) is employed as a relay to assist the satellite signal delivery. By considering total power constraint (TPC) or per-antenna power constraint (PPC) at the UAV, we first formulate an optimization problem to maximize the energy efficiency of the SATN, which is defined as ratio of the ergodic capacity to the total power consumption for communication at UAV. Then, by jointly exploiting array signal processing with the Dinkelbach’s method, two new beamforming (BF) schemes, namely, TPC-BF and PPC-BF are proposed to solve the non-convex energy efficiency maximization problem. The main advantage of our method is that only angular information-based channel state information is used to obtain BF weight vectors so that a low implementation complexity is achieved. Furthermore, by assuming that the satellite-UAV link undergoes correlated Shadowed-Rician fading while the UAV-terminal link experiences correlated Rician fading, closed-form expressions for the statistics of the equivalent output signal-to-noise ratio are derived and, thus energy efficiency for the considered SATN with BF schemes is analytically presented. Finally, simulation results corroborate the derived expressions and confirm the effectiveness of the proposed BF schemes. [ABSTRACT FROM AUTHOR]

Satellite and unmanned aerial vehicle (UAV) communications are the two most promising technologies for providing seamless connectivity to mobile users. In this paper, we investigate the performance of a multi-antenna multi-user integrated satellite and UAV cooperative network (ISUCN). Specifically, by taking many practical parameters, such as antenna pattern and path loss into account, we first obtain the maximal output signal-to-noise ratio (SNR) expression for the ISUCN, where multi-antenna UAV is employed as an aerial relay with threshold-based amplify-and-forward (AF) protocol to assist signal transmission between satellite and multiple ground users. Then, based on the commonly used assumption that the satellite link undergoes Shadowed-Rician fading while the terrestrial links experience Nakagami- m fading, we derive an analytical expression for the outage probability (OP) of the considered network. Furthermore, the asymptotical OP expression in high SNR regime is developed to evaluate the achievable coding gain and diversity order conveniently. Finally, numerical results are given to confirm the validity of the theoretical formulas and reveal the effects of representative parameters on the system performance. Our works provide useful guidelines for the engineers in the designing ISUCNs for futuristic satellite mobile communication systems. [ABSTRACT FROM AUTHOR]

In this study, we investigate the outage probability (OP) of a multiuser dual-hop satellite relaying system with decode-and-forward (DF) protocol, where both uplink and downlink experience Shadowed Rician (SR) fading. Specifically,by taking the effects of antenna pattern and path loss into account, we first establish a practical satellite channel model and obtain the end-to-end signal-to-noise ratio (SNR) expression for the considered system, where the uplink employs opportunistic scheduling (OS) scheme while the downlink adopts selection combining (SC) or maximal ratio combining (MRC) approaches. Then, we derive the closed-form OP expressions for the dual-hop satellite relaying with OS/SC and OS/MRC schemes, respectively. Furthermore, the asymptotic OP formulas at high SNR are also developed to gain further insights conveniently. Finally, numerical results confirm the validity of the theoretical formulas and reveal the representative parameters on the system performance. [ABSTRACT FROM AUTHOR]